Part 1 Plastics and the Marine Environment

In: The Mitigation of Marine Plastic Pollution in International Law
Author: Judith Schäli
Open Access

The massive accumulation of plastics in marine environments is internationally recognized as one of the most pressing environmental concerns of our time. This work examines the relevant international legal framework applying to land-based sources of plastic pollution, as well as its implementation at various levels of governance. Against the backdrop of the dynamics of recent policy formulation in this field, it outlines the main developments in global policy and provides a snapshot inventory of the most important obligations of states related to plastic pollution mitigation. Having laid the foundations for commitments to protect and preserve the marine environment and its biological diversity, the United Nations Convention on the Law of the Sea is at the core of the legal analysis. It plays an important role with regard to both coherence and international cooperation. The book evaluates the regime’s major traits and tests their practical impacts on the challenge of massive plastic accumulation in marine environments. It identifies the main barriers and opportunities, and points out the possible building blocks of an enhanced regime. Specifically, the book suggests the adoption of a global, legally binding instrument on marine plastic pollution mitigation from land-based sources.

Plastics are the materials that mark our age. To meet the legal challenges related to plastics, we need to apprehend their value and difficulties from a social, economic and environmental perspective. We need to take into consideration the impacts they have – on us and our environment in general, and on marine life and ecosystems in particular. This first part of the book is fully dedicated to plastic materials (1) and marine plastic litter (2).

1 About Plastic Materials

In Section A, I will shed light on different aspects of the nature of plastics. Section B takes a close look at the end-of-life stage of plastics and shows whether and to what degree plastics have the ability to biodegrade. The section also deals with waste, which corresponds to the most hazardous and costly life-cycle stage of plastics. Section C deals with life-cycle analysis and impact assessment. Overall, this chapter aims at providing the necessary background knowledge for the legal discussion.

A The Nature of Plastics

A basic understanding of the chemical make-up and properties of plastic materials seems to me essential for any discussion on their sustainable use. This includes an idea on challenges related to biopolymers (i) and plastic additives (ii), some of which are of a major concern in the (marine) environment. I will also discuss the economic background and spirit in which plastics have been developed, and explain the main industry sectors in which the materials are used (iii).

i Terms and Definitions

Plastics are made of large molecules, known as polymers. Polymers are chemical substances consisting of long chains or networks of smaller molecules.22 With the help of heat or specific chemical reactions, a high number of small molecules are linked together in repeat units, either in the form of long (straight or branched) chains or in the form of networks.23 It is through this process of polymerization that the individual constituent molecules, which are called monomers,24 join together to become very large molecules, or macromolecules, as the polymers may be called as well.25 Both the Greek prefix poly (many) and the Latin term macro (long, large), allude to the repeat units in the polymers, the resulting length of the molecular structure and their relatively high molecular weight.

Owing to their chemical structure, plastics exhibit special qualities and useful properties. These properties are reflected in their name: the word ‘plastic’ comes from the old Greek word plastikos, which referred to something capable of being moulded or shaped. With the emergence of synthetic materials in the early twentieth century, the plural form ‘plastics’ came into use, indicating a ‘commercial […] class of substances […] worked into shape for use by molding or pressing when in a plastic condition’.26 Today, when speaking of plastics, we generally refer to polymeric organic materials, most often synthetic, that can be processed by flow during their manufacturing, but become solid in their final stage. When referring to plastics in a narrow sense, materials such as fibres, adhesives and paints – and sometimes also rubbers – are often excluded, even if they mainly meet the definition.27 In a broader sense, however, these materials are also covered by the term.28 The term ‘resin’ is sometimes used as a synonym for plastics or plastic feedstocks.29

Plastics are organic substances, which means that carbon is a main constituent in their chemical structure. Because of its tendency to link up with other atoms and, more importantly, with itself,30 the carbon atom is predestined to form substances of extremely high molecular weight.31 This being the case, carbon is the basic constituent of living matter. Organic polymers are thus ubiquitous in nature. There are, however, some differences in the chemical structure of natural organic polymers and the average plastic material. These differences have a fundamental impact on the properties of respective materials, including with regard to their biodegradability.32

Natural organic polymers can be found in a vast number of materials, including plant and animal tissue. They are typically synthesized within cells by complex metabolic processes. Some of the most prominent natural polymers are proteins and cellulose, but also lignin, starch, chitin and natural rubber.33 In contrast, the basic building blocks of synthetic polymers are not, as such, taken from nature but are derived from petrochemicals or other substances and are then reacted into a new substance. Natural gas, crude oil and coal are the main raw materials which synthetic polymers are currently derived from.34 Through distillation, cracking or solvent extraction, intermediate products, such as ethylene, are derived from these raw materials.35 The intermediate products serve as basic ingredients for plastics. The polymerized petrochemicals, together with a broad range of additives, form the feedstock of plastic granules, resins and pellets, which in turn are converted into all different kinds of products.36

Natural polymers often are highly complex in their molecular architecture, usually involving oxygen and other elements. By contrast, synthetic polymers, for instance as used in commodity plastics, are typically simple and uniform. This can easily be illustrated by the example of polyethylene, one of the most common plastics. Polyethylene consists of chains of an indefinitely large number of carbon atoms, each linked to two hydrogen atoms (see Figure 1).37 Importantly, plastic materials consist of much larger (and often more densely packed) polymers than average natural organic materials.38

Figure 1
Figure 1
Structural formula of ethane, ethene and polyethylene

Plastic materials are often classified according to their thermal behaviour.39 Thermoplastics mainly consist of linear chains or of string-like molecules, sometimes with branches on one or the other side of the chain, or on both sides. They are either amorphous, which means that the molecules are not organized in a specific lattice pattern, or semi-crystalline, which means that the molecules are organized in such patterns in some areas but not in others. Some plastics have a fairly high degree of crystallinity, which means that their chain molecules are well ordered to a large extent. Above a certain temperature, the molecules have enough energy to overcome the intermolecular attractions and start to slide past each other. As a result, the material starts to flow.40 Thermoplastic materials, whether amorphous or crystalline, may therefore be deformed after heating, and remain in shape once they have cooled and become solid again. This process can be repeated for various times. Thermoplastics are the most important class of plastic materials that are commercially available today and include high- and low-density polyethylene (pe), polypropylene (pp), polystyrene (ps), polyvinylchloride (pvc) and many more.

By contrast, thermosets consist of three-dimensionally interlinked, close-meshed networks of molecules (see Figure 2). The chemical crosslinks within these networks inhibit the individual molecules from sliding apart and prevent the substance from melting or softening. Only with relatively high temperatures do the molecules chemically decompose.41 As a result, the material chars. In addition to their heat resistance, thermosets are often quite resistant to solvents such as gasoline, oils or cleaning fluids, and stand out due to their mechanical and physical strength. Thermosetting materials include epoxy resins, phenolic resins, amino resins and polyester resins.

Polymers with wide-meshed networks and chemical crosslinks are called elastomers (elastic polymers). The term rubber is sometimes used as a synonym of elastomer, but may also refer to a substance that is obtained by coagulating the milky juice of certain plants (the substance is also known as caoutchouc, India rubber or polyisoprene and is, unless processed into hard rubber, one of the most important representatives of the elastomers). At room temperature, elastomers are relatively elastic when compared to the close-meshed thermosets. They may be stretched to great extent, and regain their original shape once the stress is released. The degree of elasticity depends on the chemical structure of the chain sections, the number of bonds and crosslinks between the chains, as well as the density of the networks and the respective size of network meshes.42

Figure 2
Figure 2
Order and arrangement within different types of polymers
adapted by permission from springer nature customer service centre gmbh: hans domininghaus, die kunststoffe und ihre eigenschaften by peter elsner, peter eyerer and thomas hirth eds, © 2005 springer

Plastics can also be classified according to their performance. The cheapest and most widely used plastic materials are commonly referred to as commodity plastics. Everyday objects, including single-use items and plastic packaging, are usually made from this kind of materials.

The term engineering plastics refers to plastics ‘that have mechanical, chemical, electrical, and/or thermal properties suitable for industrial applications’. It has been defined as thermoplastic or thermosetting polymers ‘that maintain their dimensional stability and major mechanical properties in the temperature range 0–100°C’.43 Engineering plastics are more expensive than commodity plastics, and are thus produced in lower quantities and preferably used in very specific or high-quality applications.

At the very top of the performance (and price) scale are high-performance plastics, which have an extraordinary thermal and/or chemical stability and may also differ from other plastics in their mechanical properties.44 Their development, which mostly took place in the 1960s and 1970s, goes hand in hand with contemporary progress in new technologies, especially in the aerospace and nuclear industries, but also in medicine. Because of their premium price and complex processing requirements, there are comparably low quantities of these materials.

While in total there are thousands of different types of plastics, about 85 per cent of the world’s plastic materials belong to a group of five different kinds of plastics: pe, pp, pvc, ps and pet.45 These are the main commodity plastics of today. All of them are typically used in the form of thermoplastics. Ethene, propene, vinyl chloride and styrene are the respective monomers the former four plastics are produced with.46 As a common denominator, they are usually low-priced and used in huge quantities, including for disposable products and packaging. With very few exceptions, they are made from petrochemicals and do not or badly biodegrade.47

In order to facilitate recycling of these materials, the US Society of the Plastics Industry (spi), rebranded in 2016 as the Plastics Industry Association (plastics), introduced the Resin Identification Code (ric) system in 1988. The system assigns specific symbols (consisting of numbers from one to seven surrounded by an equilateral triangle) to the different resin types. The five above-mentioned plastic resins are assigned a number from one to six. All other types of resins fall under number seven. The system is broadly used across the world today (see Table 1).48

Both the fact that plastics are usually made from non-renewable resources and the fact that the majority of them do not biodegrade raised a call for more sustainable plastic materials. Since the early 1990s, these environmental challenges have been increasingly addressed by both scientists and manufacturers. On the one hand, they promoted plastics from renewable resources such as starch (so-called bio-based plastics).49 On the other hand, they developed plastics that are, in contrast to conventional synthetic polymers, biodegradable.50 The term biopolymers is sometimes used for both these groups of plastics and may, therefore, cause confusion. In fact, both polymers made from fossil fuel resources and from renewable resources may be biodegradable or not. With regard to the raw material they are produced from and their degradability, polymers can, as a consequence, be assigned to four different groups: non-biodegradable polymers made from non-renewable resources (generally referred to as conventional plastics), biodegradable polymers made from non-renewable resources, and both biodegradable and non-biodegradable polymers made from renewable resources.51

Table 1
Overview on main commodity plastics

P000465

Polyethylene

pe, with the recycling codes no. 2 for high-density polyethylene (hdpe) and 4 for low-density polyethylene (ldpe), is the most commonly used plastic of today. It has several benefits, including its extremely low price, excellent electrical insulation properties, chemical resistance, good processability, toughness, flexibility and transparency. Ethene, the main ‘raw material’ for pe production, was once obtained as by-product from the sugar industry but is now generally derived from ethane and propane, two petrochemical substances. Applications include sacks, carrier bags and other packaging materials, as well as films used in the building sector and for agricultural purposes, toys, containers, cases, buckets and many more items. pe is also often used in personal toiletries, including toothpastes and shower gels.

ldpe was discovered by two British chemists in 1933. It is obtained under high pressure and high temperatures. It has a relatively low density and a semi-crystalline, highly branched structure and softens at about 100–110°C. hdpe was developed at the beginning of the 1950s. It is harder than ldpe and has fewer branches, which allows the carbon chains to arrange themselves more closely in crystalline patterns. hdpe has a higher chemical and heat resistance. Further pe materials include linear low-density pe (lldpe) and very low-density pe (vldpe).

After the Second World War pe conquered private households, for istance through the famous Tupperware parties in the US, where housewives sold pe food containers among each other and generated their own income. In that, pe played its part in the emancipation of women from the 1950s.

P000470

P000471

Polypropylene

pp is made from propene, an alkene with the formula C3H6. It is identified with recycling code no. 5. Commercial exploitation of pp began in 1957. Today, the plastic is widely used in packaging, medical applications (including underbody applications) and automobile interiors, as well as in mouldings for boxes and cases, luggage and water bottles. pp is moreover used for bottle caps and drinking straws, and as fibres in carpets and other textiles. When exhibiting a high degree of crystallinity, pp is similar to hdpe in its properties, especially with regard to its chemical and electrical resistance, but has a higher melting temperature of at least 160°C. It is moreover stiffer and has high impact strength. Finally, pp is semitranslucent and, therefore, easily colourable. pp with a lower degree of crystallinity is often used in conjunction with bitumen as coating compounds in roofing materials and road construction.

P000474

Polyvinylchloride

pvc is made from the monomer vinyl chloride (C2H3Cl) and has recycling code no. 3. In 1931, the first commercially available vinyl long-playing record was launched by rca Victor. In the Second World War, plasticized pvc was used as a substitute for rubber in cable insulation and other applications. After the war, unplasticized pvc was increasingly used in the construction sector. The production of pvc was a welcomed opportunity to make use of the chlorine, an unpleasant by-product of the chemicals industries.

pvc is after pe and pp the third most widely used synthetic polymer. With the help of additives, the material’s properties can be tailored to an extremely broad range of applications, including pipes in drinking and waste water systems, insulation of electrical cables, vinyl floor coverings, window profiles, blood bags, toys and clothes.

The proportion of stabilizing agents, plasticizers and other additives may be substantial or even predominant in pvc applications. Some of these chemicals are carcinogens or interfere with the human hormone system (as so-called endocrine disruptors) when consumed. Since the vinyl chloride monomer was also found to have toxic effects,a regulations on its use (especially in food-contact materials) are common.b

Incineration of pvc is highly problematic, since it produces irritant, corrosive and toxic products, especially dioxins and furanes. Mechanical recycling of pvc as a hybrid of inorganic and organic substances and relatively high chlorine content also poses some challenges. In 2000, the European pvc industry established Vinyl2010, a ten-year commitment to improve the environmental performance of pvc. After expiration of the campaign, VinylPlus was launched in 2011 as a follow-up programme with the aim to tackle the sustainability challenges for pvc.

P000480

Polystyrene

ps is made from styrene (C8H8) and has recycling code no. 6. It is a low-cost, easily mouldable, generally transparent, rigid thermoplastic which is broadly in use today. It can be processed into nearly all different kinds of daily objects, including furniture, packaging and toys. It is also common in electronic applications. Since ps is hard and brittle in its pure stage, it is often copolymerized with other monomers. An important example in this regard is the copolymer acrylonitrile-butadiene-styrene (abs), discovered in 1948. Foamed ps, or expanded ps (eps), was developed in the 1950s and is often used as a foam in packaging materials and building insulation, as well as in disposable cups and plates. High-impact polystyrene (hips) is a more resistant and flexible material often used as a substitute for natural rubber.

P000483

Polyethylene terephthalate

pet, with resin identification code no. 1, is one of the most common members of the family of polyesters. Injection-moulded pet is transparent and amorphous. At room temperature, it is relatively rigid, strong and scratch-resistant, but sensitive to hot water and alkaline solutions. When heated above 80°C, it may shrink and change colour.

pet was first patented in the UK in 1941. Disposable pet beverage bottles were first marketed in 1977 and soon became one of the most important applications of pet. pet is also of great importance in the production of fibres and films. pet films are widely used in food packaging because of their tensile strength, chemical resistance, light weight and elasticity. pet played a pioneering role in the recycling industries.

Further developments

A broad range of engineering plastics has been developed along with the commodity plastics. Applications range from security glass, commonly known as Plexiglas, made from polymethyl methacrylate (pmma) to nylon stockings, polytetrafluoroethylene (ptfe) pot coatings, marine fisheries made from thermosetting polyurethanes (purs) and cds made from polycarbonate.

To this day, the sector is characterised by constant change and an ever faster pace of development. Many new plastics have been invented, and processing improved. Important developments have taken place in the fields of engineering plastics and high-performance plastics. Overall, today’s plastics are amazingly versatile.

In 1988, spi introduced triangular resin identification codes for different plastic materials, in order to facilitate recycling. In the 1980s and early 1990s, the first biodegradable plastics were developed. In 1990, the first light-emitting polymers were discovered at Cambridge University. New, biocompatible synthetic polymers are broadly used in medical applications, including in implantable drug delivery systems, tissue transplants or bone fixation devices.c Since the 2000s, synthetic nanomaterials have been on the advance and are increasingly used in commercial applications. More recently, the development of shape-memory-polymers (smp), that is, of polymers that are able to return from a deformed state to their original shape, has stimulated research for self-repairing and intelligent materials.d As for processing methods, 3D printing (also called additional manufacturing) is one of the sensations of today.e

a

See Hermann M Bolt, ‘Vinyl Chloride – a Classical Industrial Toxicant of New Interest’ (2005) 35 Critical Reviews in Toxicology 307, passim; Brydson (n 38) 312; Braun (n 22) 219.

b

See, for instance, Council Directive 78/142/eec of 30 January 1978 on the approximation of the laws of the Member States relating to materials and articles which contain vinyl chloride monomer and are intended to come into contact with foodstuffs [1978] oj L44/15.

c

Severian Dumitriu, ‘Preface’ in Severian Dumitriu (ed), Polymeric Biomaterials (2nd edn, crc Press 2001) v. See also S Sershen and J West, ‘Implantable, Polymeric Systems for Modulated Drug Delivery’ (2002) 54 Advanced Drug Delivery Reviews 1225, 1225; Jeffery A Williams and others, ‘Synthetic, Implantable Polymers for Local Delivery of IUdR to Experimental Human Malignant Glioma’ (1998) 42 International Journal of Radiation Oncology*Biology*Physics 631, 631.

d

Andreas Lendlein and Steffen Kelch, ‘Shape-Memory Polymers’ (2002) 41 Angewandte Chemie International Edition 2034.

e

See, for instance, Bettina Wendel and others, ‘Additive Processing of Polymers’ (2008) 293 Macromolecular Materials and Engineering 799.

ii Additives

Only very few synthetic polymers are suitable for commercial uses in solid products in their pure state. Most of them need the addition of adjuvants or auxiliary substances in order to meet the technological requirements in specific applications. With the same type of monomers (for instance vinyl chloride) but different modifiers or additives, a great variety of plastic products can be produced (e.g. rigid pipes, soft cable coats or foam plastic).52

Additives and other auxiliary ingredients may have the form of solids, rubbers, liquids or gases. They do not appreciably alter the chemical structure of the parent polymer. Yet, they alter the mechanical, electrical or chemical properties of the latter, and either facilitate processing or improve the final product’s qualities and appearance. They work, for instance, as fillers, plasticizers and softeners, uv or heat stabilizers, blowing agents, reinforcing agents, nucleating agents, cross-linking agents, lubricants, antistatics, antimicrobials, antioxidants, flame retardants, colourants or optical brighteners, impact modifiers, initiators or catalysts. In the form of heat and light stabilizers or antioxidants they delay chemical ageing. The substances may be added to the plastic feedstock at different production stages, both by plastic producers and converters.53

There is an extremely broad range of substances that are used as additives in plastics production. The list includes a high number of organic substances, such as phthalates,54 that are derived from petrochemicals and other materials by the chemical industry. Moreover, asbestos and other inorganic compounds can be found among the additives, including chlorine- and bromine-based flame retardants, barium, cadmium, lead or zinc compounds. The exact recipe for the production of a specific plastic is often a trade secret and remains unknown to the customers of the converting industry. While processing the materials into final products, converters may again add adjuvants to their feedstock.

Different sorts of additives as used in the industry have relevance beyond the mere processability of the resins they are used in or the performance and appearance of the final good, especially for their (alleged) environmental and human health impacts. Some additives are not or only weakly bonded to the polymer and may be released into the air or leach out of the plastic material into whatever material surrounds it, be it the ground or groundwater in landfills or the ocean.55 Migration of phthalates such as dehp from pvc blood bags into stored human blood and their accumulation in biological systems, including humans, was first discovered in the 1970s.56 Further studies revealed that no blood transfusions were necessary for phthalates to accumulate in human bodies; simple contact with everyday plastic goods would suffice for most people to have detectable amounts of phthalates in their bodies.57 Human exposure is, for instance, due to inhalation of contaminated house dust (or, more general, indoor air) and dermal absorption of lipophilic phthalates, as well as to the use of personal care products (skin and sun creams, shampoos etc.).58 Ingestion of contaminated food products is another route of exposure: when used in food packaging materials, additives can migrate into the food and be directly consumed by humans.59 Widespread contamination of bottled mineral water was demonstrated by a study in 2008.60

Phthalates and other chemicals used in the manufacturing of plastics, including bisphenol A (bpa),61 are released into the environment throughout their life cycle, including production, use and disposal.62 In the past few decades, they have become ubiquitous in the environment, where they persist.63 They are absorbed by animals and humans and can have a wide range of effects on their health, development and reproducibility. Minimal exposure level and doses required to cause harmful effects are highly controversial.

The Swiss physician and father of toxicology, Paracelsus (1493–1541), once found that the dose makes the poison. This means that, at a certain level of concentration, any substance has toxic effects, but at concentration levels sufficiently low, it remains harmless. Based on this presumption, modern toxicologists have generally assumed that, for any substance, there is a level of exposure for below which no effect can be observed. This level is generally referred to as no observed adverse effect level, or noael.64 In order to determine the noael of a chemical substance, a number of animal toxicity tests are usually carried out. In the tests, the substance is used on animals (such as rats or chimpanzees) in different, relatively high doses, until no adverse effects can be observed. To account for intra- and inter-species variations, a number of uncertainty factors are taken into account in the determination of acceptable human exposure levels, which are extrapolated from the noael.65 As long as environmental exposure (caused by the production, use or disposal of plastic goods) is far below the so defined threshold, no precautionary measures are usually postulated.

This way of proceeding is increasingly criticized by scientists, who have found evidence for a broad range of low-dose effects by different substances. Based on their observations, they have questioned the traditional (monotonic) dose–response concepts. In particular, substances that interact with the hormone system (endocrine system) of an organism (so-called endocrine disruptors66) supposedly have non-monotonic dose–response relationships, with maximum effects both at high and low doses,67 contrary to what Paracelsus’s statement suggests. Evidence indicates that they can be biologically active at concentrations far below the defined thresholds, including at doses within the range of current exposures in wildlife and humans.68

There is a broad range of studies on human and wildlife exposure to phthalates and bpa.69 Studies on health effects both in wildlife and humans are more complex and tend to be limited in scope.70 Adverse effects of endocrine-disrupting chemicals have been observed in birds, fish, shellfish and mammals, particularly humans.71 Phthalates were reported to have potential disturbing effects on the development and function of sexual organs, decrease reproduction levels and fertility, delay sexual maturity and cause morphologic abnormalities and malformations in the external genitalia, as well as increase the risk of endocrine-related cancer.72 Some data supports the hypothesis that exposure to endocrine disruptors at environmentally relevant concentrations can have transgenerational effects, which become apparent in the child- or adulthood of the next generation only.73 Foetal or childhood exposure may lead to altered sex differentiation, effects on neurological and reproductive development and increased risk of cancer.74 High concentrations of phthalates were also reported to increase asthma risk, rhinitis and eczema in children.75 Moreover, it has been discussed whether exposure to endocrine disruptors could be a possible cause for or contributing factor of widespread increase in obesity, as some animal experiments suggest,76 or neurodevelopmental disorders.77 Prenatal exposure to bpa was reported to cause changes in mammary and prostate gland development, with several effects on the children’s later development and health.78 Higher bpa concentrations in human blood were also associated with cardiovascular diagnoses and diabetes or recurrent miscarriages.79

Because of the observed effects, traditional dose–response concepts are claimed to be invalid for substances that imitate hormones or otherwise interact with the endocrine system. This might be explained by the very nature and functionality of the endocrine system, which is tuned to respond to very low doses of hormones.80 Also, conventional methods of determining acceptable exposure levels usually neglect possible impacts of the prolonged timing of exposure (given that human and wildlife exposure is constant or increasing throughout the years and effects on exposed individuals and populations may only become apparent in adulthood or offspring). Traditional methods furthermore neglect the fact that simultaneous exposure to a multitude of endocrine-disrupting agents might bear additional and widely unpredictable health risks, which are not taken into account in tests which involve single substances only.81

Regulations on the use and declaration of additives in plastic products vary widely around the world. Additives, including phthalates and bpa, do not always have to be declared in the final product. Measures such as bans and declaration requirements usually require a high degree of scientific certainty regarding the harmful effects of a substance on human health or the environment. For example, the European Union banned the use of six phthalate softeners in pvc children toys designed to be placed in the mouth by small children.82 Sensitive products also include food packaging materials, medical devices and baby bottles.

iii Economic and Social Considerations

The development of plastic materials is intertwined with the development of our economic models, lifestyles and social perceptions, and the history of war. Given the importance of plastics to our lives, it seems surprising that the first fully synthetic materials were developed just over a century ago. Their appearance at the beginning of the twentieth century heralded a new era of economic and social development. The development of plastics was boosted by new insights in polymer science, the shift from plant sources and coal to petroleum as a raw material in their production, the rapid growth of the petroleum industry83 and the development of new processing machines, such as the extruder and injection moulding machines.84 At the very basis of these developments, however, was the constant need for new materials with specific properties, such as insulating properties for cables. This need was driven by technological progress in the automotive, electronic, telephony, aircraft and cinematic industries and the two world wars. When plastic demand threatened to collapse after the wars, plastic manufacturers started to target the private sector. Advertising campaigns were launched to bring plastic products into private households. The product range was adjusted and now included products from all different sectors, including toys, cars, housing and clothing.

Important backing was provided by the governments: John M. Keynes (1883–1946) had revolutionized macroeconomic thinking by suggesting that economic growth depended highly on average demand. Many well-known economists followed the Keynesian line and advised governments to artificially stimulate private consumption. An often-cited article by Victor Lebow from 1955 brings the post-war economic dogma of the big economies and start of modern consumerism to the point:

Our enormously productive economy demands that we make consumption our way of life, that we convert the buying and use of goods into rituals, that we seek our spiritual satisfactions, our ego satisfactions, in consumption. The measure of social status, of social acceptance, of prestige, is now to be found in our consumptive patterns. The very meaning and significance of our lives today expressed in consumptive terms. The greater the pressures upon the individual to conform to safe and accepted social standards, the more does he tend to express his aspirations and his individuality in terms of what he wears, drives, eats – his home, his car, his pattern of food serving, his hobbies.

These commodities and services must be offered to the consumer with a special urgency. We require not only ‘forced draft’ consumption, but ‘expensive’ consumption as well. We need things consumed, burned up, worn out, replaced, and discarded at an ever increasing pace. We need to have people eat, drink, dress, ride, live, with ever more complicated and, therefore, constantly more expensive consumption.85

Plastics suited the purpose perfectly well. A broad range of items were designed, and consumers were tempted to buy them. Where a material once was designed to fill a need, its purpose was now to create one.86 The 1950s saw the rise of a range of plastic toys and other items, including the famous Barbie doll, which were distributed based on sophisticated marketing strategies. Plastics also rang in the ‘Machine Age’ in the average Western household: the age of radios, cars, electric washing machines and telephones.87 The wide proliferation of plastics started with consumer goods, intended to be durable, but more and more included disposable goods and packaging. In 1976, the American Chemical Council identified plastic as ‘the most used material in the world’.88 It has been so ever since. About 370 million tonnes of plastics were produced in 2019 – a tendency that is rapidly increasing.89

The global plastics industry had an estimated annual revenue of 1,722 billion Euro in 2015, which correspond to about 3 per cent of the total world economy in 2015. The majority of plastics are produced in China (28 per cent), North America (19 per cent) and Western Europe (19 per cent). The major plastics consuming regions are also China (20 per cent), North America (21 per cent) and Western Europe (18 per cent).90 According to recent estimates, exports of primary, intermediate and final forms of plastics amounted to more than US$1 trillion in 2018, or 5 per cent of the total value of global trade.91

Thanks to their exceptional versatility, both with regard to their physical and chemical properties and with regard to their appearance, plastic materials can be tailored to the specific needs of various industries. The biggest market for plastics is the packaging industry: about 40 per cent of all plastic materials are consumed by it.92 Packaging is one of the main sources of macroplastics found in the marine environment.93 According to recent estimates, one to five trillion plastic bags are consumed worldwide each year. This corresponds to almost ten million plastic bags a minute.94 Further markets include building and construction, and consumer goods (including home appliances and furniture, as well as sport, health and safety utensils). The automotive, electrical/electronic and agricultural sectors are also important customers of the plastics industry (see Figure 3).

Figure 3
Figure 3
European plastics demand by segment (2020)
‘plastics – the facts 2020: an analysis of european plastics production, demand and waste data’ © 2020 plasticseurope.

The reasons for the success of plastic materials in the packaging sector are manifold. Usually, plastic packaging is less expensive for the retailer to purchase than paper, metal or other alternatives. Second, it is light and takes less space than other materials (including on disposal). Third, plastic packaging often offers improved functionality to both retailers and consumers.95 Plastic packaging may, for instance, provide an extended shelf life to food, protect against infections and contribute to the reduction of food waste,96 all due to well-tailored barrier properties, moisture resistance and the possibility for a modified atmosphere within a food container. Meat is often packaged in plastic trays (made from expanded ps) and pvc films with high oxygen permeability. With the oxygen, the meat changes its purple colour into a bright red, which is generally preferred by consumers. The film thus not only protects the food from contamination and moisture loss but is also transparent and displays a product quality corresponding to consumer preferences. Plastic containers and bottles are relatively flexible and can be squeezed for the ease of dispensing. They don’t easily break when they fall down (e.g. shampoo bottle) and can be sterilized, which is important for medical instruments and devices.97

Due to all these benefits, and possibly also due to potential confusion with more traditional and more readily biodegradable packaging materials, plastic packaging is widely accepted as normal. It is perceived as an essential product component and used in quantities much beyond what is demanded by sanitary standards, including for products that have been provided by nature with highly convenient packaging (e.g. bananas).

B The End of Life of Plastic Materials

The end of life of plastic materials gradually gains public attention and media coverage, especially because of plastics’ high visibility within the waste stream. Also, there is growing awareness with regard to the biological inertness of most plastics and related potential ecological impacts. This section sheds light on the end-of-life stage of plastics. It explores their degradability (i) and discusses (plastic) waste management, as a lack of proper waste management is an important contributing factor to marine plastic pollution (ii).

i Degradation of Plastic Materials

Until recent years, degradability was generally seen as an undesirable characteristic of a material. In order to guarantee for durability and a long service lifespan of products, material degradation was to be avoided. This very aim has been a driving factor in the development of plastic materials. With the increasing use of throwaway products and the tremendous accumulation of plastic wastes both in waste treatment facilities and in nature, however, the positive effect of the longevity of plastics is queried. Instead, biodegradability is more and more perceived as a positive attribute of materials, especially when used in non-durable products with a supposedly limited service life.98

To date, the field of application of biodegradable plastics is still limited. Products have been launched in the fields of agricultural films, food packaging and shopping bags. Major obstacles for increasing their market share include their high production cost (which are especially due to small production volumes and expensive investments in research and development), the lack of policy incentives for environmentally sound materials and limited public awareness and acceptance.99 Label confusion is an aggravating factor in this regard: the biodegradability of plastics is not always easy to establish and much depends on specific environmental conditions. Sometimes plastics are labelled as biodegradable while they cannot biodegrade under prevailing disposal conditions. A consequence of such deceptive labelling may be that consumers directly dispose of their (supposedly biodegradable) products in the environment, where they fragmentize, disperse and persist. The use of biodegradable plastics has therefore been subject to widespread criticism.100 On the other hand, the future of real biodegradable plastics is regarded as promising, especially in medical applications and single-use products.101 The following subsections are dedicated to the degradation process of biodegradable and non-biodegradable plastic materials. Subsection 4) contains supplementary information on standards related to the degradability, biodegradability and compostability of plastic materials.

1) Degradation, Biodegradation and Composting

The degradability of an object depends on environmental conditions and other factors, including the form and composition of the degrading object. Degradation is induced by the presence of heat, sunlight, chemical substances (especially oxygen or water) and external stresses (abiotic degradation) or by the work of living organisms and enzymes (biotic degradation).102 Under atmospheric conditions, most of the degradation mechanisms involve chemical absorption of oxygen atoms in the polymer chain.103 Degradation affects the chemical bonds between the atoms of the polymer backbone. In doing so, it leads to an irreversible ‘change in the structure of a material, typically characterized by a loss of properties (e.g. integrity, molecular weight or structure, mechanical strength) and/or fragmentation’.104 It often also implies appearance changes, including loss of gloss, chalking, yellowing, or fading of colour. With progressing degradation, the material may get cracks on the surface and starts to get brittle.105 Visible signs of degradation are often referred to as weathering.106

Abiotic transformation processes of organic compounds often only lead to partial (or primary) degradation, fragmentation and cross-linking of polymers. For the fragments and residues to go through the final degradation phase and be mineralized, they need to be consumed by living organisms, most often microorganisms, as food and source of energy (secondary degradation). The breakdown of an organic chemical compound by microorganisms to carbon dioxide, water (or methane), mineral salts and new biomass is generally referred to as biodegradation.107 In the absence of suitable microorganisms, the fragments deteriorate into bio-stable microscopic parts susceptible to persist in the environment over an unpredictably long period of time.108 Biotic transformation processes are thus essential for ultimate degradation.109 This is especially true for aquatic systems, including the marine environment, where there is limited exposure to sunlight.110

Not every degradable material is considered biodegradable. Owing to solar radiation, heat, cold or other factors, a specific material may lose its properties or break down into smaller pieces up to a certain point. This does not, however, necessarily mean that the material can be decomposed by any kind of living organisms present in the respective environment and reconverted into metabolically useful chemical products in a useful period of time.111 Non-biodegradable materials thus fall out of the natural materials cycles. In the form of microscopic pieces or compounds, they persist in the environment and may cause harm to living organisms and ecosystems or pose a threat to human health.

The biodegradability of a material is not to be confused with compostability, which is defined much more narrowly. Compostability is the property of a material to biodegrade in a composting process. This implies that under the specific conditions of a composting system and within a given period of time (corresponding to a compost cycle), the material is biodegraded into an end product that meets the relevant compost quality criteria.112 These criteria include, for instance, the requirement that composted material does not leave any ecotoxic traces.113 Not every biodegradable material is compostable, and not every material that can be composted readily biodegrades in other environments.

Biodegradable plastics often are, but do not have to be, bio-based. Bio-based plastics are made from renewable materials.114 Possible raw materials for the production of bio-based plastics include corn or potato starch, tapioca, sugarcane, rice, wheat or cellulose, but can also be derived from vegetable oils, such as palm seed, linseed or soybean. Fermentation products, like polylactic acid, are also commonly used.115 Biodegradable plastics may be derived from petrochemical or renewable resources, and plastics that are made from renewable (bio-based) resources are not necessarily biodegradable.116 As a matter of fact, however, the two features (bio-based and biodegradable plastics) often come together, and are, as a consequence, easily confused.

2) Degradation Process of Plastic Materials
a) Conventional Petroleum-based Non-biodegradable Plastics

Many of the conventional plastics, including the big five (pe, pp, pvc, ps and pet), most commonly share the property that they do not biodegrade. Especially when they enter the marine environment as floating or submerged debris, they show extremely low rates of degradation.117 This is mainly due to the their morphology and high molecular weight:

  1. Morphology: In contrast to most natural polymers, conventional plastics often have regular configurations with short repeating units – a fact that allows the polymer chains to arrange in a very compact, crystalline order. High degrees of crystallinity make it difficult for living organisms to access the inside of polymer chains. Such polymers can hence only be attacked on their very surface, which is relatively small. By contrast, natural polymers, such as proteins, often have complex morphologies, which inhibit crystallization. The inaccessibility of crystalline parts for microorganisms and their extracellular catalytic agents is also the reason why in semi-crystalline polymers, amorphous parts are generally degraded first: the less-ordered packing of amorphous regions can be accessed more easily by enzymes than crystalline regions. The rate of degradation increases until the amorphous parts of a polymer are consumed. The cross-linked parts of a polymer are degraded at a slower rate.118
  2. Molecular weight: Proteins and other natural polymers can be converted into low-molecular-weight components by enzyme reactions which occur outside the microbial cell. By contrast, conventional synthetic plastics are not easily – or not at all – degraded by microorganisms in an extracellular environment. Apparently, there are no such mechanisms tailored by nature to most synthetic plastics.119 As a consequence, plastic objects are relatively immune to microbial attack as long as their molecular weight remains high. Only low-molecular-weight hydrocarbons can be degraded by microbes, as they can enter the cells and be converted into cellular metabolites inside the cells. In general, the more advanced degradation of a material is, the lower is the material’s relative molecular weight and the easier it gets for the microorganisms to access it.120

Conventional synthetic polymers such as pe, pp, ps and pet are considered highly bioinert and have to be degraded by abiotic mechanisms to the point that microbial attack can take place. However, even abiotic degradation of these polymers can be problematic. Most vinyl polymers are not susceptible to hydrolysis. High degrees of crystallinity and the use of antioxidants often also impede oxidation. In highly crystalline polymers, both H2O and O2 cannot diffuse easily.121 This being the case, degradation of these polymers is extremely slow, as the average length of, for instance, a low-density pe (ldpe) polymer chain exceeds the maximal length considered to be biodegradable by a factor of 400.122 Once the polymers have been broken down into low-molecular-weight components, microbes with the ability to decompose their specific chemical composition are needed to complete the degradation process. Yet, many microorganisms seem to lack the necessary genetic information for dealing with synthetic polymers and are unable to degrade them. Total assimilation of conventional polyolefins by microorganisms has not been proved yet.123

b) Petroleum-based Plastics with Enhanced Degradability

Non-biodegradable polymers are sometimes modified in such a way as to facilitate and accelerate degradation. Modifications include the addition of catalysts to promote oxidation or photo-oxidation, or the incorporation of easily oxidizable, hydrolysable or photosensitive functional groups into the polymer chain. Modified polymers are supposedly more susceptible to be attacked by heat, sunlight or other degradation mechanisms.124 While some evidences of degradation have been observed in modified pe, biodegradation of such materials is highly controversial. A counterproductive effect is assumed in that modification may result in more rapid fragmentation, increasing the rate of microplastic formation.125

c) Conventional Bio-based Non-biodegradable Plastics

Conventional commodity plastics such as pe and pet can also be produced from renewable resources. pe, for instance, can be made from agricultural products such as sugarcane or corn, as it was done in the early days of history of the material, before petroleum-based plastics gained traction. For the production of bio-based pe, ethanol is fermented from sugars as contained in agricultural products, and converted to ethene by the use of catalysts. Once polymerized, it has the same composition and properties (including biological inertness) as petroleum-based pe. Similarly, pp and pet can (partially) be produced from plant resources.126

d) Biodegradable Plastics from Petroleum-based or Renewable Resources

Polymers are considered biodegradable (or compostable) if they meet the respective standards as described in Subsection 4) below. Yet, as most of the standards refer to composting, plastics that meet the standards do not necessarily readily degrade in other environments, such as landfills or the marine environment.

Examples for bio-based biodegradable polymers include bagasse-based polymers,127 polyhydroxyalkanoates (phas), polylactic acid (pla) and starch-based polymers. phas are polyesters produced in the cells of bacteria by the fermentation of different substances, including lipids and sugar. The fermentation of sugars, most often from corn starches, also yields lactic acid, which can be polymerized to pla. Petroleum-based biodegradable polymers most often belong to the polyester family and include aliphatic polyesters such as polybutylene succinate (pbs) or polycarpolactone (pcl), as well as polyvinyl alcohol (pvoh/pva). Biodegradable plastics can be used for packaging, food containers, bottles, bags, agricultural pots and films or ground coverings.128

The first biodegradable plastics were developed in the 1980s. In the last couple of years, several biodegradable plastics have been introduced into the market. However, biodegradable plastics only hold a very small share of today’s plastic market.129 This might be due to elevated production prices and longer production processes for many of these plastics when compared to conventional plastics, as well as to a limited field of application. For many applications, the properties of most biodegradable plastics do not match the ones of conventional plastics.130 There is, however, an increasing interest in biodegradable materials, by both consumers and policymakers. Technological innovations and new developments can be expected in this field, which allow conventional plastics to be increasingly replaced by biodegradable ones.131

Biodegradable plastics are most usually non-recyclable. The need to separate biodegradable plastics from the non-biodegradable in the waste streams has been identified as a possible disadvantage of the widespread use of biodegradable plastics. Social misconceptions and a greater inclination to litter on the part of the public are further possible side effects that would seem most unwelcome.132

3) Degradation of Plastics in Marine Environments

Unlike plastics on land, floating debris cannot build up heat from the absorption of infrared radiation in sunlight, since ocean waters act as an efficient heat sink. Degradation of floating plastic debris is, thus, slower when compared to plastics exposed on land. This is even more true for submerged debris, since ultraviolet wavelengths in sunlight are readily absorbed by water. Moreover, marine debris is often susceptible to biofouling. The fouling coverage on the surface additionally shields the material from exposure to sunlight. While the degradation time for plastics in the marine environment is widely unknown, it is likely to be greatly increased at depth where oxygen concentrations are low and light is absent. Marine plastics thus degrade at a significantly slower rate than they do on land.133

4) Biodegradability Standards and Labels

There are considerable differences in the time materials take to break down or decompose under specific environmental conditions. In particular, the extent to which materials can be mineralized in a given period of time varies greatly. As a consequence, there is a need to agree on common standards that distinguish readily degradable materials from environmentally stable ones. Where the specific line is drawn is a question of threshold values.

Standards related to the biodegradability of plastics or their bio-based content have been developed by major standardization organizations, whether national, regional or international in character, and increasingly harmonized in recent years. Respective organizations include the International Organization for Standardization (iso), the American Society for Testing and Materials (astm), the Japanese Standards Association (jis) and the European Committee for Standardization (cen), an umbrella organization of the national standardization bodies of 34 European countries. Standardization bodies have adopted a large number of standards on plastics and could play an important role in a global approach to plastics. The iso technical committee 61 (iso/tc 61) works on plastics. Its subcommittee 14 was created in 2017 and works on environmental aspects in particluar. It has so far developed twenty-seven standards and has thirteen standards under development. The iso technical committee 122 (iso/tc 122) works on packaging, with its subcommittee 4 being dedicated to environmental aspects. iso/tc 323 was created in 2019 for standardization in the field of Circular Economy.134

Most standards as developed so far refer either to aerobic or anaerobic biodegradation or compostability performance of plastic materials under specific environmental conditions (and/or corresponding testing methods), or to the determination of bio-based content in plastic materials.

Biodegradation standards always refer to specific common disposal environments, including compost, marine, anaerobic digestion, soil and landfill.135 They determine to what extent a material has to undergo degradation in these environments within a given period of time in order to be qualified as biodegradable. In this sense, the qualification of an object as ‘biodegradable’ refers not necessarily to its property to completely biodegrade but to its ability to decompose to an environmentally acceptable level within a given time frame.136

Most performance specification standards refer to the compostability of products in industrial composting facilities. For plastic products, including packaging materials, to be labelled as compostable in such facilities, most standards require the product to demonstrate three characteristics:

  1. 1.Disintegration: When sieved in a 2-mm screen, no more than 10 per cent of the original dry weight of the plastic material must remain after 84 days/12 weeks/3 months of exposure to industrial composting conditions.
  2. 2.Biodegradation: At least 90 per cent of the organic carbon in the original plastic sample must be converted into co2 after a period of 180 days/6 months of exposure to industrial composting conditions.
  3. 3.No ecotoxicity: The resulting compost soil must support plant growth (no measurable phytotoxicity). Heavy metals concentrations in the compost soil must not exceed a certain level.137

Industrial composting conditions mostly include temperatures of at least 58°C and 50 per cent moisture. Cellulose, a material that is considered fully biodegradable, serves as a reference material.138 Some of the standards have been criticized for presupposing optimal composting conditions with regard to temperatures, water availability, aeration and duration, which are not easily met in real composting processes. It has been argued that as a result, even when a plastic product passes the tests, polymer biodegradation could be limited under real conditions and compost full of residues.139

Along with minimum biodegradation performance specifications, standards often specify testing methods for simulating the intended environment and measuring biodegradation of the samples.140 For some common disposal environments only test schemes are defined, while performance specifications are still missing.141

There are a few standards describing testing procedures to simulate the marine environment and methods to measure biodegradation. An astm performance specification standard referring to the biodegradation of plastic materials in marine environments was withdrawn in 2014.142 Requirements within the specification included criteria for the degree of plastic disintegration in marine environments, biodegradation rates and ecotoxicological testing. iso published two related standards in 2020, one defining the evaluation method for biodegradability in the ocean, the other specifying the method for evaluating the degree of disintegration in the ocean.143 Since these standards are not specifically aimed at assessing the biodegradability of plastics within anaerobic marine habitats, saltmarshes and deep-sea environments, it has been assumed that test methods and specifications can significantly underestimate the durations required for polymer biodegradation within natural marine ecosystems.144

Standards referring to the determination of bio-based content in a product usually provide test methods to measure such content and establish procedures, equipment, materials and conditions for the tests.145 A possible method to determine bio-based content consists of measuring the content of the 14C isotope in the plastic sample through radiocarbon analysis.146 Some standards require a minimum content of bio-based carbon in plastics as high as 99 per cent.147 The use of bio-based plastics may reduce the consumption of fossil-based resources and co2 footprint of a product.

Based on the standards, a number of certification programmes were developed. Products are tested by independent organizations and issued a certificate if they meet the requirements specified in a particular standard. The certificates often come with a label. According to the different sorts of standards, there are two major groups of labels. The first group proves that a product is biodegradable under specific conditions, for instance industrial or home composting or anaerobic digestion. The second group of labels indicates that the product contains a significant (minimum) percentage of renewable (bio-based) content. Labels can be awarded to finished products only (including packaging) and not to materials or ingredients as such. The validity period of certificates is limited, and testing is repeated in sporadic intervals.148

The Belgian certification agency Vinçotte International developed a conformity mark based on the withdrawn astm standard for products described as biodegradable in seawater (see Figure 4). Accepted products are required to exhibit a biodegradation rate of 90 per cent following six months of exposure.

Figure 4
Figure 4
Certification scheme for products described as biodegradable in seawater
Vinçotte, 2015, acquired by tüv Austria in 2017. Reprinted with permission by tüv Austria.

ii Plastic Wastes

When a plastic object comes to the end of its service life and is to be disposed, it enters –after production and use – the third major stage of its existence: the stage of waste. Waste is generally not regarded as a desirable stage of a product. The generation of waste implies a loss of materials and energy and entails environmental, social and economic costs. For this reason, there are efforts to minimize waste generation and keep the waste stage of a product as short as possible, by reintroducing the materials as used in the product into either the natural or socio-economic materials cycle. This not only allows resource and energy recovery and savings, but also leaves less waste to be stored and taken care of.

A sound waste management tries to keep waste, and plastic wastes in particular, out of wild nature and within a system managed and surveyed by humans. Waste management options within such a system include storage in a landfill (where degradability remains an issue), thermal treatment (including incineration) but also composting or anaerobic digestion, as well as different forms of recycling.149 Each of these disposal options handles the negative impacts of waste differently, and contributes to waste-reduction efforts in a more or less efficient way. Each of the options bears, however, its own environmental, social and economic costs. Trade-offs are, therefore, inherent to waste management policies, and require careful assessment and decisions.

The current subsection first briefly analyses how and in what quantities waste, and plastic waste in particular, is generated throughout the world (1). It then discusses some environmental, social and economic impacts of waste and waste disposal (2).

1) Waste Generation

Wastes can be defined as ‘substances or objects which are disposed of or are intended to be disposed of or are required to be disposed of by the provisions of national law’.150 It can be inferred from this definition that an object’s quality as waste alternatively depends on a factual element (effective disposal, including unintentional), a subjective element (the holder’s intention of disposal) or legal requirements, respectively. Plastic waste is potentially generated in the pre-production stage of a product (e.g. pellet loss), during production (e.g. plastic residues and other industrial wastes), during transportation (e.g. packaging, container spills) and after use (in the form of litter, dumped wastes or municipal solid waste). In this sense, wastes are by-products or end products of the production and consumption processes, respectively.151 In the case of by-products of the production process, we speak of industrial wastes. End products of consumption generally fall under the term of municipal wastes. The two categories can mingle and may have some overlaps (see Figure 5).

Figure 5
Figure 5
From resource extraction to waste disposal in a mainly linear system Source: Jagdeep Singh and others, ‘Progress and Challenges to the Global Waste Management System’ (2014) 32 Waste Management & Research 800, 801.
© 2014 sage Publications. Reprinted by Permission of sage Publications.

A distinction is generally made between solid wastes and non-solid wastes such as slurries, distillation residues, liquid pesticides, sewage sludges etc. In a plastic-specific context, the most relevant category of waste is that of municipal solid waste, which can be defined as solid waste collected and treated by or for municipalities. The term usually covers residential wastes in particular but often includes industrial, commercial and institutional (non-hazardous) solid wastes, as well as wastes from construction and demolition or municipal services. Medical and agricultural wastes might also be included, depending on whether they are managed by the municipality.152 Wastes that pose a risk to human health and the environment when composted, stored in a landfill or incinerated fall under the term of hazardous wastes and need to be recorded and disposed of separately. End-of-life vehicles, as well as electric and electronic wastes might also be collected and treated separately. Finally, agricultural wastes and wastes from mining and quarrying activities often belong to different, non-municipal waste streams.153

Solid waste has been regarded as the ‘most visible and pernicious by-product of a resource-intensive, consumer-based economic lifestyle’.154 Even 20 years ago, it was reported by the American National Academy of Sciences that ‘94 per cent of the substances that are pulled out of the earth enter the waste stream within months’.155 Production and consumption patterns are, therefore, highly relevant for any discussion on waste generation, being the main drivers in in this regard. Plastic materials cannot be exempted here, as they are widely associated with short-lived consumption and throwaway lifestyles.

a) Disposal Behaviour

The decision of a holder to dispose of a substance or an object may have different reasons. A plastic object may reach the end of its service life because it has fulfilled its purpose (e.g. packaging), because it breaks and repair is not considered a feasible option or worthwhile (e.g. tools and other basic commodities, sport equipment, kitchen utensils, tents, technical equipment and devices) or because it becomes otherwise useless, for example when its contents are consumed and the plastic container is not supposed to be refilled (e.g. packaging, disposable lighters, pens, tubes, ink cartridges etc.) or when it was designed for single use (e.g. disposable contact lenses, disposable nappies and other sanitary articles). Plastic objects are also frequently taken out of service and discarded because they no longer look new and lose their attractiveness (e.g. clothes, furniture, toys), do not meet new safety standards or sanitary regulations (e.g. in the case of new regulations with respect to food-contact materials or medical equipment), do not represent the state-of-the-art technology (e.g. cell phones and other electronic devices) or have become, for any reason, unfashionable (e.g. furniture, clothes, but also cars). As indivisible parts of bigger objects (e.g. houses and other constructions), their usefulness may come to an end whenever the latter are disposed of, demolished or discarded for any reason.

The lifespan of plastic products depends on many factors and differs significantly between different categories of products. Depending on whether they are designed as durable or disposable products, the average lifespan of plastic goods for usage varies from a few minutes (e.g. disposable dishes, straws, shopping bags) to several decades (e.g. aircraft windows, building floors or facades). In anti-consumerist circles, however, plastics, and commodity plastics in particular, are especially associated with disposables: as commodity plastics are cheap, many disposable objects are made from plastics (and vice versa: objects made from plastics are treated as disposables, since replacement is easily affordable). The list of such objects ranges from consumer goods that are relatively new to society (e.g. a broad range of toys, cosmetics, personal care items), to articles that were once designed as durables but are more and more perceived (and designed) as disposable objects, since they are easier to replace than to be stored and reused (e.g. packaging, containers, bags) or to be repaired when broken (e.g. home appliances). Boxes, dishes, bags and nappies were not usually disposed after a single use at times when they were made from more expensive materials such as wood, metal, ceramics or processed natural fibres. This is even more true for more complex goods, such as cameras or radios. While impetus for higher turnover rates and, with it, a higher throughput of resources in Western economies came from economic advisors and the media in the 1950s156 (that is, before the breakthrough of commodity plastics), and although early plastic products were designed to last long (e.g. Bakelite radios and telephones), plastic often serves, in public discourse, as a symbol for a wasteful society.

A critical issue of plastic disposables (especially when made from conventional plastics) is the obvious disproportion between the lifespan or service life of the product and the durability of the respective material used in the product. While the product is discarded rapidly, the raw material (that is, petroleum) has taken millions of years to be formed, and the product or its fragments will possibly persist in the environment for an indefinable period of time,157 in which it might have a series of harmful effects on humans, animals and entire ecosystems. The period of use is, thus, negligible in the product’s entire life cycle.

Durability of plastic materials has, hence, environmental, social and economic implications, and might be more or less reasonable, depending on the use and disposal of a product. While highly durable plastics pose a series of difficulties, readily degradable materials seem to be unsuitable for certain long-term applications, may not meet consumer expectations and are difficult to recycle (material recovery). The optimal lifespan of consumer goods was little discussed in the literature until recently.158 Today, however, the high ecological footprint of disposable products is well known.159

The phenomena of planned obsolescence and perceived obsolescence have received some more attention in literature, both academic and non-academic. In the first case, an object becomes obsolete because it was destined to break after a certain period of time or after it has been used for a certain number of times (e.g. light bulb, electronic devices). Software or hardware updates which are incompatible with previous versions and other programs or components, as well as a technical make-up which hinders repair or substitution of weak components, including batteries, often also fall under this term, as they push the consumer to upgrade across the board, including parts which are still working. In the second case, the holder of an object feels that it is outdated and should be renewed, for instance because it has become unfashionable or does not represent the state-of-the-art technology. Objects are then discarded and replaced by newer ones long before they are worn out. Both phenomena are said to be caused and controlled by the industry, either directly by the use of specific techniques to artificially limit the durability of a manufactured good or indirectly by influencing consumer perceptions through commercials and advertisement, suggesting that a model is outdated and should be replaced by a newer version.160

Literature critically reflecting on consumption (as a main driver for waste generation) and economic growth is broad and comes from several disciplines, such as psychology, sociology, ethology, economics and medical science. Topics include conspicuous consumption, a term that was first used by the economist and sociologist Thorstein Veblen in 1899 and refers to the widespread phenomenon of people purchasing goods, including luxury, for pure show-off and not to satisfy real needs.161Keeping up with the Joneses’ is a related phenomenon, which also includes the accumulation of material goods and status symbols in a constant status competition with the neighbours and struggle for social recognition which is based on material wealth.162 Several contributions focus on the question on how income and consumption levels influence our level of happiness. They describe and discuss human tendency to quickly return to a relatively stable level of happiness, even after positive stimulation through consumption.163 Hedonic adaptation, as the phenomenon is often referred to, is the reason for the fact that a rising level of consumption does usually not entail a general rise in subjective well-being, as one might expect. The constant (and mostly unsuccessful) attempt to push the level of happiness through consumption is associated with a treadmill: in order to satisfy raising aspirations with regard to their status, income level and consumption, people need to gain more and more and work harder, while subjective well-being rapidly falls back to its normal level. Pathological accumulation of obsolete items and the inability to discard them is known as a hoarding disorder.164 Differentiation between pathological hoarding and normal consumption behaviours is not always obvious. Furthermore, there is a range of literature examining new economic models, either suggesting a decoupling of economic growth and resource consumption or calling for economic degrowth.165 Finally, there are several contributions focusing on ‘sustainable’ or ‘green’ consumption, and the gap between green consumers’ values and their consumption behaviour, which often does not properly reflect the consumers’ ecologically oriented values.166

b) Sources, Quantities and Composition of Wastes

According to estimations of the World Bank, 2.01 billion tonnes of municipal solid waste were generated worldwide in 2016. This corresponds to 0.74 kg per capita per day, with considerable differences in waste generation rates between and within countries.167 In absolute terms, the East Asia and Pacific region is generating most of the world’s waste. North America produces the highest average amount of waste per capita, at 2.21 kg per day (see Table 2). Generation rates (per capita) of solid waste tend to be higher in high-income countries than in low-income countries, and in cities than in rural regions.168 The US is the largest generator of plastic packaging waste on a per capita basis, followed by Japan and the EU.169

Global annual waste generation is expected to grow to 3.40 billion tonnes by 2050. Daily per capita waste generation increases all over the world. It is projected to increase by 40 per cent or more in low- and middle-income countries by 2050, compared to a projected increase of 19 per cent in high-income countries. The fastest growing regions are Sub-Saharan Africa, South Asia, the Middle East and North Africa. In Sub-Saharan Africa, waste generation is expected to nearly triple by 2050. In these regions, more than half of the waste is currently openly dumped.

Table 2 and Figure 6 provide an overview of latest data collection and estimations by the World Bank, as published in 2018. They refer to municipal solid waste only.170

Table 2
Present and projected municipal waste generation according to region

Region

Total waste generation 2016 (mio tonnes/year)

Total projected waste generation 2015 (mio tonnes/year)

Waste generation per capita per day 2016 (kg/capita/day)

Waste generation per capita per day 2050 (kg/capita/day)

Middle East & North Africa

129

255

0.81

1.06

Sub-Saharan Africa

174

516

0.46

0.63

Latin America & the Caribbean

131

369

0.99

1.30

North America

289

396

2.21

2.50

South Asia

334

661

0.52

0.79

Europe & Central Asia

392

490

1.18

1.45

East Asia & Pacific

468

417

0.56

0.81

data source: slipa kaza and others, what a waste 2.0: a global snapshot of solid waste management to 2050 (world bank group 2018) doi:10.1596/978-1-4648-1329-0, p. 28. license: creative commons attribution cc by 3.0 igo.
Figure 6
Figure 6
Municipal waste generation by region
slipa kaza and others, what a waste 2.0: a global snapshot of solid waste management to 2050 (world bank group 2018) doi:10.1596/978-1-4648-1329-0, p. 19. license: creative commons attribution cc by 3.0 igo.

Important waste producing sectors include construction and demolition, mining and quarrying, the manufacturing industry, municipal solid wastes, waste and wastewater management, energy production and agriculture and forestry.171 Owing to incomplete and heterogeneous data, industrial waste generation rates are largely unknown. Available data suggests, however, that wastes from mining and production activities are considerably higher in mass when compared with wastes leaving the consumption system. This implies that for every kilo of household waste, up to seventeen kilos of industrial waste are generated in order to produce the discarded goods.172 Strictly speaking, the personal ‘waste footprint’ of individuals thus includes not only the waste discarded in person, but a multiple thereof, including industrial wastes generated along the production chain of the discarded goods.

Waste is extremely heterogeneous and its composition can greatly vary on a daily basis, between seasons and from one region to another. Geographical location, climate, culture and economic wealth are factors which greatly influence the composition of waste.173 Waste components can be categorized in different ways, for instance into (putrescible) organic, paper, plastic, glass, metal and other wastes. According to a recent study by the World Bank, consumption of plastics, paper and metals (including aluminium) increases with progressive urbanization and economic development. While all types of wastes tend to increase with higher (disposable) income, putrescible wastes (such as food and yard waste or wood) increase at a slower rate than plastic, paper and metal wastes. Accordingly, the share of plastics, paper and metals in municipal solid waste grows, while the fraction of putrescible organic wastes decreases.174

Globally, 12 per cent of all municipal solid waste is plastic waste, that is 242 million tonnes in 2016 (see Figure 7). Since plastic materials are, on average, considerably lighter than other materials, they represent much more than 12 per cent of the waste volume and, accordingly, occupy more space in landfills and as litter in the streets.175 The category usually includes bottles, packaging, containers, bags and small plastic items, but often excludes rubbers and synthetic textile fibres, which are counted separately, as well as plastics used in construction materials, paper coatings, electric and electronic wastes, bulky wastes and household goods.176

At least a third of global municipal waste is openly dumped. In low-income countries, 93 per cent of waste is dumped, compared to 2 per cent in high-income countries. Some 37 per cent of global waste is disposed of in some form of a landfill, 8 per cent of which is disposed of in sanitary landfills with landfill gas collection systems. Incineration is used primarily in high-capacity, high-income, and land-constrained countries. Globally, it accounts for 11 per cent of municipal solid wastes. Only 19 per cent is recovered through recycling and composting (see Figure 8).177

According to a study, approximately 6.3 billion tonnes of plastic wastes had been generated as of 2015, almost 80 per cent of which was accumulated in landfills or the natural environment. Three hundred million tonnes of plastic waste were generated alone in the year 2015. Without significant changes in production and waste management trends, about 12 billion tonnes of plastic wastes will be in landfills or the natural environment by the year 2050.178

Figure 7
Figure 7
Global solid waste composition
slipa kaza and others, what a waste 2.0: a global snapshot of solid waste management to 2050 (world bank group 2018) doi:10.1596/978-1-4648-1329-0, p. 29. license: creative commons attribution cc by 3.0 igo.
Figure 8
Figure 8
Global waste treatment and disposal
slipa kaza and others, what a waste 2.0: a global snapshot of solid waste management to 2050 (world bank group 2018) doi:10.1596/978-1-4648-1329-0, p. 29. license: creative commons attribution cc by 3.0 igo.
c) Recycling

Recycling is commonly seen as an important tool for waste minimisation. While degradable materials are returned to the agricultural value chain through the process of composting, recycling allows non-degradable materials to be returned to the industrial value chain. In a narrow sense, the term most usually refers to mechanical recycling, that is, material recovery in a proper sense.179 There are also other ways of reintroducing wastes into the value chain and consumption cycle, including through the reuse of an object per se, fuel recovery (chemical or feedstock recycling) or energy recovery (thermal recycling).180

Recycling is motivated by the revalorization of resources and the ‘sink value’ of the waste absorption capacity offered by recycling activities.181 Globally, less than 15 per cent of municipal solid waste is recycled (excluding energy recovery). In low-income countries, recycling rates tend to be high, while the biggest share of recycling activities can be attributed to the informal sector. Recycling markets are poorly regulated. By contrast, recycling in high-income countries is dominated by sophisticated collection services, high technology sorting and processing facilities, and effective regulation. Municipal recycling is promoted, with leading recycling cities achieving recycling rates of up to 70 per cent.182

Pre- and post-consumer thermoplastic polymers are sorted, washed, shredded and processed into ‘new’ polymers. The materials are upgraded, traded and fed into industrial supply chains. The purer the recyclate in resin types and colour, the more of the polymers’ original properties can be retained and the higher the quality of yielded goods. Usually, the recyclability of plastic materials is limited to about six return cycles. Recycling with inherent quality loss of the material is sometimes termed downcycling. Accordingly, upcycling refers to recycling processes in which value is added to the original product, for instance because of an improvement in economic and environmental performance, or because the new product is suitable for a broader range of applications.183

Durable goods are either collected by retailers, remanufacturers or kerbside collection services, or have to be dropped off.184 Many objects, such as vehicles, are not designed to be disassembled and recycled. Disassembly costs most usually are not contained in the product price. Both industrial and municipal solid wastes often also contain composite materials, the mechanical recycling of which is generally problematic.185 Adaptation of the product design to improve recyclability will take several years to show any impacts in recycling rates.186

The use of recycled plastics in food-contact materials is sometimes prohibited. Food containers made from recycled plastics therefore often include internal and external layers of virgin plastics in order to avoid contact between the recycled polymer and both the consumer and the food content.187

2) Costs and Impacts of Waste and Disposal

Integrated solid waste management addresses several issues: effective waste collection services help to maintain healthy conditions in cities, while careful waste treatment and safe disposal are necessary to reduce pollution and prevent waste-related environmental disasters.188 Moreover, sound waste management plays a central role in broader resource management, for it can allow the reintroduction of valuable secondary resources into the production cycle, while mitigating resource depletion. This being the case, solid waste management belongs to the key responsibilities of local governments and is often their single largest budget item.189 Full or nearly full cost recovery has so far only been achieved by high-income countries. While municipalities in high-income countries mainly invest in waste disposal, city governments in low-income countries spend most of their waste management budget on waste collection. Yet, collection rates in low-income countries tend to be lower, as collection is less efficient.190 About 3.5 billion people lack access even to the most elementary waste management services.191 As a result, uncontrolled waste disposal is still widespread.

Gradually, countries and cities move to more controlled forms of waste disposal. As a further step, they start now to move from mere end-of-pipe solutions to more sustainable and system-oriented forms of waste and resource management, which focus on waste prevention in the first place and allow for a circular economy, in which only small amounts of non-renewable resources have to be fed in and only small amounts of wastes are produced, as the bulk of the materials can be constantly renewed and reused.192

From the moment an object loses its usefulness and value to the holder, costs start to arise. The holder either has to store the undesirable object or organize its disposal. Costs of collection, transport, storage and final disposal of wastes, as well as of the respective infrastructure and its maintenance, either rest with the producer of waste, are formally borne by the municipalities and the state or – especially in the case of dumping – are otherwise passed on to the public at large or specific population segments in the form of negative externalities. Wastes have not only important economic implications but also various impacts on public health and the environment.

a) Social and Environmental Impacts

In the absence of appropriate collection and waste management services provided by or on behalf of municipalities, the informal sector often plays an important role in the collection of wastes, recycling and resource recovery. Dump sites in cities can be home to thousands of waste pickers who survive on the recovery of discarded materials.193 The scavengers, as the waste pickers are called, are heavily exposed to the risks associated with dumping sites, as they live under unhygienic conditions in a dangerous environment, while they often lack the minimum protective equipment.194

Waste disposal in open dumps or poorly operated landfills is generally associated with different forms of health and environmental risks, including the risk of direct physical harm by accidents, explosions and fires, as well as biological contamination of wastes with subsequent transmission of bacteriological pathogens through direct contact or food and water contamination. Dumps can be breeding grounds for disease-carrying rodents or insects. Chemical contamination of soil, food or water also counts among the risks and may have negative impacts on reproductive activities, notably stillbirth, low birth weights or specific birth defects.195 Rainwater absorbs soluble and suspended contaminants while it percolates the waste layers. Eventually, the contaminated water will leak out from the site and enter surface watercourses or groundwater aquifers, while polluting drink water supplies. Contaminants are ingested by fish and other animals, and bioaccumulate throughout the food chain.196 Health risks are moreover associated with the inhalation of noxious vapours that are emitted when dumped wastes decompose, or from toxic fumes that are caused by fires in the dump sites. Municipal wastes in open dump sites are often mixed with hazardous wastes, such as contaminated medical equipment, pesticides and other toxic chemical substances, batteries, mercury-containing wastes or explosives. Finally, open dumps often exacerbate the incidence of urban flooding and encourage poor sanitation habits.197 In cities and municipalities that rely on open dumping, it is mostly poor segments of the urban population that live close to dumping sites and are directly exposed to these risks and to contaminants in air, water and soil in particular. In these population segments, diarrhoea is twice as high and acute respiratory infections six times higher as in other segments benefitting from better waste management services.198 Children are especially vulnerable to the risks associated with wastes.199 Also, solid waste workers and informal waste pickers, who are frequently exposed to the dangers of waste, have higher risks of infections and parasites, diarrhoea and pulmonary problems, especially in developing countries.200

Open – or uncontrolled – burning of plastics and other types of wastes is strictly prohibited in many countries, but is common in regions with poor waste management services. It can produce large amounts of smoke, particulates and noxious odours. Persistent organic pollutants such as dioxins can be generated as by-products of incomplete incineration processes, especially when pvc or other chlorinated compounds are involved. Air pollution from open burning of wastes may cause severe health problems.201

Environmental impacts of landfills comprise ‘emissions of hazardous substances to soil and groundwater, emissions of methane into the atmosphere, dust, noise, explosion risks and deterioration of land’.202 Landfills and dumps are an important contributor to global methane generation and account for up to 20 per cent of anthropogenic methane production.203 According to the Intergovernmental Panel on Climate Change (ipcc), methane is a greenhouse gas with a global warming potential 34 times stronger than that of carbon dioxide if compared over a 100-year period.204 Since only a fraction of landfill facilities capture methane (and the ones that do, on average, recover only small percentages of total methane emissions), wastes in landfills significantly add to global warming.205 Biodegradable fractions of plastic wastes contribute to this effect.206 On the other hand, non-biodegradable plastics, which account for about 25 per cent of all solid wastes in landfills, are responsible for a decrease in landfill capacities, while they increase the risk of accidental fires with highly polluting emissions.207 Groundwater pollution by dump or landfill leachate also remains a widespread problem, even though it is technically feasible to collect the leachate, as is done in modern landfills.208 However, low- and middle-income countries often lack the necessary means for these technologies. Even in high-income countries, many landfills have been installed before high standards of groundwater protection were introduced. The remediation of old landfill sites is, therefore, an important task of waste management authorities.209 Because of leaking additives, plastics can be an important contributor to leachate toxicity.210

Solid waste disposal also plays an important role in terms of landuse: Wastes take up more and more land, especially within and close to cities. The availability of disposal sites within the collection areas becomes limited, and siting is often opposed by local residents.211 In small concentrations, wastes spoil landscapes and decrease their recreation value. In large concentrations, they pollute and severely deteriorate the land. The impact of plastic wastes in this regard is considerable. Because of their low density, plastics take more space when dumped and cause a greater visual impact on disposal than many other materials.212 In urban regions, poor segments of the population are often closer and more exposed to waste disposal sites. The placing of dumps or landfills therefore poses concerns of environmental justice.213

Incineration of wastes causes carbon dioxide and, thus, contributes to global warming. The burning of certain types of wastes, including pvc, also produces persistent organic pollutants,214 which are either released to the atmosphere or, when captured through efficient gas clean-up systems, contained in the solid residues and have to be landfilled. Air pollution and ash disposal are, thus, further challenges associated with waste incineration.215 Incinerators also require high investment and may be, for different reasons, an unsuitable disposal option for a specific municipality. If designed as waste-to-energy facilities, however, incinerators allow heat or energy recovery and electricity generation.216 In their solid form, plastic and other wastes may also serve as refuse-derived fuel in industrial processes. With this, fossil-fuel-derived energy can be partially substituted and reduced.

Negative effects of improperly managed composting facilities include potential pollution and health risks because of leachate and aerosols, odours, fires, dust and vermin.217 Gaseous emissions from composting often are malodorous and might be toxic. Bioaerosols can contain microbial organisms such as bacteria or fungi, the spores of which can lead to allergic responses.218 As a substitute for other disposal methods, however, composting of wastes can have a net positive environmental impact. Globally, about 46 per cent of municipal solid waste, especially food and garden wastes, is considered putrescible. Along with paper, card and certain types of (natural fibre) textiles, about three-quarters of global waste is potentially biodegradable. Separate collection of some fractions of this waste with subsequent composting removes large parts of biodegradable waste from the waste stream. Composting processes as a substitute for landfilling may reduce greenhouse gas emissions, ecotoxicity potential and eutrophication. The use of compost as a substitute for synthetic fertilizers entails additional positive effects, including with regard to water and electricity consumption.219

b) Economic Implications

From an economic point of view, wastes bear extremely high costs for individuals, private companies and municipalities. The collection and disposal of wastes often represents the largest budget item of cities and municipalities.220 Wastes, however, also bear secondary, less visible economic costs, including in the form of land degradation, lower agricultural yields or a decline in tourism. Waste-related clean-up costs and costs for soil and groundwater remediation can be important as well. Waste may also raise costs in health care and social protection. Furthermore, wastes impose opportunity costs in terms of land use and the allocation of financial resources. Finally, waste generation implies temporary or final loss of material or energy resources. The loss is temporary if efforts are made for resource and energy recovery, which again impose costs.

If recovery is possible, wastes provide an important potential source of valuable resources and energy. Waste management, including the recovery of resources, is an important economic sector. Also, the contribution of the informal waste sector to local economies often is substantial. Not only in low- and middle-income countries may the informal waste sector, including both individuals and micro-enterprises, compete with municipal collection and disposal systems.221 In China, about 20 per cent of discards are recovered for recycling, mostly by informal waste pickers.222 China also used to be the main importer of post-consumer waste plastics. In 2017, an estimated US$4.3 billion worth of plastic waste and scrap was exported worldwide, most of it by developed countries (71 per cent). The majority of importing countries are developing countries (75 per cent). China alone imported 64 per cent of plastic waste in 2017. China, however, banned the import of non-industrial plastic waste in 2018.223 China’s action triggered other countries in the East Asian and Pacific region to impose import restrictions on plastic wastes, including Indonesia, Malaysia, the Republic of Korea, Thailand, Viet Nam, and Taiwan Province of China. In 2019, global trade in plastic waste was 46 per cent lower than before the introduction of these import restrictions.224

C Life-cycle Analysis and Impact Assessments

Informed decisions play a decisive role in sustainable development. Without knowing the impacts of different options for action, diverse interests cannot be weighed against each other and balanced with the necessary diligence and care. It is not only the state, as the central regulatory authority and important procurer, but also private manufacturers and consumers that are important decision makers. They form our production and consumption patterns by their daily decisions, including with regard to material and product choices.

Environmental performance of plastic materials is currently gaining weight as a factor in the decision process, especially because of an increasing demand for environmentally sound materials.225 However, environmental and health impacts are often not easily measurable, quantifiable or foreseeable. Life-cycle assessments (lca) are a tool to evaluate potential impacts of different product alternatives, materials or disposal methods and compare them with one another. Given the many relevant factors and uncertainties in the life cycle of a product, lcas are highly complex, while their quality depends on the availability of extensive sets of useful data. They potentially measure the impacts of a product throughout its life cycle (from ‘cradle to grave’), ‘starting from the extraction of raw materials from the earth and ending at the waste products being returned to the earth’.226 lcas are commonly used in green or sustainable chemistry and engineering, a discipline tailored to advance sustainable development.227 They can play an important role in public and private environmental management, for instance in green procurement.228 Eco-labels and eco-design are also increasingly based on lcas. lca is only one out of several environmental management techniques and can be used along with other, complementary assessment tools.229

Although the approach was first used to assess life cycle-costs of investment goods, in particular in public procurement (e.g. weapon systems), the scope of lca traditionally focuses on environmental issues.230 The iso played a key role in the standardization of environmental lca (i). In more recent years, however, the assessment technique has been more and more applied in a broader context, and may include impacts beyond the environment. UN Environment increasingly promotes lca as a tool to better achieve sustainable development objectives and includes social and socio-economic impacts in what is called life-cycle sustainability assessment (lcsa) (ii). With regard to plastics, impact assessments generally serve to compare environmental footprints of different types of materials or different disposal options (iii).

i The iso Standard Series on lca

Building on the work of other international bodies, iso elaborated a series of standards to harmonize the application and interpretation of lca. The standard series increases comparability of different lca studies. In its main standard iso 14040:2006 (first published in 1997), the iso defines lca as ‘compilation and evaluation of the inputs, outputs and potential environmental impacts of a product system throughout its life cycle’.231 A product system in the sense of the iso standard is the total system of unit processes involved in the life cycle of a product.232 Input refers to the ‘product, material or energy flow that enters a unit process’, including ‘raw materials, intermediate products and co-products’.233 Energy and water consumption are covered by the standard. Land use is not directly referred to in the iso standard but is broadly accepted as an impact category.234 Output, on the other hand, refers to the ‘product, material or energy flow that leaves a unit process’, including ‘raw materials, intermediate products, co-products and releases’.235 Output as analysed in lcas generally includes waste generation and the emission of (hazardous) substances as caused by the extraction (or production) of input resources or by the production, transportation, use or disposal of the product.

The set of data on input and output of a product system is recorded in what is called a life-cycle inventory. Impact assessment methodologies help to translate this data into environmental impacts, for instance on human health, ecosystem quality or resource availability.236 lcas are, thus, mostly quantitative in nature. Where quantitative data is missing, qualitative aspects are taken into account.237 Once the impacts have been evaluated and quantified, different impact categories can be defined and compared, in order to identify unintended environmental trade-offs between such impact categories. Moreover, the environmental burden of different product alternatives can be directly compared.238

ii The Life Cycle Initiative

Even though the concept of lca was designed for assessing environmental impacts, the discussion on how to deal with social and socio-economic impacts within the lca framework is almost as old as the concept itself.239 In 2002, the Life Cycle Initiative was launched, a public–private, multi-stakeholder partnership which is hosted by UN Environment. The initiative is a response to the call for a life-cycle economy that was formulated by states around the world in the Malmö Ministerial Declaration in 2000.240 It moreover contributes to the 10-Year Framework of Programmes to promote sustainable consumption and production patterns,241 as requested at the World Summit on Sustainable Development in Johannesburg in 2002 and adopted at the UN Conference on Sustainable Development in Rio de Janeiro, Brazil, in 2012. With the initiative, UN Environment promotes life-cycle thinking, a concept to take into account environmental, social and economic impacts of a product over its entire life cycle in decision-making processes, as well as in the development of policies and products. The goals of life-cycle thinking are to reduce a product’s resource use and emissions to the environment and to improve its socio-economic performance throughout its life cycle. Within the concept of life cycle thinking, lca serves as a tool to find the potentials to reach these goals in each life-cycle stage, including production, packaging, distribution, use, maintenance, and eventually recycling, reuse, recovery or final disposal.

Under the auspices of the Life Cycle Initiative, lca methodologies as described in the iso standard are applied to aspects other than environmental ones. In 2009, UN Environment published guidelines for social lca of products that show how ‘production and consumption impacts on the workers, the local communities, the consumers, the society and all value chain actors’ can be included in the assessment.242

Similar assessment methodologies have also been applied to evaluate the overall costs of a product. Life-cycle costing takes into account all costs related to the production, use (or maintenance) and disposal of a product. In fact, the purchase price often reflects only a small part of the costs that are caused by a product throughout its life cycle.243 Costs that are not reflected in the product price and have to be borne by others are referred to as (negative) externalities. In life-cycle costing, these kinds of costs are anticipatorily included in the assessment if it can be assumed that they are to be internalized (due to new regulations) in the near future.244

When combining the traditional model of (environmental) lca with social lca and life-cycle costing, life-cycle thinking can be applied to the three pillars of sustainability (environmental, social and economic).245 Under the umbrella of the Life Cycle Initiative, this kind of holistic perspective is promoted as overarching lcsa. lcsa ‘offers a way of incorporating sustainability in decision-making processes’ and fosters the development of sustainable policies and products.246

iii lcas and Plastics

A number of studies have used lcas to examine and compare the environmental performance of different types of plastics and other materials, in order to provide guidance towards a more sustainable use, design and disposal of products. The majority of the studies compare conventional with biodegradable (bio-based) plastics, which have been synthesized in the quest for more sustainable materials. Some studies compare the environmental performance of plastics when used in specific applications to the environmental performance of other materials such as glass or paper. A small number of studies focus on recycling or compare different end-of-life options. Even when existing lcas consider waste management scenarios, they usually ignore environmental leakage of packaging. lca can be used not only to quantify product footprints, but also to evaluate the plastic footprint of individuals, companies, sectors or countries.247

The studies usually include different impact categories, particularly fossil resource depletion, carbon footprint and global warming potential. Further impact categories include smog creation, eutrophication, acidification, and human and ecosystem toxicity.248 The results of the assessments, and their comparability, heavily depend on the chosen system boundaries (cradle to granule, cradle to gate, cradle to grave or cradle to cradle), the materials (pla, starch-based polymers etc.) and kind of objects (packaging, disposable or durable objects) that are assessed, the impact categories that are observed, variable geographical or other conditions and basic assumptions made for the assessment, including with regard to allocation methods, the use fertilizers in (bio-based) feedstock production, the use of (non-) renewable energy in the whole production process and disposal options in cradle-to-grave analyses.249 Owing to these variables, results diverge from one study to another, while overall comparability is limited and may require normalization of the results and sensitivity or scenario analysis. The studies, however, provide an overview of the environmental and human health impacts of plastics within the system boundaries of the studies and show what trade-offs there can be between plastics and other materials, between biodegradable, bio-based and conventional polymer production or between different disposal options.250

With regard to the system boundaries, many studies are confined to cradle-to-granule or cradle-to-gate analyses, excluding the use and end-of-life phases of the products (see Figure 9). Even cradle-to-grave studies sometimes omit the use or transportation phases.251 Including the end-of-life phase in the assessment provides more comprehensive results, but also introduces greater amounts of uncertainty and variability, as there is, for instance, little life-cycle data available on the specific impacts of different disposal options.252

Figure 9
Figure 9
System boundaries of life-cycle assessments
adapted from troy a hottle, melissa m bilec and amy e landis, ‘sustainability assessments of bio-based polymers’ (2013) 98 polymer degradation and stability 1898 doi:10.1016/j.polymdegradstab.2013.06.016, p. 1900. © 2013 with permission from elsevier.

Throughout their life cycle, the different types of plastics have different impacts on human health and the environment:

  1. Fossil feedstock of petrochemical, non-biodegradable polymers can be calculated in energy rather than a material input by multiplying the amount consumed by its heat of combustion.253 To calculate total fossil fuel depletion of the product from cradle to gate, the energy necessary for processing the feedstock has to be added, as well as the energy for transportation. Cradle-to-grave analyses have to be based on assumptions on disposal methods. When the products are landfilled, the carbon in the plastic is not likely to contribute to global warming, since it is locked in the landfills for an indefinite period of time. In this scenario, the discarded products take a relatively large amount of space for the same period of time. When the products are incinerated, their carbon content, which before has been fixed within the fossil resource for several millennia, is set free and emitted to the atmosphere.254 When incinerated in waste-to-energy facilities, energy recoveries can be deducted from the total amount of used energy and fossil fuel depletion if they are used to substitute for fossil-based energy sources.255 Recycled plastics may have a smaller effect on global warming if less energy is used to recycle them than is needed for the production of virgin materials.256
  2. Bio-based polymers which are derived from agricultural products require prior cultivation of the crop that provides the feedstock. lcas on respective polymers thus include the fuel required for farming activities, as well as for the manufacture and transport of fertilizers, herbicides and pesticides. They might also include other impact categories such as land use, water consumption or soil depletion.257 Since their feedstock contains atmospheric co2, bio-based plastics that are landfilled at the end of their service life potentially reduce greenhouse gases in the atmosphere by sequestering carbon.258 This effect is, however, extenuated by the carbon released to the environment due to the production and use of these plastics, as well as through the collection, transport and processing of the garbage. Also, in some environmental impact categories, such as eutrophication, ozone depletion and non-carcinogenic human health, bio-based polymers might have higher impacts when compared to petroleum-based plastics.259
  3. Biodegradable polymers can be incorporated into organic recycling schemes based on anaerobic digestion or composting. As a consequence, less waste has to be sent for incineration or landfill, which reduces the impacts that are associated with these disposal methods.260 In composting processes, the carbon content of the materials is converted into co2 rather than methane, as would be the case in landfilling.261 Composting and anaerobic digestion can, however, also have negative impacts on the environment.262 Also, the actual disposal route of plastic products is mostly uncertain. Even if a product is compostable in industrial facilities, relevant infrastructure in a specific region is not necessarily sufficiently developed. Biodegradable plastics therefore often follow the main waste stream and predominant disposal methods. Landfilling of biodegradable plastics can negatively influence their environmental profile if they have the potential for methane emissions.263 Owing to a lack of data on the extent of biodegradation of different biopolymers in the different environments, on the main disposal routes of biopolymers and on the impacts of these disposal methods, ‘the environmental impacts associated with the creation, use, and disposal of [biodegradable] polymers remains unclear’.264
  4. Biodegradable plastics made from petrochemical feedstocks probably have the greatest potential to contribute to greenhouse gas emissions.265 When they degrade, they release fossil carbon dioxide to the atmosphere. If they biodegrade in a landfill, they might generate methane. Also, the environmental performance of hybrid plastics that are made from both bio-based and petrochemical feedstocks is relatively poor from a greenhouse gas emissions perspective. These materials usually are neither recyclable nor truly biodegradable.266

Figure 10 shows cradle-to-gate impact assessment results in ten different impact categories for a number of petrochemical and bio-based polymers, as well as a hybrid material. Results from the respective study show a disparity between bio-based and petroleum-based polymers: although bio-based polymers rank highly in terms of green design,267 they exhibit relatively large environmental impacts from production and, therefore, rank in the middle in lca rankings. Polyolefins perform well in cradle-to-gate lca analyses, whereas complex polymers (pet, pvc, and polycarbonate (pc)) place at the bottom of both lca and green design ranking.268

Most of the studies that have been reviewed for this chapter conclude that bio-based and/or biodegradable polymers that are currently available on the market are not necessarily more environmentally friendly than the petrochemical polymers.269 However, it is repeatedly emphasized that the environmental profile of this relatively young class of polymers is supposed to rapidly improve in the future.

Figure 10
Figure 10
Cradle-to-gate lca results for petroleum-based, bio-based and mixed polymers
reprinted with permission from michaelangelo d tabone and others, ‘sustainability metrics: life cycle assessment and green design in polymers’ (2010) 44 environmental science & technology 8264, 8266. © 2010 american chemical society.

lcas have also been used to assess the environmental performance and impact of recycled plastics. As the raw material extracting and manufacturing processes have the biggest share of the carbon footprint of a plastic product, recycling can considerably reduce the carbon footprint. The best results can be achieved if the proportion of recycled raw material is maximized and processing optimized.270 On the other hand, recycling often implies higher water usage due to the large amounts of water used in the washing process of recycled plastics.271 In spite of this, recycling offers substantial environmental advantages for petroleum-based plastics when compared to other disposal options, also due to a reduction of feedstock requirements and energy input.272

The recycling of biodegradable polymers is more complex. Traditional recycling facilities might not be properly equipped for dealing with these materials and cannot prevent them from fouling other recycling streams. Although it is technically feasible to mechanically recycle some biodegradable polymers, it currently is not economically attractive owing to the lack of continuous and reliable supply of corresponding waste materials.273

lcas can also be useful to compare the environmental performance of plastics and of other materials in specific applications. The results of such studies are ambiguous and strongly depend on the system boundaries of the studies and the chosen parameters.274 Plastic leakage to the environment and related impacts are often not included among the parameters examined.275 There are also information gaps relating to long-term impacts on ecosystems and health by microplastics. Furthermore, a lca-based report by UN Environment has clearly shown that the design and type of use of a product may have a greater influence on its environmental impact than the material itself. Reusable products usually have lower environmental impacts than single-use products. Replacing one disposable product (e.g. made of plastic) with another disposable product made of a different material (e.g. paper, biodegradable plastic) is only likely to transfer the burdens and create other problems. UN Environment therefore encourages states to replace single-use plastic products with reusable products as part of a circular economy approach.276

While they allow us to compare potential impacts of different materials or products, lcas circumvent the question whether a specific product is needed at all. However, the key to effective marine plastic pollution mitigation strategies may not only include careful, sustainable product design and recycling management, but also moderate, needs-based, environmentally sound consumer behaviour.

2 Plastic Pollution in the Seas

All through the history of human civilization, waste has been dumped in and close to the oceans or in rivers, lakes and other waterways. As long as populations were small and refuses mostly biodegradable, there was only little evidence of resulting human impacts on marine environments.277 Even today, there is a widespread belief that the ocean is resilient to human influences, no matter ‘how much we take out of – or put into – it’.278 Yet, with the industrial age, the tide has turned. Related phenomena such as rapid population growth, global warming and the widespread use and disposal of bio-stable materials that find their way into the oceans have brought about some fundamental changes. Our impact on the oceans has been detrimental in the last century and probably is, at least to some extent, irreversible.279 Human activities on land and the seas put increasing stresses and strains on the oceans and marine biodiversity to the extent that the capacity of the marine environment to regenerate may have passed its limit.280 Ocean pollution through marine littering, and plastics in particular, is only one out of a wide range of factors that drastically disturb the natural balance of the ocean.281 However, the issue presents us with enormous challenges, and is likely to do even more so in the future, as the full scale of the problem is still unknown.282

Marine pollution is generally defined as the ‘direct or indirect introduction by humans of substances or energy into the marine environment (including estuaries), resulting in harm to living resources, hazards to human health, hindrances to marine activities including fishing, impairment of the quality of sea water and reduction of amenities’.283 Marine litter, as one form of marine pollution, can be defined as ‘any persistent, manufactured or processed solid material discarded, disposed of or abandoned in the marine and coastal environment’.284 It consists of:

items that have been made or used by people and deliberately discarded into the sea or rivers or on beaches; brought indirectly to the sea with rivers, sewage, storm water or winds; accidentally lost, including material lost at sea in bad weather (fishing gear, cargo); or deliberately left by people on beaches and shores.285

Such items not only include plastic products or fragments but also glass, metals, natural fibres, paper and wood. Plastics, however, represent the biggest proportion of marine debris, and entail a number of particular challenges, especially their ‘nearly indestructible morphology’ and toxic substances they accumulate and/or release.286 Although plastics constitute only about 12 per cent of global municipal wastes, they comprise 60–80 per cent of wastes that are accumulated in marine environments, including beaches and coastal waters, ocean water columns and the seabed.287 Marine plastic pollution thus primarily involves the accumulation of plastic debris of all sizes in marine environments. The presence of widespread plastic debris – or litter – and microplastics in the sea poses a severe problem with a wide range of significant implications for the marine environment and its inhabitants, but also for human activities and health.

While representing one of the youngest generations of anthropogenic litter, which originated in the mid-twentieth century only, plastics are now ubiquitous in the marine environment.288 Although the problem of marine plastic pollution is commonly recognized, continuously rising production levels of plastics and quantities of existing marine plastic litter, as well as the current inexistence of valuable clean-up technologies make it seem inevitable that the abundance of plastic fragments will continue to increase in the years and decades to come. Owing to the low degradability of plastics, marine plastic debris is likely to persist for many centuries – even if input were stopped immediately.289

The current chapter will briefly summarize some findings on abundance and distribution of marine plastic litter (A), its composition (B), main sources (C) and impacts (D).

A Abundance and Spatial Distribution

About 10 per cent of all plastic wastes end up in the sea.290 Estimates reach from a daily input of around 27,000 tonnes and an annual input of 10 million tonnes to an annual input of 12.7 million tonnes of plastics to the ocean.291 Plastics make up 60–80 per cent of marine debris. They occur nearly everywhere in the world’s oceans, including polar regions, remote islands and the deep seabed.292 Geographical distribution and accumulation of the debris are not homogenous but strongly depend on ocean currents, winds, seasons and geomorphology, but also the proximity of urban settlements, shore use and other factors, including mass, buoyancy and persistence of the material.293 Since plastic materials are persistent and about 49–60 per cent of them are positively buoyant, many plastic objects travel long distances on ocean currents, including to remote places.294 Unless they are washed ashore and not retaken by the sea, and assumed that they are not consumed by animals or otherwise removed from the ocean, most objects will eventually become waterlogged or fouled by biota growing on their surface, which makes them heavy and causes them to sink.295 Marine litter is constantly exposed to external stresses that cause the items to fragment into ever-smaller pieces, including microplastics and possibly nano-sized particles. Particles of all sizes can be found in surface water, shallow waters, beaches and deep-sea sediments.296

i Floating Plastic Debris

In 2014, it was estimated that there were more than 5.25 trillion pelagic plastic particles floating in the oceans, with a total weight of about 268,940 tonnes.297 A 2018 study predicted about 1.8 trillion pieces of floating plastic debris, corresponding to at least 79,000 tonnes, inside an area of 1.6 million km2. The results of the study suggest that abundance of pelagic plastics have previously been underestimated and misinterpreted.298 Past and current input rates of plastics from land- and sea-based sources indicate concentration levels that exceed observed quantities by two orders of magnitude. There seem to be mechanisms either removing most of the plastic mass from the ocean surface or fragmenting them into smaller pieces that are not covered by the sampling methods. The fate of 99 per cent of marine plastic wastes thus remains unknown – a sobering number reflecting fundamental knowledge gaps with regard to the fate of microplastics in the ocean.299

The spatial distribution of floating plastic debris is governed by ocean currents. Ocean surface currents can be studied on the basis of data on traceable flotsam.300 The data on the release and recovery of the flotsam was used to develop and refine computer-based ocean current models, which predicted a number of debris accumulation zones, one of which is situated in the high-pressure zone between Hawaii and the US west coast. With the discovery of high amounts of plastic debris in this very zone by research vessels in the 1980s and late 1990s, first records of large plastic accumulation in a subtropical gyre have been established.301 In subsequent years, many sampling studies followed. They provided further evidence of the phenomenon, which is also taking place in other areas.302

Pathways of floating debris have also been studied by the use of data from satellite-tracked drifting surface buoys (drifters) as used, for instance, by the US National Oceanic and Atmospheric Administration’s (noaa) Global Ocean Drifter Program.303 Drifter data is used in global ocean circulation models that simulate input, transport and accumulation of floating debris in the ocean over a specific period of time. The models predict that ocean currents transporting debris tend to accumulate them in five different subtropical convergence zones or gyres in the North and South Atlantic Ocean, the North and South Pacific and the Indian Ocean, respectively (see Figure 11).304 Distribution patterns as revealed by sampling studies largely agreed with those predicted by the ocean surface circulation models.305

Figure 11
Figure 11
Accumulation zones of floating debris
judith schäli, ‘marine plastic pollution as a common concern of humankind’ in thomas cottier and zaker ahmad (eds), the prospects of common concern of humankind in international law (cambridge university press 2021) 161. reproduced with permission of cambridge university press through plsclear.

Gyres are spiralling ocean surface currents driven by the global wind system (see Figure 12). The currents tend to force the debris towards a central area, where debris concentration is elevated. A plastic particle or item which is released into the ocean is hence likely to be gathered with other plastic objects towards the centre of the convergence zones, after travelling for several years around the gyres.306

Figure 12
Figure 12
Ocean currents forming the five subtropical gyres
Author

The high incidence of plastic debris in the accumulation zones has been receiving increasing media attention during the last couple of years. The zones have commonly been called ‘plastic garbage patches’, ‘plastic soup’, ‘trash vortexes’ or ‘plastic islands’, although all of these terms are quite misleading. Most floating plastic items in the accumulation zones are small fragments that are barely visible. The zones are, therefore, not distinguishable on satellite images but have to be explored by sampling.

Marine biodiversity greatly varies from one gyre to another. The North Atlantic gyre holds the Sargasso Sea, a region of about four million square kilometres situated in the middle of the gyre. The Sargasso Sea is a hotspot for marine wildlife, as it contains a wide range of habitats and provides a resting, feeding and breeding area for many species.307 By contrast, the South Pacific gyre has been described as a desert zone, as its sediments belong to the least inhabited zones ever explored for evidence of life.308

Plastic accumulation in the North Pacific gyre is densest in two peak areas. The western peak is situated south-west of Japan; the eastern peak is located in the high-pressure zone between Hawaii and the United States. Exact venue and size of the accumulation zones are difficult to determine, as they constantly vary. Sampling studies and circulation models suggest that the eastern accumulation zone in the North Pacific Ocean is the biggest and densest ‘patch’. Its surface area is about 1.6 million km2.309

Several sampling studies have been undertaken in different regions and time frames.310 Sampling studies use different methods to estimate the abundance of floating plastic debris. The quantity of larger items can be extrapolated from visual observations and counting, while the abundance of smaller items is generally estimated by means of samples collected with net trawls. Two of the studies are global in scope.311

There are only a few datasets spanning more than a decade. Yet, studies overall suggest that there was a dramatic increase in marine plastic debris of more than 20 millimetres until the 1990s. Since then, quantities of pelagic plastic debris of measurable sizes seem to have stabilized in the Northern Hemisphere.312 It remains unclear whether this is due to sedimentation, shore deposition, ingestion by marine organisms or fragmentation to smaller debris sizes that were not retained by the sampling nets.313 Data moreover suggest that accumulation rates in the Southern Hemisphere are slightly lower than in the Northern Hemisphere, but still increasing significantly (see Table 3).314 A study from 2012 modelling the pathways of surface marine debris for a period of more than 1,000 years suggests that, over the centuries, exchanges between the ocean basins play an important role in the spreading of marine debris, and stabilization takes several centuries.315

Table 3
Estimates of total abundance and mass of floating plastic debris in different oceanic regions

Abundance (pieces)

Mass (t)

North Pacific Ocean

1,990,000,000,000

96,400

North Atlantic Ocean

930,000,000,000

56,470

South Pacific Ocean

491,000,000,000

21,020

South Atlantic Ocean

297,000,000,000

12,780

Indian Ocean

1,300,000,000,000

59,130

Mediterranean Sea

247,000,000,000

23,150

Total

5,255,000,000,000

268,940

data source: marcus eriksen and others, ‘plastic pollution in the world’s oceans: more than 5 trillion plastic pieces weighing over 250,000 tons afloat at sea’ (2014) 9 plos one e111913, 8.

Plastic debris does not only occur within the five gyres but is ubiquitous and can be found across all the oceans from Arctic to Antarctic regions. High occurrence has been observed in enclosed and semi-enclosed seas, including the Mediterranean Sea,316 the North Sea,317 the Barents Sea318 and northern South China Sea.319 Estimations of global total weight of floating plastic debris lie at 233,400 tonnes for larger plastic items and 35,540 tonnes for microplastics.320

Overall, litter is more abundant close to cities and tourist beaches, which are important sources of discarded bottles, shopping bags and cigarette filters, napkins and other consumer goods.321 Yet, since plastic litter travels long distances more easily than other debris, the share of plastics from total debris increases as the distance from the debris source increases.322 Also, average density increases towards the centres of the accumulation zones, as predicted by the simulation models. In general, ocean margins are areas of plastic migration, while subtropical gyres are areas of accumulation.323 In the centre of the gyres, pieces tend to be smaller, older and more weathered.324

ii Plastic Debris in Beaches

It is estimated that about as much plastic particles that are afloat in the oceans are washed ashore.325 Plastic debris is, hence, commonly found in beaches and beach sediments all around the world. The abundance of beached plastic litter has been studied in different regions, including in the North Atlantic,326 the North Pacific327 and the Southern Hemisphere, especially the beaches and shores of New Zealand.328 Observed numbers greatly vary, depending on the survey technique, accounted fragment sizes and location.329 High densities can be found close to sources, after flooding events or container spills.330 Some of the highest densities of debris was reported from Henderson Island, a remote, uninhabited island in the South Pacific. Although the island is far away from any kind of input sources, an estimated 37.7 million debris items weighing a total of 17.6 tons were present on Henderson in 2017, with up to 26.8 new items per metre accumulating daily.331 Coast sediment-surface counts do not take into account buried litter and, hence, underestimate abundance.332

The main sources of beach litter are land-based, originating from both adjacent and distant countries.333 Accumulation is greater near densely populated areas and on beaches that are frequently visited.334 Other factors that influence the accumulation of debris in coastal areas include the shape of the beach and geographical location.335 Relatively high densities of plastic debris, but also high variability, can be found in enclosed or semi-enclosed seas, as well as in open-ocean coastlines such as Hawaii. Changes in oceanic circulation driven by weather phenomena such as El Niño events increase inter-annual variability.336

As is the case for floating plastic debris, cleaning of beached plastic debris is extremely difficult, especially with regard to small size fragments and buried pieces. While beach clean-up days are organized around the world, success is limited, as more debris is washed ashore on a daily basis.

iii Plastic Debris on the Seabed

A possible explanation for the missing fraction of plastic debris in open-ocean surveys lies in the particles’ tendency to travel towards the ground. Approximately 70 per cent of all floating plastic fragments are believed to eventually sink to the seabed.337 A reason for their sinking is the weight of fouling by bacteria, algae, barnacles, shellfish and other organisms. Fouling may increase the density of plastic objects, causing them to sink, with particles being redistributed throughout the whole water column. When ingested, microplastic particles might also sink with the bodies of dead fish or with faecal pellets.338

The deep-sea sediments have shown to be a major sink for plastics, including microplastics.339 Settling of plastic litter on the deep-sea bed seems to be permanent in most cases.340 If, however, the biological surface layer is removed by grazing organisms or reduced due to adverse conditions for the fouling organisms in the depths, the objects may float upwards again.341 Investigation of the presence and abundance of plastic particles in the deep sea, as well as of their aging, is hampered by sampling difficulties and high costs. Large-scale studies on seabed debris are, hence, scarce.342 It is widely assumed that plastic objects or fragments degrade at much lower rates at the seafloor, where they are shielded from uv radiation. However, some plastics may be susceptible to bacterial decay at sea.343

It is assumed that bottom debris, including from land-based sources, tends to become trapped in areas of low circulation, especially bays and semi-enclosed seas.344 Studies suggest that in the North Sea, a total of 600,000 m3 of marine debris is present on the seabed.345 High densities of marine debris, particularly plastic, have also been found on the Mediterranean seabed.346

B Composition of Marine Plastic Debris

While plastics constitute only about 12 per cent of global municipal solid waste mass, they constitute about 60–80 per cent of total marine debris.347 Plastic debris is often categorized into different size classes, including nano-, micro-, meso-, macro- and megadebris.348 Microplastic fragments of sizes up to 4.75 mm are predominant in terms of numbers, with trillions of them floating in surface waters. In terms of mass, however, they only represent about 13 per cent of the total available buoyant material.349 The average size of plastic particles in the marine environment seems to be decreasing, while the abundance and global distribution of microplastics have increased over the last few decades.350 Microplastics comprise primary microplastics (such as microbeads351 from cosmetic products, abrasives or pellets) and secondary microplastics, consisting of fragments, fibres or powders breaking from bigger objects. Abrasion of tyres is considered the largest source of microplastics, followed by city dust, abrasion of road markings and releases due to the laundry of synthetic textiles.352 Owing to their high numbers and small size, microplastics are almost impossible to be removed from the environment.353

The vast majority of floating objects are made of pe and pp rigid plastics and bundled fishing nets and ropes. Foamed ps items also belong to the most commonly occurring marine macroplastics. Derelict fishing buoys are important contributors in terms of weight.354 By contrast, denser types of plastic, such as pet, tend to sink more readily.355 Studies moreover suggest that the objects’ volume-to-surface ratios play a significant role for their movement patterns and fate. Objects such as films, which have small volume-to-surface ratios, seem to be more susceptible to biofouling and therefore to sink more rapidly or fragmentize into microscopic pieces that are removed from surface layers.356

The most commonly found plastic litter items in the marine environment, especially beaches, include cigarette butts, plastic beverage bottles and bottle caps, food wrappers, plastic grocery bags and other bags, plastic lids, straws and stirrers, foam takeaway containers, and plastic cups and plates.357 Plastic pellets or nurdles are also commonly found on beaches and water surfaces all over the world.358 User plastics are predominant near densely populated areas. Abandoned, discarded or lost fishing gear is prevalent in offshore places.359 In particular, abandoned fishing nets and ropes are common in many places.

C Main Pollution Sources

From a regulatory point of view, a distinction is often drawn between ocean- or sea-based pollution sources on the one hand and land-based sources on the other hand. Ocean-based sources of marine pollution include deliberate dumping of wastes at sea (that is, from vessels, aircraft or offshore installations) and disposal or accidental loss of wastes, cargo and gear by commercial and recreational shipping, fishing and military fleets. In particular, derelict fishing nets and ropes, as well as container spills are important sources of marine plastics. Sea-based sources also include wastes resulting from other sea-based activities (including from the aquaculture industry, offshore platforms and other installations at sea).360

Land-based pollution sources, on the other hand, consist of municipal, industrial or agricultural wastes or discharges, as well as dumped wastes or otherwise irregular waste streams that reach the marine environment from land through different pathways, including rivers, severe weather events such as floods, and wind.361 Marine debris from land-based sources typically includes beach and urban litter, wastes from unprotected landfills that are located near the coast, sewage outflows and storm water drainage outlets.362 Pollution through the atmosphere that results from land-based activities is usually also counted as land-based pollution (e.g. atmospheric deposition of microplastics from tyre wear and from wear and tear of plastic products during normal use).363

Land-based sources account for about 80 per cent of marine pollution, with sewage being the largest source of contamination.364 Similarly, it is widely cited that about 80 per cent of marine plastic debris stems from land-based sources.365 The portion of plastics from land-based sources tends to be lower in offshore places, where marine-sourced plastics are often predominant. This might be due either to the latter’s purposely engineered durability in the marine environment or the fact that plastics entering the ocean from land-based sources often accumulate in coastal environments, including through beaching.366

A distinction can also be made between point sources of pollution, referring to sources with a single, geographically identifiable entry point into the environment, and non-point sources, which are much more diffuse. Main point sources of anthropogenic pollutants include industrial plants, sewage discharges and storm water runoff, as well as offshore platforms. The more problematic (mainly) non-point sources include agriculture, forestry and development activities, maritime transportation and dumping.

Plastic input into the sea from land is mainly caused by improper material, product and waste management, improper human behaviour, including littering, unsustainable production and consumption patterns, involving the wide use of single-use plastic goods, and unintentional losses during use, especially due to the abrasion of products.367 Plastic debris from land-based sources includes plastics from all life-cycle stages, including pre-production resins or nurdles, user goods and plastic wastes. A high number of activities contribute to marine plastic pollution from land-based sources, including industrial activities, sewage, urban development and tourism. Key sources of primary microplastics in the marine environment are plastic pellets, synthetic textiles, tyres, road markings, city dust and personal care products. Most of these sources generate unintentional losses through abrasion, weathering or unintentional spills during production, transport, use or disposal. Only losses from personal care products, such as toothpastes or shampoos, can be considered intentional losses.368 Households activities generate about 77 per cent of microplastics releases, especially through passenger transport in private cars, laundry of synthetic textiles and the use of personal care products.369

It has been estimated that, in 2010, 275 million tonnes of plastic waste were generated in 192 coastal countries, with 4.8 to 12.7 million tonnes entering the ocean.370 Main contributors in terms of land-based sources of marine plastic debris are countries with large coastal populations, widespread use of plastic goods and packaging, and high rates of mismanaged wastes. Mismanaged waste includes disposal in dumps or open, uncontrolled landfills. Such waste potentially enters the ocean via inland waterways, wastewater outflows, and transport by wind or tides.371 If the share of mismanaged wastes cannot be diminished, plastic input to the oceans is expected to rise significantly, since coastal population is increasing.372

Sixteen of the top 20 polluters are middle-income countries with fast economic growth but lacking essential waste management infrastructure. Several East and South East Asian countries rank among the top ten polluters.373 Studies suggest that effective input reduction would require substantial infrastructure investment primarily in low- and middle-income countries, as well as a reduction in waste generation in higher-income countries.374

D Impacts of Marine Plastic Pollution

i Impact on the Marine Environment and Marine Biodiversity

Marine plastic litter is known to cause physical hazard to marine wildlife. An estimated 817 marine species are directly affected through ingestion of plastics and microplastic particles, entanglement in marine debris, ghost fishing by derelict fishing nets or ropes, dispersal by rafting on marine debris, especially plastics, and provision of new habitats due to marine littering.375 Marine plastics affect marine organisms at every trophic level, from small filter-feeding organisms at the bottom of the food chain to marine mammals such as whales.376 Effects can be observed in all different kinds of marine habitats, including coastal habitats, the seabed and open waters.377 They can also be observed in remote locations with negligible local sources of plastics. Most of observed and reported impacts occur at suborganismal levels (e.g. molecular, cellular, tissue). However, lethal effects on individual organisms have also been widely observed.378 Impacts on populations, assemblages and species are more difficult to quantify but cannot be excluded.379

Wildlife entanglement is one of the most visible effects of marine debris (see Figure 13). Entangled animals are hindered in their ability to move, feed and breathe. They may not be able to avoid predators or may die from exhaustion. Wounds from entanglement can inflame and thus bring some additional risk. One hundred per cent of marine turtle species, 67 per cent of seal species, 31 per cent of whales and 25 per cent of seabird species have been recorded as entangled. Of a particular concern in this respect are derelict fishing gear, especially nets that continue to trap and kill organisms (ghost fishing) and damage benthic habitats, but also ropes, balloons, plastic bags, sheets and six-pack drink holders.380

Figure 13
Figure 13
Turtle entangled in marine debris
noaa marine debris program, ‘entangled green sea turtle’ (2012) <https://www.flickr.com/photos/noaamarinedebris/7656597150/> accessed 19 February 2022, licensed under cc by 2.0, <https://creativecommons.org/licenses/by/2.0> accessed 19 February 2022.

Ingestion of marine debris is a less visible but widely reported phenomenon (see Figure 14).381 A broad range of marine species ingest marine plastic debris intentionally – because they mistake the particles for food – or unintentionally, by filter feeding or via their prey (secondary ingestion).382 Offshore-feeding birds such as fulmars and albatrosses have been found to contain plastic objects in their guts and pass them on to chicks.383 When accumulating in the stomach, plastics affect the organism’s fitness and may have consequences for reproduction and survival. Ingestion of plastics has been documented for 100 per cent of marine turtle, 59 per cent of whale, 36 per cent of seal and 40 per cent of seabird species.384 In some species, ingestion is reported in over 80 per cent of a population sampled.385 Plastics in the digestive tract often contribute to malnutrition and dehydration. They may block the gastrointestinal tract or severely damage it, with possible lethal effects.386 Implications of marine plastic litter for invertebrates and other species with low public focus on are less well studied.387

Figure 14
Figure 14
Ingestion of marine plastic debris. The unaltered stomach contents of a dead albatross chick photographed on Midway Atoll in the Pacific in 2009 include plastic marine debris.
© 2009 Chris Jordan. Reprinted with permission by Chris Jordan.

Marine plastic debris not only poses physical hazards through entanglement or ingestion but also chemical hazards with potential toxicological impacts on marine ecosystems and biodiversity. Plastics can leach chemicals that have been added during production or are by-products of the production process. Some of these leaching chemicals have potential negative health effects.388 In addition, plastic debris tend to accumulate chemicals, including persistent, bioaccumulative and toxic substances,389 from the surrounding seawater. Persistent organic pollutants can become several orders of magnitude more concentrated on the surface of plastic debris than in the surrounding seawater.390 As a result, marine plastics may transfer a complex mixture of potentially hazardous chemicals to the tissues of organisms upon direct ingestion or via the food web.391 The chemicals can penetrate cells and harm ecophysiological functions performed by organisms, for instance by increasing liver toxicity or disrupting the endocrine system.392 It has been shown that these contaminants are bioavailable to a wide range of marine species, including whales, sharks, seabirds, fish and other organisms upon ingestion.393 Plastics cause and enhance bioaccumulation of such chemicals in animal tissues, including in a range of commercially important fish and shellfish.394 Toxicant concentrations potentially increase through transfer within the food web (biomagnification). Studies of seafood, sea salt and other products intended for human consumption suggest that humans are also affected.395 More research is needed on potential effects on humans and other non-marine mammals.396

Plastics may also serve as a vector for chemicals by absorbing chemicals in contaminated areas and leaching them in more pristine regions, with unknown effects on local ecosystems in these areas.397 Floating plastic debris also facilitates transport of microorganisms, pathogens and other plant and animal species. It may thereby contribute to increased invasion of ecosystems by alien species. The dispersal of organisms related to floating plastic debris takes place horizontally, from one region to another, and vertically, through the water column to the seafloor. Biological invasions by non-indigenous species are considered a major threat to coastal ecosystems. While so-called ‘hitch-hiking’ also occurs on natural floating debris, marine plastic litter substantially enhanced rafting opportunities for marine organisms. It is widely assumed that change in the temporal and spatial availability of rafts dramatically affects the dynamics of rafting transport and colonization by associated organisms.398

Plastic debris may also cause habitat alterations. When accumulating on the seafloor, it reduces the available oxygen content of the water, with detrimental effects for aerobic benthic organisms – a phenomenon that is often referred to as smothering.399 When accumulating on beaches, it potentially alters graininess, density and permeability of the sediment. Microplastic contents in sediments also reduce heat transfer, causing the sediments to warm more slowly or reach lower maximum temperatures. It has been assumed that these changes can have a serious effect on beach organisms, including those that have temperature-dependent sex-determination, such as sea turtle eggs.400

ii Economic and Social Impacts

Marine plastic pollution entails considerable costs that are related to the clean-up of litter, to the reparation and replacement of damaged ship components and gear, to health impacts (including costs of emergency rescue services due to physical or navigational hazards of plastic debris and hospitalization costs), and to the reduction of ecosystem services (including food provision) and other economic benefits derived from the marine environment. Marine litter-related costs include costs related to additional expenditure and costs related to losses of output and revenue, as well as social or welfare costs, which are generally associated with broader health impacts and the reduction of aesthetic, recreational, cultural or other intangible values of marine environments.401 Not all of these costs are easily quantifiable in financial or economic terms. Quantifications thus usually do not reflect full costs. The total natural capital cost of plastic used in the consumer goods industry is estimated to be more than US$75 billion per year.402 Global costs related to marine litter have been estimated at US$13 billion per year.403 These costs are partly borne by a broad range of industry sectors – including the shipping and fishing industries, tourism, aquaculture and agriculture – and partly by municipalities and the public at large.

Clean-up costs include costs for the collection, transportation and disposal of litter and the construction and maintenance of waste management infrastructure, as well as related administrative costs. They are mostly borne by coastal municipalities, tourism companies or privately organized voluntary groups. In 2010, coastal municipalities in the UK spent about €18–19 million in total for cleaning up beaches from marine litter. Yearly costs seem to be increasing considerably.404 In Belgium and the Netherlands, municipalities incur beach clean-up costs of about €10.4 million per year.405 Local communities relying on coastal tourism often have to bear additional costs in the form of loss of revenue or income when marine litter affects people’s perceptions of the quality of the marine environment and causes numbers of visitors to decline. The economic impact of a single marine litter event in South Korea in 2011 was estimated to be between €23 and €29 million as a result of over 500,000 fewer visitors when compared to 2010.406 The loss can affect national economies and level of employment when dependent on coastal tourism and associated economic activities.407 Coastal municipalities, governments and local communities also often spend money for awareness-raising activities and education in order to address littering and other behavioural sources of marine plastics.

Much like coastal tourism, fisheries and, to a lesser extent, the aquaculture industry are extremely vulnerable to the hazards posed by marine litter. In the Asia-Pacific region, marine litter costs more than US$1 billion per year to marine industries, equivalent to 0.3 per cent of the gross domestic product for the marine sector of the region.408 Economic impacts are related to reparation and replacement costs of vessels and gear damaged due to encounters with marine litter, as well as lost fishing opportunities due to time spent cleaning litter from nets, propellers and blocked water intakes.409 Marine litter costs the Scottish fishing industry the equivalent of 5 per cent of the total revenue of affected fisheries.410 In addition, fisheries suffer from a loss of revenues due to reduced or contaminated catches. Ghost nets especially can contribute to a decline in fish stocks. The introduction of alien invasive species or pathogens with plastic flotsam can result in serious economic losses, too.411 Economic impacts that are related to a loss of fish or shellfish quality due to plastic ingestion and contamination have not yet been properly assessed.

As a significant navigational hazard for vessels, marine litter also considerably affects the shipping and yachting industries. In order to keep their facilities safe and attractive, harbours have to constantly remove marine litter. Vessel incidents related to the obstruction of motors due to plastics or interferences with propellers, anchors, rudders or blocked intake pipes and valves are more and more common.412 Collisions with marine litter also poses a threat to mariners.

When ocean debris is blown to or washed upon coastal farmland, it may also affect agriculture. It may cause damage to property and equipment or present a risk to livestock.413

The costs related to marine plastic pollution are considered avoidable losses to the economy to the extent that prevention of marine plastic litter can reduce such costs.414 It is assumed that costs of inaction are often higher than costs of action.415 Action against marine litter can be taken throughout the life cycle of plastics in the form of either preventive or remedial measures. The two types of measures are complementary. However, prevention in the form of systemic upstream approaches have been identified as more efficient and effective when compared to mere remedial actions such as litter removal. They are also more cost-effective in the long run.416

The question of who has to bear the costs related to marine plastic pollution raises a number of equity concerns, both with regard to intra- and intergenerational equity (referring to equity within a generation and between generations, respectively).417 The intragenerational aspect is related to the fact that costs associated with marine plastic debris are not necessarily borne by those who cause the problem in the first place.418 On the one hand, producers and users of plastic goods do usually not have to fully bear the costs related to these products and the damage they cause when released into the environment. Costs in the form of negative externalities of such products are borne by others, including the different actors as discussed in the prior paragraphs. On the other hand, the level at which countries are affected by the issue is highly uneven. It depends on a country’s geographic location, national economy and level of income. Developing countries, and especially small island developing countries, are generally most affected, even though their contribution to the problem may be negligible. From an intergenerational perspective, it is important to note that the full dimension of the consequences, including economic, of marine plastic litter may only be revealed in the future. It is conceivable that costs related to currently existing levels of plastic pollution will increase over time and be borne by future instead of current generations.

In order to respond to such equity concerns, a number of measures seems necessary. From an international law perspective, an appropriate response involves the whole international community. Cooperation among the countries, including all the polluters and both countries with weak waste management infrastructures and technologically advanced countries, seems inevitable in order to find common responses. Technological and financial support of countries in need seems a necessary feature for such a response. From an industry perspective, costs would have to be internalized and thus be fully borne by the polluters. Possible approaches and instruments allowing for cost internalization are discussed in Part 1.419

3 Summary and Interim Conclusions

Plastics, as we know them today, are a relatively young material. During their rather short history, a great number of scientists, entrepreneurs, inventors, discoveries, events and coincidences, as well as a considerable amount of both endeavour and serendipity contributed to their development. The history of plastics was shaped by the pursuit of power in imperialistic times and during wars, by economic drivers and profit-related motives, but also by an inexhaustible desire for knowledge and discovery, the joy of experimenting and the wish for well-performing, easily processible materials that are not only affordable but allow new designs and applications which were not imaginable before. Plastics reflect the inventiveness of their developers in their extreme versatility. In some regards, they outstripped natural materials in their performance, and played a decisive role in the development of modern communication, transportation and space technologies, as well as in housing, sanitation and alimentation.

Along with rising income levels and new economic models, plastics also considerably influenced our production and consumption patterns and have become an integral feature of the consumer society – a society which is increasingly reflecting on the consequences of waste proliferation, both within society and beyond. Public awareness of the risks and costs of wastes, and plastic wastes in particular, is rising. The accumulation of plastics in remote areas, including the high seas and the deep seabed, triggers feelings of indignation and concern. In these places, and out of human surveillance and control, the downside of many of the outperforming characteristics of plastics is revealed: their high degree of biological inertness, the toxic or ecotoxic effects of some of their components or additives and, above all, their sheer abundance.

As shown in Part 1, pollution in the form of marine plastic debris and microplastics brings about a particular set of challenges and hazards that are unknown to other forms of marine pollution. Plastic debris barely degrades and is difficult to clean up with current technologies. With continuous input from land and, in a more limited way, from sea-based sources, plastic litter is rapidly accumulating in the oceans. Projected scenarios with regard to quantities and impacts are alarming.420 When compared with other forms of marine pollution, marine plastic debris spreads more easily and more widely. Plastic fragments from nano to macro sizes can be found across the oceans and occur in all compartments of the sea, including surface waters, pelagic waters, beaches and the seabed. Notably, open-ocean accumulation zones are often situated in areas beyond national jurisdiction. Plastic fragments serve as a vector for contaminants and pathogenic microorganisms, facilitate the dispersal of invasive species, and affect a wide range of marine species and ecosystems. Moreover, marine plastic pollution affects national economies, poses a threat to human health, and impedes legitimate uses of the sea, including marine transportation, fishing and recreation. Coastal zones, many of which may be considered biodiversity hotspots, are probably the most vulnerable to the negative impacts of plastic debris. Yet, plastics are ubiquitous in the ocean. While marine plastic pollution certainly poses a problem to local families and communities, its scope is far wider than that. It is, indeed, a global problem, calling for responses at various levels of governance, from local to global.

Part 1 has also shown that the bulk of marine plastic pollution stems from land-based sources. It mainly includes mismanaged wastes, including from urban centres and dumping sites situated close to the coast or from tourist beaches. Single-use plastic items, such as bags, cups, bottles, films and cutlery, represent a large proportion of the wastes encountered in marine environments, especially coasts. Plastic pollution from land-based sources also includes primary and secondary microplastic particles from tyre wear, city dust, cosmetics, plastic production, laundering and other sources and activities. The particles and fragments, both micro and macro, enter the marine environment from the land through rivers, tides, floods, winds, sewage outflows or the atmosphere.

Costs related to marine plastic pollution are not necessarily borne by the ones who cause them. There are many complicating factors in the establishment of a causal link between the production, use or disposal of plastic products and any consequential loss or damage that may occur in the marine environment. Comparable to the emission of greenhouse gases and the related impact of global warming, the release of plastic particles into the environment (and the marine environment in particular) from land is continuous, dispersed and diffuse in character. The complex life cycle of plastic products suggests that the many actors involved in it share a potential responsibility. Due to the wide dispersal, complicated distribution patterns and continuous fragmentation processes of marine plastic debris, it is usually difficult to trace it back to its exact source when harm occurs. However, a collective responsibility is incontrovertible, while the degree to which a specific country or private actor contributes to the problem is highly variable and difficult to measure.

Marine plastic pollution entails high environmental, social and economic costs that are potentially irreversible and (at least partially) avoidable. With the exception of incinerated plastics, almost every piece of plastic ever made and released into the environment still remains there in the form of whole items or as fragments – and poses a potential risk to the marine environment.421 Plastic production is gradually rising, while the average service life of plastic products has continually decreased in the last years. As a consequence, plastic waste generation rates continue to grow. Plastic accumulation in the seas will not stop or slow down until there is a change not only in perception but in action by all the actors involved: governments, producers, consumers and waste management operators.

A change in action may require, or be facilitated by, a change in policies and law. While the legal aspects and possibilities will be examined in the next part, the insights as provided by Part 1 give some guidance with regard to the direction in which such a change may go in order to contribute to a solution. It can be expressed in targets at which potential legal adjustments should aim:

  1. consumer responsibility: a change in consumption habits, including through more reasonable, needs-based consumption; gradual substitution of durable products for disposable ones; lower packaging consumption; thorough waste separation at disposal; extended user responsibility;
  2. producer responsibility: green design, including product design for a longer service life and recyclability; life-cycle-based approaches in material selection; no obsolescence; declaration of materials and additives; use of safe chemicals only; reduced packaging where possible; cost internalization; extended producer responsibility;
  3. sustainable resource management: considering new economic models, approaching a circular economy; revalorization of resources and their reintroduction into the production and consumption cycles through reuse, recycling and composting; integrative waste management, including waste prevention, waste reduction, effective waste collection systems with cost recovery and safe waste disposal with energy recovery, if possible. In particular, the improvement of waste management infrastructure in developing countries seems of paramount importance but will require substantial resources and time.422

The cumulative and indirect nature of the risk associated with the production, use and disposal of plastics, the diffuseness of this form of pollution and its global scale are important characteristics. They need to be given particular attention in the analysis of the legal and policy framework that applies to the problem. Part 2 will give an overview of this very framework and the relevant rules at global and regional levels, as well as their implementation at the national level. Insights from Part 1 suggest that with respect to marine plastic pollution from land-based sources, such implementing measures need to address waste and resource management in the first place, as well as unsustainable production and consumption patterns. The wide and improvident use of disposable or non-recoverable items plays an important role in this regard and calls for particular attention.

22

See Don V Rosato, Marlene G Rosato and Nick R Schott, Plastics Technology Handbook Volume 1 (Momentum Press 2010) 10. cf Dietrich Braun, Kleine Geschichte der Kunststoffe (Carl Hanser Verlag 2013) 5 and 12.

23

Braun (n 22) 29.

24

The words poly- and monomer are derived from the Greek polys, meaning ‘many’, monos, ‘one’, and meros, ‘part’ or ‘unit’: see ‘Polymers’, University of Chicago (ed), Encyclopaedia Britannica, vol 14 (15th edn, 1977) 764.

25

Rosato, Rosato and Schott (n 22) 10 and 22. The number of monomers within a polymer is highly variable. Some synthetic polymers have hundreds of thousands of repeat units: see Donald L Burdick and William L Leffler, Petrochemicals in Nontechnical Language (4th edn, Pennwell Books 2010) 13. The polymerization of different monomers (that is to say, the linking of molecules with different chemical structures to a single sort of macromolecules) is generally referred to as co-polymerization: Braun (n 22) 29.

26

Meikle (n 1) 5.

27

‘Plastic’, in Jan W Gooch (ed), Encyclopedic Dictionary of Polymers (Springer New York 2011) 540–41.

28

See Braun (n 22) 32.

29

In a broad sense, the term is used to ‘designate any polymer that is a basic material for plastics’: ‘Resin’, in Gooch (n 27) 624. The term may, however, also refer to ‘any of various solid or semisolid amorphous fusible flammable natural organic substances that are […] formed especially in plant secretions, are soluble in organic solvents (as ether) but not in water, [and] are electrical nonconductors’: Merriam-Webster Online Encyclopaedia, ‘Resin’ (2019) <http://www.merriam-webster.com/dictionary/resin> accessed 19 February 2022. Examples for natural resins include amber and shellac, both of which have properties comparable to the ones of synthetic plastics.

30

Each element can (and wants to) link with a fixed number of other atoms of the same or another kind. This specific number is called valence. Carbon has a valence of 4, generally binding itself to four other atoms. In methane (ch4), the carbon atom is linked to four hydrogen atoms. In ethane (C2H6), the two carbon atoms are linked to each other and to three hydrogen atoms each, which amounts to a valence of four. In cases where a carbon atom cannot bind itself to four other atoms, it will form double, or even triple bonds in order to satisfy its valence of four (such as in ethene (H2C=CH2) or acetylene (H–C≡C–H)). Compounds in which there are only single bonds are called saturated. Compounds with double or triple bounds are unsaturated. They are, as a general rule, more reactive than saturated compounds, since double and triple bonds are weaker than single bonds: see Burdick and Leffler (n 25) 4; Hans Domininghaus, Die Kunststoffe und ihre Eigenschaften (Peter Elsner, Peter Eyerer and Thomas Hirth eds, Springer 2005) 22.

31

The molecular weight of a substance corresponds to the sum of the atomic weights of all the atoms in a molecule. For more information, see Walter Gratzer, Giant Molecules: From Nylon to Nanotubes (Oxford University Press 2009) ch 1.

33

Rubber, as occurring in nature, mainly consists of long chains of isoprene (also called 2-methyl-1,3-butadiene) and water. It can be found in (or produced of) the juice of specific sorts of trees. Rubber trees exude a milky liquid when their tissue gets hurt. When exposed to air, the liquid, or latex, partially coagulates and gets rubbery. Coagulation of latex can be enhanced by adding certain substances such as formic acid, which is usually done in modern rubber plantations: see Harry Linn Fisher, Rubber and Its Use (Chemical Publishing 1941) 25–31. The most common form of polymerized isoprene is cis-1,4-polyisoprene: see Jerry Bush and others, ‘Synthetic Polyisoprene (IR)’, The Vanderbilt Rubber Handbook (14th edn, rt Vanderbilt 2010) 57–67.

34

About 90 per cent of all chemicals used in the chemicals industry are derived from petroleum. The produced substances have an extremely broad range of applications. The share of petroleum used in plastics amounts to about 5 per cent of global petroleum consumption: see Maurice Reyne, Plastic Forming Processes (John Wiley & Sons 2013) 2.

35

See Rosato, Rosato and Schott (n 22) 22.

36

For more information about the production of synthetic polymers and plastic feedstock, see Burdick and Leffler (n 25) ch 2; Mohamed A Fahim, Taher A Al-Sahhaf and Amal Elkilani, Fundamentals of Petroleum Refining (Elsevier 2009); James H Gary and Glenn E Handwerk, Petroleum Refining (crc Press 2001); Moore and Phillips (n 3) 25; Reyne (n 34); Paul R Robinson, ‘Petroleum Processing Overview’ in Chang S Hsu and Paul R Robinson (eds), Practical Advances in Petroleum Processing (Springer New York 2006).

37

The monomer of polyethylene is called ethene or ethylene, which can be derived from ethane. It belongs to the hydrocarbons, a group of carbon molecules consisting of just carbon and hydrogen. The prefix eth– indicates that the longest carbon chain counts two carbon atoms. The suffix –ane is used when there are just single bonds between the individual atoms. Other members of this group of hydrocarbons are methane (CH4) (meth– referring to one carbon atom), and, accordingly, propane (C3H8), butane (C4H10), pentane (C5H12), hexane (C6H14) and so on. The structural formula of these compounds is very similar, except for the increasing number of carbon atoms in the backbone chain. Because they have just single bonds, methane, ethane, propane etc. belong to the family of alkanes, which are also called paraffins, or saturated hydrocarbons. The general formula of alkanes/paraffins is CnH2n+2. By contrast, the suffix –ene is used when there is at least one double-bond within a chain. Alkenes, such as ethene, propene, butene, pentene etc., are also known as olefins. Polyethylene, which is made from polymerized ethene, thus belongs to the family of polyolefins: see Gratzer (n 31) ch 2; Burdick and Leffler (n 25) 3.

38

See JA Brydson, Plastics Materials (7th edn, Butterworth-Heinemann 1999) 19.

39

See Braun (n 22) 30–32.

40

See Brydson (n 38) 23.

41

See Braun (n 22) 31.

42

ibid 32.

43

‘Engineering Plastic’, in Gooch (n 27) 269. Polyamides and polycarbonates belong to the most important groups of engineering plastics. Ultra-high-molecular-weight polyethylene, acrylonitrile-butadiene-styrene (abs), polytetrafluoroethylene (ptfe, better known under its commercial name Teflon) and polyoxymethylene (pom), as well as many different kinds of (glass-) fibre reinforced or otherwise enhanced plastics also belong to this group.

44

The term high-performance plastics exclusively refers to thermoplastic materials, such as polyphenylene sulphide (pps), polyethersulfone (pes), polysulfone (psu), polyether ether ketone (peek), polyetherketone (pek) and polyetherimide (pei). Some of these materials are obtained by dubbing unreinforced engineering plastics: see ‘Engineering Plastic’, in ibid 269. See also ‘Advanced Resin’, in ibid 21.

45

See Anthony L Andrady and Mike A Neal, ‘Applications and Societal Benefits of Plastics’ (2009) 364 Philosophical Transactions of the Royal Society B: Biological Sciences 1977, 1977; Martin F Lemann, Waste Management (Peter Lang 2008) 106; Donald V Rosato, MG Rosato and Dominick V Rosato (eds), Concise Encyclopedia of Plastics (Springer Science & Business Media 2000) 415. Besides their traditional names, polymers usually have a structure-based and a source-based name. For the purpose of this book, the traditional names are preferred to the more technical ones. They do not necessarily correspond to the ones as recommended by the International Union of Pure and Applied Chemistry (iupac), an international scientific body that is largely recognized as an authority on chemical nomenclature and terminology: see International Union of Pure and Applied Chemistry, Compendium of Polymer Terminology and Nomenclature: IUPAC Recommendations, 2008 (rsc Pub: iupac 2009) 259–60. The abbreviations pe, pp, pvc, ps and pet are based on the 2001 International Standard iso 1043-1:2001.

46

They have a common chemical structure of CH2=CH–R, where R stands for a hydrogen atom (ethene), a methyl group ch3 (propene), a chlorine (vinyl chloride) or a phenyl group (styrene): Burdick and Leffler (n 25) 277; Domininghaus (n 30) 26. For the vinyl group (CH2=CH–) as a common structure in their monomers, the corresponding polymers (pe, pp, pvc and ps) belong to the so-called vinyl plastics. In plastics literature, however, the term is most often used in reference to polyvinylchloride and its copolymers only: see Gooch (n 27) 795–96. pet is made from ethylene glycol and either dimethyl terephthalate or terephthalic acid.

48

See ASTM D7611/D7611M-21, ‘Standard Practice for Coding Plastic Manufactured Articles for Resin Identification’ (2021).

49

See, for instance, Michael Tolinski, Plastics and Sustainability: Towards a Peaceful Coexistence between Bio-Based and Fossil Fuel-Based Plastics (John Wiley & Sons 2011); Troy A Hottle, Melissa M Bilec and Amy E Landis, ‘Sustainability Assessments of Bio-Based Polymers’ (2013) 98 Polymer Degradation and Stability 1898.

50

For a discussion on (bio-)degradability of plastic materials, see Section 1.1.B.i below. See also Madeleine R Yates and Claire Y Barlow, ‘Life Cycle Assessments of Biodegradable, Commercial Biopolymers – A Critical Review’ (2013) 78 Resources, Conservation and Recycling 54.

51

See Hans-Josef Enders and others, ‘Biopolymers as a Source of Energy’ (2010) 8 Kunststoffe 83, 83; unep, Biodegradable Plastics & Marine Litter: Misconceptions, Concerns and Impacts on Marine Environments (unep 2015) 16.

52

See Brydson (n 38) 124.

53

See Hans-Georg Elias, Makromoleküle: Band 4: Anwendungen von Polymeren (4th edn, John Wiley & Sons 2003) 17; Gordon L Robertson, Food Packaging: Principles and Practice (3rd edn, crc Press 2013) 44. For detailed information about different types of additives, see Brydson (n 38) 126–157; Robertson 44–47.

54

Phthalates are used as plasticizers. Different types include Di(2-ethylhexyl) phthalate (dehp), Butyl benzyl phthalate (bbp) and Di-n-butyl phthalate (dbp).

55

US Environmental Protection Agency, T Randall Curlee and Sujit Das, Plastic Wastes: Management, Control, Recycling, and Disposal – Pollution Technology Review No. 201 (Noyes Data Corp 1991) 159; Matthias Wormuth and others, ‘What Are the Sources of Exposure to Eight Frequently Used Phthalic Acid Esters in Europeans?’ (2006) 26 Risk Analysis 803, 803.

56

See Rudolph J Jaeger and Robert J Rubin, ‘Plasticizers from Plastic Devices: Extraction, Metabolism, and Accumulation by Biological Systems’ (1970) 170 Science 460; ‘Migration of a Phthalate Ester Plasticizer from Polyvinyl Chloride Blood Bags into Stored Human Blood and Its Localization in Human Tissues’ (1972) 287 New England Journal of Medicine 1114; wh Lawrence and others, ‘A Toxicological Investigation of Some Acute, Short-Term, and Chronic Effects of Administering Di-2-Ethylhexyl Phthalate (dehp) and Other Phthalate Esters’ (1975) 9 Environmental Research 1. See also Ronald Green and others, ‘Use of Di(2-Ethylhexyl) Phthalate-Containing Medical Products and Urinary Levels of Mono(2-Ethylhexyl) Phthalate in Neonatal Intensive Care Unit Infants’ (2005) 113 Environmental Health Perspectives 1222.

57

A study found that most of the 500 plastic products sampled leached chemicals that had estrogenic activity: see Chun Z Yang and others, ‘Most Plastic Products Release Estrogenic Chemicals: A Potential Health Problem That Can Be Solved’ (2011) 119 Environmental Health Perspectives 989.

58

See Jennifer J Adibi and others, ‘Prenatal Exposures to Phthalates among Women in New York City and Krakow, Poland’ (2003) 111 Environmental Health Perspectives 1719, 1719; Ursel Heudorf, Volker Mersch-Sundermann and Jürgen Angerer, ‘Phthalates: Toxicology and Exposure’ (2007) 210 International Journal of Hygiene and Environmental Health 623, 623–64; John D Meeker, Sheela Sathyanarayana and Shanna H Swan, ‘Phthalates and Other Additives in Plastics: Human Exposure and Associated Health Outcomes’ (2009) 364 Philosophical Transactions of the Royal Society B: Biological Sciences 2097, 2098; Wormuth and others (n 55) 805.

59

See Adibi and others (n 58) 1719; ciel, ‘Plastic & Health’ (n 10) 35; Robertson (n 58) ch 22; Wormuth and others (n 55) 805–08.

60

Martin Wagner and Jörg Oehlmann, ‘Endocrine Disruptors in Bottled Mineral Water: Total Estrogenic Burden and Migration from Plastic Bottles’ (2009) 16 Environmental Science and Pollution Research 278.

61

bpa, or 2,2-bis(4-hydroxyphenyl)propane, is a high-production volume chemical which is mainly used in epoxy resins, polycarbonate plastics or polyester-styrene. It is used in impact-resistant safety equipment, baby bottles, food cans and containers, dental fillings, pipes and water storage tanks, as well as in protective coatings, adhesives and flame retardants. When bpa degrades into its monomeric form, it can leach out from the material into food and other contact materials: see Antonia M Calafat and others, ‘Exposure to Bisphenol A and Other Phenols in Neonatal Intensive Care Unit Premature Infants’ (2009) 117 Environmental Health Perspectives 639, 639; Meeker, Sathyanarayana and Swan (n 58) 2106.

62

See, in general, ciel, ‘Plastic & Health’ (n 10).

63

See Adibi and others (n 58) 1719; Gerald Ankley and others, ‘Overview of a Workshop on Screening Methods for Detecting Potential (Anti-) Estrogenic/Androgenic Chemicals in Wildlife’ (1998) 17 Environmental Toxicology and Chemistry 68, 68; Calafat and others (n 61) 639; T Colborn, FS vom Saal and AM Soto, ‘Developmental Effects of Endocrine-Disrupting Chemicals in Wildlife and Humans’. (1993) 101 Environmental Health Perspectives 378, 378; Meeker, Sathyanarayana and Swan (n 58) 2097; Robertson (n 58) 624; Wormuth and others (n 55) 803.

64

See Anderson JM Andrade and others, ‘A Dose-Response Study Following in Utero and Lactational Exposure to Di-(2-Ethylhexyl)-Phthalate (dehp): Non-Monotonic Dose-Response and Low Dose Effects on Rat Brain Aromatase Activity’ (2006) 227 Toxicology 185, 185, including references.

65

See ibid 185–86.

66

Endocrine-disrupting chemicals can be defined as ‘exogenous agents that interfere with the production, release, transport, metabolism, binding, action, or elimination of the natural hormones in the body responsible for the maintenance of homeostasis and the regulation of developmental processes’ or ‘an exogenous substance that causes adverse health effects in an intact organism, or its progeny, secondary to changes in endocrine function’: Ankley and others (n 63) 68.

67

See Laura N Vandenberg and others, ‘Hormones and Endocrine-Disrupting Chemicals: Low-Dose Effects and Nonmonotonic Dose Responses’ (2012) 33 Endocrine Reviews 378, 404.

68

See Andrade and others (n 64) 186; Ankley and others (n 63) 70; Wade V Welshons and others, ‘Large Effects from Small Exposures. I. Mechanisms for Endocrine-Disrupting Chemicals with Estrogenic Activity’. (2003) 111 Environmental Health Perspectives 994, 994; Frederick S vom Saal and Wade V Welshons, ‘Large Effects from Small Exposures. II. The Importance of Positive Controls in Low-Dose Research on Bisphenol A’ (2006) 100 Environmental Research 50; Vandenberg and others (n 67).

69

See, for instance, Adibi and others (n 58); Ankley and others (n 63); Calafat and others (n 61); Green and others (n 56); Meeker, Sathyanarayana and Swan (n 58); Jennifer David Peck and others, ‘Intra- and Inter-Individual Variability of Urinary Phthalate Metabolite Concentrations in Hmong Women of Reproductive Age’ (2009) 20 Journal of Exposure Science and Environmental Epidemiology 90; RA Rudel and others, ‘Correlations Between Urinary Phthalate Metabolites and Phthalates, Estrogenic Compounds 4-Butyl Phenol and o-Phenyl Phenol, and Some Pesticides in Home Indoor Air and House Dust’ (2008) 19 Epidemiology isee 2008 Conference Abstracts Supplement; Sheela Sathyanarayana and others, ‘Baby Care Products: Possible Sources of Infant Phthalate Exposure’ (2008) 121 Pediatrics e260; Laura N Vandenberg and others, ‘Human Exposure to Bisphenol A (BPA)’ (2007) 24 Reproductive Toxicology 139; Wormuth and others (n 55). According to a who study of 2019, leaching of additives from microplastics in freshwater and drinking water is negligible. However, if microplastics are ingested through drinking-water, the relative potential for the additives to leach from microplastics in the gastrointestinal tract is also poorly understood and needs further research: who, Microplastics in Drinking-Water (2019) ix.

70

For a critical overview on bpa-related studies, see Vandenberg and others (n 69).

71

See T Colborn and C Clement, ‘Chemically-Induced Alterations in Sexual and Functional Development: The Wildlife/Human Connection’ [1992] Advances in Modern Environmental Toxicology (USA); Colborn, vom Saal and Soto (n 63); Eun-Joo Kim, Jung-Wk Kim and Sung-Kyu Lee, ‘Inhibition of Oocyte Development in Japanese Medaka (Oryzias Latipes) Exposed to Di-2-Ethylhexyl Phthalate’ (2002) 28 Environment International 359. For an overview of tests on mammalian, fish, reptilian, amphibian, avian, and invertebrate models, see, in general, Ankley and others (n 63).

72

See Adibi and others (n 58) 1719, including references; Andrade and others (n 64) 189–90; Meeker, Sathyanarayana and Swan (n 58) 2097, including references. See also Sathyanarayana and others (n 69) e260–61; Shanna H Swan, ‘Environmental Phthalate Exposure in Relation to Reproductive Outcomes and Other Health Endpoints in Humans’ (2008) 108 Environmental Research 177.

73

See Shanna H Swan and others, ‘Decrease in Anogenital Distance among Male Infants with Prenatal Phthalate Exposure’ (2005) 113 Environmental Health Perspectives 1056, 1056. Adverse effects of phthalates and bisphenol A have also been demonstrated at environmentally relevant concentrations: see, for instance, D Andrew Crain and others, ‘An Ecological Assessment of Bisphenol-A: Evidence from Comparative Biology’ (2007) 24 Reproductive Toxicology (Elmsford, N.Y.) 225.

74

See Meeker, Sathyanarayana and Swan (n 58) 2097–98, including references.

75

See Wormuth and others (n 55) 804.

76

See Jerrold J Heindel and Frederick S vom Saal, ‘Role of Nutrition and Environmental Endocrine Disrupting Chemicals during the Perinatal Period on the Aetiology of Obesity’ (2009) 304 Molecular and Cellular Endocrinology 90, 90 and 93.

77

See Theo Colborn, ‘Neurodevelopment and Endocrine Disruption’ (2004) 112 Environmental Health Perspectives 944.

78

See Calafat and others (n 56) 639, including references.

79

See IA Lang and others, ‘Association of Urinary Bisphenol a Concentration with Medical Disorders and Laboratory Abnormalities in Adults’ (2008) 300 jama 1303, 1305–06; Meeker, Sathyanarayana and Swan (n 58) 2106; Vandenberg and others (n 69) 147.

80

See Vandenberg and others (n 67) 383.

81

See Swan (n 72) 183.

82

European Parliament and Council Regulation (ec) No 1907/2006 of 18 December 2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (reach) [2006] oj L396/1 Annex xvii.

83

See ciel, ‘Fueling Plastics: Fossils, Plastics, & Petrochemical Feedstocks’ (2017); ‘Fueling Plastics: How Fracked Gas, Cheap Oil, and Unburnable Coal Are Driving the Plastics Boom’ (2017).

84

Injection moulding and extrusion are two of the most common methods for primary shaping of plastics. The injection moulding machine consists of an injection unit (which melts the plastic and conveys it to a mould) and a clamping unit, which holds the mould in a closed position during injection (until the heated plastic has filled the mould cavity and cooled in the appropriate shape) and then opens to eject the plastic part from the mould. In the machine, the material is plasticized by heating and grinding. As soon as the molten plastic enters the cavities of the mould whose shape corresponds to the shape of the final object, it cools and solidifies. The solid plastic object is then ejected from the mould, the mould is closed and the process cycle, which lasts only a few seconds, starts again. An extruder looks similar to an injection moulding machine, but is used to produce continuous materials rather than pre-sized moulded articles. Typical products of plastic extrusion are tubes and pipes, profiles such as angles (e.g. for window frames), sheets and plates, flexible films (for bags and packaging) or wiring insulation. For more information, see Domininghaus (n 30) 243–65; Charles A Harper, Handbook of Plastic Processes (John Wiley & Sons 2006).

85

Victor Lebow, ‘Price Competition in 1955’ (1955) 31 Journal of Retailing 5, 7–8.

86

See Sterngass and Kachur (n 6) 17.

87

See ibid 19.

88

As cited in Moore and Phillips (n 3) 41.

89

Excluding synthetic fibres: see PlasticsEurope (n 4) 16. Production of rubbers and fibres amounted to 15 million tonnes and 65 million tonnes, respectively, in 2016: see Boucher and Billard (n 4). See also Geyer, Jambeck and Law (n 12).

90

unep, ‘Mapping of Global Plastics Value Chain and and Plastics Losses to the Environment (with a Particular Focus on Marine Environment)’ (2018) 24–30.

91

Diana Barrowclough, Carolyn Deere Birkbeck and Julien Christen, ‘Global Trade in Plastics: Insights from the First Life-Cycle Trade Database’ unctad Research Paper No 53 unctad/ser.rp/2020/12 1.

92

See PlasticsEurope (n 4) 24.

93

unep, ‘Mapping of Global Plastics Value Chain’ (n 90) 12.

94

If tied together, they would go around the world seven times every hour: see unep, Single-Use Plastics: A Roadmap for Sustainability (2018) 12.

95

The functions of packaging include containment, protection, utility and communication: packaging allows the transportation of liquids or granules and makes it possible to handle a number of goods in units (containment). It protects the product against contamination, damage from microorganisms or other environmental influences, impact, abrasion, corrosion etc. It might also protect humans or the environment from exposure to the product (protection). It facilitates stacking and storing of items, as well as their use (utility). Finally, packaging usually contains messages to those who interact with the products. The types of such massages range from basic consumer information, including identification of the product and its manufacturer, to bar codes (which are used to transmit price information or for tracking goods during distribution). They most often also include subtle advertisement in words, colour and shape: see Susan EM Selke, ‘Plastics in Packaging’ in AL Andrady (ed), Plastics and the Environment (Wiley Interscience 2003) 142–43.

96

See Peter Kershaw and others, ‘Plastic Debris in the Ocean’, UNEP Year Book 2011: Emerging Issues in Our Global Environment (unep 2011) 21.

97

See Selke (n 95) 144–45.

98

See Andrej Krzan and others, ‘Standardization and Certification in the Area of Environmentally Degradable Plastics’ (2006) 91 Polymer Degradation and Stability 2819, 2819; R Mohee and others, ‘Biodegradability of Biodegradable/Degradable Plastic Materials under Aerobic and Anaerobic Conditions’ (2008) 28 Waste Management 1624, 1624.

99

See Krzan and others (n 98) 2820.

100

See, in general, unep, Biodegradable Plastics & Marine Litter: Misconceptions, Concerns and Impacts on Marine Environments (n 51).

101

See Krzan and others (n 98) 2820.

102

For deteilaed information on photolysis or on thermal, mechanical or chemical degradation (including oxidation and hydrolysis), see Jort Hammer, Michiel HS Kraak and John R Parsons, ‘Plastics in the Marine Environment: The Dark Side of a Modern Gift’ in David M Whitacre (ed), Reviews of Environmental Contamination and Toxicology, vol 220 (Springer New York 2012) 11–12; Nathalie Lucas and others, ‘Polymer Biodegradation: Mechanisms and Estimation Techniques – A Review’ (2008) 73 Chemosphere 429, 431–33; Stephen P McCarthy, ‘Biodegradable Polymers’ in AL Andrady (ed), Plastics and the Environment (Wiley Interscience 2003) 313–19; Aamer Ali Shah and others, ‘Biological Degradation of Plastics: A Comprehensive Review’ (2008) 26 Biotechnology Advances 246, 249.

103

See Boyan Slat and others, How the Oceans Can Clean Themselves: A Feasibility Study (2.0, The Ocean Cleanup 2014) 411.

104

Udo Pagga, ‘Biodegradability and Compostability of Polymeric Materials in the Context of the European Packaging Regulation’ (1998) 59 Polymer Degradation and Stability 371, 372; Krzan and others (n 98) 2832. The definition corresponds to the definitions used by most standard-setting organizations in this field.

105

See McCarthy (n 102) 320; Shah and others (n 102) 251; Slat and others (n 103) 411.

106

See McCarthy (n 102) 313.

107

See Pagga (n 104) 372. The breakdown of a substance to carbon dioxide, biomass, water and other inorganic substances is often referred to as ultimate biodegradation. In contrast, ready biodegradability means the ‘biodegradability of a substance achievable in a short period of time after being exposed to the most common environment’. Inherent biodegradability refers to the ‘biodegradability of a substance achievable in the most favorable (for degradation) environment’: Krzan and others (n 98) 2832. See also iso 472:2013; oecd, ‘Revised Introduction to the OECD Guidelines for Testing of Chemicals, Section 3’, OECD Guidelines for the Testing of Chemicals, Section 3: Degradation and Accumulation (oecd Publishing 2006) 2 fn 1; J Duffus, ‘Glossary for Chemists of Terms Used in Toxicology (iupac Recommendations 1993)’ (1993) 65 Pure and Applied Chemistry 2003, 2020; Jan P Eubeler, Marco Bernhard and Thomas P Knepper, ‘Environmental Biodegradation of Synthetic Polymers ii. Biodegradation of Different Polymer Groups’ (2010) 29 TrAC Trends in Analytical Chemistry 84, 98; Lucas and others (n 102) 430; Shah and others (n 102) 250.

108

See Krzan and others (n 98) 2821; Mohee and others (n 98) 1626.

109

See R Chandra and Renu Rustgi, ‘Biodegradable Polymers’ (1998) 23 Progress in Polymer Science 1273, 1274.

110

oecd, ‘Revised Introduction to the OECD Guidelines for Testing of Chemicals, Section 3’ (n 107) 11.

111

See Ewa Rudnik, Compostable Polymer Materials (Elsevier 2008) 12–13.

112

See Pagga (n 104) 372. Compost is defined as ‘an organic soil conditioner obtained by biodegradation of a mixture consisting principally of various vegetable residues, occasionally with other organic material and having limited mineral content’: iso 472:2013, ‘Plastics – Vocabulary’.

113

See Rudnik (n 111) 13.

114

See Joseph P Greene, Sustainable Plastics: Environmental Assessments of Biobased, Biodegradable, and Recycled Plastics (John Wiley & Sons 2014) 71.

115

ibid 73.

116

See Rudnik (n 111) 13; Eddie F Gómez and Frederick C Michel, ‘Biodegradability of Conventional and Bio-Based Plastics and Natural Fiber Composites during Composting, Anaerobic Digestion and Long-Term Soil Incubation’ (2013) 98 Polymer Degradation and Stability 2583, 2584.

117

See Slat and others (n 103) 414–15.

118

See Chandra and Rustgi (n 109) 1290–91.

119

According to Shah and others, ‘[p]lastics are resistant against microbial attack, since during their short time of presence in nature evolution could not design new enzyme structures capable of degrading synthetic polymers’: Shah and others (n 102) 247. According to Gómez and Michel, most plastics are xenobiotic: ‘That is, they were not present in the environment until very recently so that the evolution of metabolic pathways necessary for their biodegradation, a process that takes millions of years, has yet to occur’: Gómez and Michel (n 116) 2584.

120

See Chandra and Rustgi (n 109) 1293; Shah and others (n 102) 250–56.

121

See Chandra and Rustgi (n 109) 1288–90; Lucas and others (n 102) 433. See also Jan P Eubeler and others, ‘Environmental Biodegradation of Synthetic Polymers I. Test Methodologies and Procedures’ (2009) 28 TrAC Trends in Analytical Chemistry 1057, 1058.

122

Chandra and Rustgi estimate ldpe with a molecular weight average of Mw = 150,000 to contain about 11,000 carbon atoms, while degradation rates are extremely slow when ‘the length of the polymer chain exceeds 24–30 carbon atoms’: Chandra and Rustgi (n 109) 1293.

123

See Lucas and others (n 102) 430. cf Shah and others (n 102) 256–57. See also Eubeler and others (n 121) 1065; Eubeler, Bernhard and Knepper (n 107) 87.

124

See Chandra and Rustgi (n 109) 1288; Hammer, Kraak and Parsons (n 102) 12; Krzan and others (n 98) 2821; Shah and others (n 102) 256.

125

See unep, Biodegradable Plastics & Marine Litter: Misconceptions, Concerns and Impacts on Marine Environments (n 51) 22. See also Gómez and Michel (n 116) 2590; Greene (n 114) 120–21; Selke (n 95) 158–59.

126

Greene (n 114) 107–13.

127

Bagasse is a fibre-pulp product from the sugarcane stalk: ibid 75.

128

See ibid 71–97; McCarthy (n 102) 361–68; Rudnik (n 111) 14–36; Shah and others (n 102) 249.

129

See Shah and others (n 102) 248; ciel, ‘Fueling Plastics: Untested Assumptions and Unanswered Questions in the Plastics Boom’ (2017) 10.

130

cf Hottle, Bilec and Landis (n 49) 1899.

131

See, for instance, Ge-Xia Wang and others, ‘Seawater-Degradable Polymers – Fighting the Marine Plastic Pollution’ (2021) 8 Advanced Science 2001121.

132

See unep, Biodegradable Plastics & Marine Litter: Misconceptions, Concerns and Impacts on Marine Environments (n 51) 3.

133

See David KA Barnes and others, ‘Accumulation and Fragmentation of Plastic Debris in Global Environments’ (2009) 364 Philosophical Transactions of the Royal Society B: Biological Sciences 1985, 390–92; Eubeler, Bernhard and Knepper (n 107) 87; Murray R Gregory and Anthony L Andrady, ‘Plastics in the Marine Environment’ in AL Andrady (ed), Plastics and the Environment (Wiley Interscience 2003) 1985–93; Hammer, Kraak and Parsons (n 102) 11; Karen K Leonas and Robert W Gorden, ‘An Accelerated Laboratory Study Evaluating the Disintegration Rates of Plastic Films in Simulated Aquatic Environments’ (1993) 1 Journal of Environmental Polymer Degradation 45.

134

See Carolyn Deere Birkbeck and others, ‘A Review of Trade Policies and Measures Relevant to Trade in Plastics and Plastic Pollution’ (2021) 16 Global Trade and Customs Journal 303, 315–17.

135

Greene (n 114) 188. See also Mohee and others (n 98) 1624; Shah and others (n 102) 250.

136

Krzan and others (n 98) 2828.

137

See astm D6400-19, ‘Standard Specification for Labeling of Plastics Designed to Be Aerobically Composted in Municipal or Industrial Facilities’ (astm International, 2019); en 13432:2000, ‘Packaging – Requirements for Packaging Recoverable through Composting and Biodegradation – Test Scheme and Evaluation Criteria for the Final Acceptance of Packaging’; iso 17088:2012, ‘Specifications for Compostable Plastics’. See also Greene (n 114) 193–204; Rudnik (n 111) 99–102. en 13432:2000 is linked to European Parliament and Council Directive 94/62/ec of 20 December 1994 on packaging and packaging waste (Packaging and Packaging Waste Directive) [1994] oj L365/10.

138

The mineralization level of cellulose is considered as the maximum mineralization achievable under the test conditions: Francesco Degli Innocenti, ‘Biodegradability and Compostability’ in Emo Chiellini and Roberto Solaro (eds), Biodegradable Polymers and Plastics (Springer Science & Business Media 2003) 39.

139

See ibid 40.

140

Greene (n 114) 188; Pagga (n 104) 372; Krzan and others (n 98) 2819. Such methods are, for instance, defined and described by oecd, ‘Revised Introduction to the OECD Guidelines for Testing of Chemicals, Section 3’ (n 107).

141

Greene (n 114) 188–89.

142

astm D7081-05, ‘Specification for Non-Floating Biodegradable Plastics in the Marine Environment (Withdrawn 2014)’ (astm International, 2005).

143

iso 22403:2020, ‘Plastics – Assessment of the Intrinsic Biodegradability of Materials Exposed to Marine Inocula under Mesophilic Aerobic Laboratory Conditions – Test Methods and Requirements’; iso 22766:2020, ‘Plastics – Determination of the Degree of Disintegration of Plastic Materials in Marine Habitats under Real Field Conditions’.

144

Jesse P Harrison and others, ‘Biodegradability Standards for Carrier Bags and Plastic Films in Aquatic Environments: A Critical Review’ 5 Royal Society Open Science 171792.

145

Greene (n 114) 72.

146

From the three isotopes of the carbon atom that can be found in nature, 14C accounts for the smallest portion. In contrast to its counterparts 12C and 13C, the 14C isotope is instable and undergoes radioactive decay. 14C concentration in living organisms and the environment is almost equal and close to constant. After decease, an organism can no longer absorb new 14C from the environment (through briefing), which is why the concentration of the 14C isotope in the death matter starts to decrease. The concentration of 14C in a (non-living) material halves in 5,700 years. In 50,000 years, proportions are too small to be measured. For this reason, 14C concentrations in fossil resources are close to zero. The measuring of the radioactivity of 14C in plastic materials therefore allows the determination of organic content from renewable resources, as 14C concentrations in fossil resources are negligible.

147

E.g. astm D6866-18, ‘Test Methods for Determining the Biobased Content of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis’ (2018). See Greene (n 114) 72.

148

For more information, see Petra Horvat and Andrej Kržan, ‘Certification of Bioplastics’ (Innovative Value Chain Development for Sustainable Plastics in Central Europe (PLASTiCE) 2012).

149

See Paul T Williams, Waste Treatment and Disposal (2nd edn, John Wiley & Sons 2005) 49–51.

150

Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal (1989 Basel Convention) (adopted on 22 March 1989, entered into force on 5 May 1992) 1673 unts 126, 28 ilm 657 (1989) art 2.1. A very similar definition of waste is contained in European Parliament and Council Directive 2008/98/ec of 19 November 2008 on Waste and Repealing Certain Directives (Waste Framework Directive) [2008] oj L312/3, as well as in iso 14040:2006, ‘Environmental Management – Life Cycle Assessment – Principles and Framework’.

151

See Jagdeep Singh and others, ‘Progress and Challenges to the Global Waste Management System’ (2014) 32 Waste Management & Research 800, 800.

152

See Daniel Hoornweg and Perinaz Bhada-Tata, ‘What a Waste: A Global Review of Solid Waste Management’ (World Bank 2012) No. 15 7; Lemann (n 45) 32; Anne Scheinberg, David C Wilson and Ljiljana Rodic, Solid Waste Management in the World’s Cities: Water and Sanitation in the World’s Cities 2010 (Earthscan for UN-habitat 2010) 6–7.

153

See Scheinberg, Wilson and Rodic (n 147) 7.

154

Hoornweg and Bhada-Tata (n 152) 3.

155

G Bylinsky, ‘Manufacturing for Reuse’ (1995) 131 Fortune 102; Singh and others (n 151) 800.

156

See Lebow (n 85) 7–8. Shortly after Lebow’s call for a ‘constantly more expensive consumption’, on 1st August 1955, an article published in life, one of the United States’ leading magazines, celebrated the new, modern, throw-away lifestyle, which was supposed to liberate housewives from arduous housekeeping tasks: ‘Throwaway Living: Disposable Items Cut Down Household Chores’ [1955] life 49. The cover picture shows a happy family in the middle of numerous flying disposable objects, which do not have to be cleaned after use any longer but can now easily be discarded.

157

Studies suggest that plastic products can take up to thousands of years to decompose in the natural environment: see unep, Single-Use Plastics: A Roadmap for Sustainability (n 94) 12.

158

See, in general, Tim Cooper and C Kieren Mayers, Prospects for Household Appliances (Urban Mines 2000); Tim Cooper, ‘Slower Consumption Reflections on Product Life Spans and the “Throwaway Society”’ (2005) 9 Journal of Industrial Ecology 51; Michel Kostecki (ed), The Durable Use of Consumer Products: New Options for Business and Consumption (Springer US 1998); John J Heim, ‘Consumer Demand for Durable Goods, Nondurable Goods and Services’ (2009) 2 Proceedings of the New York State Economics Association 22.

159

unep, Addressing Single-Use Plastic Products Pollution Using a Life Cycle Approach (2021) 5.

160

See, in general, Vance Packard, The Waste Makers (Reprint edn, Ig Publishing 1960); Peter L Swan, ‘Optimum Durability, Second-Hand Markets, and Planned Obsolescence’ (1972) 80 Journal of Political Economy 575; Jeremy Bulow, ‘An Economic Theory of Planned Obsolescence’ (1986) 101 The Quarterly Journal of Economics 729; Michael Waldman, ‘A New Perspective on Planned Obsolescence’ (1993) 108 The Quarterly Journal of Economics 273; Atsuo Utaka, ‘Planned Obsolescence and Marketing Strategy’ (2000) 21 Managerial and Decision Economics 339; Giles Slade, Made to Break: Technology and Obsolescence in America (Harvard University Press 2007); Joseph Guiltinan, ‘Creative Destruction and Destructive Creations: Environmental Ethics and Planned Obsolescence’ (2008) 89 Journal of Business Ethics 19.

161

Thorstein Veblen, ‘The Theory of the Leisure Class’ [1899] New York: The New American Library. See also Laurie Simon Bagwell and B Douglas Bernheim, ‘Veblen Effects in a Theory of Conspicuous Consumption’ (1996) 86 The American Economic Review 349; Aron O’Cass and Hmily McEwen, ‘Exploring Consumer Status and Conspicuous Consumption’ (2004) 4 Journal of Consumer Behaviour 25; Andrew B Trigg, ‘Veblen, Bourdieu, and Conspicuous Consumption’ (2001) 35 Journal of Economic Issues 99.

162

See, for instance, Richard C Barnett, Joydeep Bhattacharya and Helle Bunzel, ‘Choosing to Keep Up with the Joneses and Income Inequality’ (2009) 45 Economic Theory 469; Markus Christen and Ruskin M Morgan, ‘Keeping Up With the Joneses: Analyzing the Effect of Income Inequality on Consumer Borrowing’ (2005) 3 Quantitative Marketing and Economics 145; Jordi Galí, ‘Keeping up with the Joneses: Consumption Externalities, Portfolio Choice, and Asset Prices’ (1994) 26 Journal of Money, Credit and Banking 1; Michael Rauscher, ‘Keeping up with the Joneses: Chaotic Patterns in a Status Game’ (1992) 40 Economics Letters 287.

163

See Daniel Kahneman and others, ‘Would You Be Happier If You Were Richer? A Focusing Illusion’ (2006) 312 Science 1908; John Knight and Ramani Gunatilaka, ‘Income, Aspirations and the Hedonic Treadmill in a Poor Society’ (2012) 82 Journal of Economic Behavior & Organization 67; Sonja Lyubomirsky, ‘Hedonic Adaptation to Positive and Negative Experiences’ in Susan Folkman (ed), The Oxford Handbook of Stress, Health, and Coping (Oxford University Press, USA 2010); Alois Stutzer, ‘The Role of Income Aspirations in Individual Happiness’ (2004) 54 Journal of Economic Behavior & Organization 89.

164

See Hélène Cherrier and Tresa Ponnor, ‘A Study of Hoarding Behavior and Attachment to Material Possessions’ (2010) 13 Qualitative Market Research: An International Journal 8; Ashley E Nordsletten and David Mataix-Cols, ‘Hoarding versus Collecting: Where Does Pathology Diverge from Play?’ (2012) 32 Clinical Psychology Review 165.

165

See Samuel Alexander, ‘Planned Economic Contraction: The Emerging Case for Degrowth’ (2012) 21 Environmental Politics 349; Giorgos Kallis, Christian Kerschner and Joan Martinez-Alier, ‘The Economics of Degrowth’ (2012) 84 Ecological Economics 172; Giorgos Kallis, ‘In Defence of Degrowth’ (2011) 70 Ecological Economics 873; Christian Kerschner, ‘Economic De-Growth vs. Steady-State Economy’ (2010) 18 Journal of Cleaner Production 544; Serge Latouche, Le pari de la décroissance (Fayard 2006); Vers une société d’abondance frugale: Contresens et controverses de la décroissance (Fayard/Mille et une nuits 2011); Joan Martínez-Alier and others, ‘Sustainable De-Growth: Mapping the Context, Criticisms and Future Prospects of an Emergent Paradigm’ (2010) 69 Ecological Economics 1741; Joan Martínez-Alier, ‘Environmental Justice and Economic Degrowth: An Alliance between Two Movements’ (2012) 23 Capitalism Nature Socialism 51; François Schneider, Giorgos Kallis and Joan Martinez-Alier, ‘Crisis or Opportunity? Economic Degrowth for Social Equity and Ecological Sustainability’ (2010) 18 Journal of Cleaner Production 511; Peter A Victor, ‘Growth, Degrowth and Climate Change: A Scenario Analysis’ (2012) 84 Ecological Economics 206.

166

See William Young and others, ‘Sustainable Consumption: Green Consumer Behaviour When Purchasing Products’ (2010) 18 Sustainable Development 20. See also Andrew Gilg, Stewart Barr and Nicholas Ford, ‘Green Consumption or Sustainable Lifestyles? Identifying the Sustainable Consumer’ (2005) 37 Futures 481; Stephanie D Preston, ‘Toward an Interdisciplinary Science of Consumption’ (2011) 1236 Annals of the New York Academy of Sciences 1; Gill Seyfang, The New Economics of Sustainable Consumption: Seeds of Change (1st edn, Palgrave Macmillan 2009); Gert Spaargaren, ‘Sustainable Consumption: A Theoretical and Environmental Policy Perspective’ (2003) 16 Society & Natural Resources 687.

167

National waste generation rates fluctuate from 0.11 to 4.54 kg per capita per day: Slipa Kaza and others, What a Waste 2.0: A Global Snapshot of Solid Waste Management to 2050 (World Bank Group 2018) 18.

168

See Hoornweg and Bhada-Tata (n 152) 1; Azni Idris, Bulent Inanc and Mohd Nassir Hassan, ‘Overview of Waste Disposal and Landfills/Dumps in Asian Countries’ (2004) 6 Journal of Material Cycles and Waste Management 104, 104.

169

See unep, Single-Use Plastics: A Roadmap for Sustainability (n 94) 5. On per capita plastic waste generation rates, see also grid-Arendal, ‘The Trade in Plastic Waste’ (April 2017) <https://grid-arendal.maps.arcgis.com/apps/Cascade/index.html?appid=002738ffb18548818a61cc88161ac464> accessed 19 February 2022.

170

Accurate data of waste arisings are difficult to collect and compare due to divergent definitions, inconsistent categorization and different collection, quantification and reporting methods. Data is, moreover, often incomplete and does not capture system losses. Waste-reduction strategies thus generally include as a key element the availability of accurate and comparable data on waste generation and composition: see Williams (n 149) 64. For detailed data on waste generation in the United States, see US Environmental Protection Agency, Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Tables and Figures for 2012 (2014). For data on waste generation in oecd countries, see oecd, ‘Municipal Waste (Indicator)’ (2022) <https://data.oecd.org/waste/municipal-waste.htm> accessed 19 February 2022.

171

See European Environment Agency, ‘Total Waste Generation by Sector, 2004’ (2009) <http://www.eea.europa.eu/data-and-maps/figures/total-waste-generation-by-sector-2004> accessed 19 February 2022; Eurostat, ‘Archive: Waste Statistics’ (Statistics Explained, 2011) <http://ec.europa.eu/eurostat/statistics-explained/index.php/Archive:Waste_statistics> accessed 19 February 2022; oecd, ‘Generation of Primary Waste by Sector’ (2018) <https://stats.oecd.org/Index.aspx?DataSetCode=WSECTOR> accessed 19 February 2022.

172

According to estimations of the World Bank, average daily per capita generation of industrial waste is at 12.73 kg, more than 17 times higher than for municipal solid waste: Kaza and others (n 167) 36. See also Singh and others (n 151) 801–02.

173

See Williams (n 149) 68.

174

Hoornweg and Bhada-Tata (n 152) 17; Idris, Inanc and Hassan (n 168) 104; Kaza and others (n 167) 29 ff.

175

See Selke (n 95) 140–41.

176

See Hoornweg and Bhada-Tata (n 152) 16. About 21 per cent of an estimated amount of worldwide 20–50 million tonnes of wastes from electrical or electronic equipment are plastics. This corresponded in 2012 to a maximum of about 10.5 million tonnes – tendency increasing: Jef R Peeters and others, ‘Closed Loop Recycling of Plastics Containing Flame Retardants’ (2014) 84 Resources, Conservation and Recycling 35, 35.

177

Kaza and others (n 167) 4–6.

178

Geyer, Jambeck and Law (n 12); unep, Single-Use Plastics: A Roadmap for Sustainability (n 94) 5.

179

Material recovery is referred to as primary recycling (if the end product has characteristics similar to the ones of the original product) or secondary recycling (if the end product has characteristics different from those of the original product). For more information about the process, see Michael M Fisher, ‘Plastics Recycling’ in AL Andrady (ed), Plastics and the Environment (Wiley Interscience 2003) 583–617; Greene (n 114) 114–17.

180

Fisher (n 179) 565.

181

Scheinberg, Wilson and Rodic (n 152) 126.

182

Hoornweg and Bhada-Tata (n 152) 5; Scheinberg, Wilson and Rodic (n 152) 128. See also Karin Blumenthal, ‘Generation and Treatment of Municipal Waste’ (Eurostats 2011) 31/2011 passim; Fisher (n 179) 569–73; ‘Waste Atlas – Interactive Map with Visualized Waste Management Data’ <http://www.atlas.d-waste.com> accessed 19 February 2022.

183

For instance, chemical recycling of waste polymers into carbon nanomaterials has been referred to as upcycling: Vilas Ganpat Pol, ‘Upcycling: Converting Waste Plastics into Paramagnetic, Conducting, Solid, Pure Carbon Microspheres’ (2010) 44 Environmental Science & Technology 4753; Chuanwei Zhuo and Yiannis A Levendis, ‘Upcycling Waste Plastics into Carbon Nanomaterials: A Review’ (2014) 131 Journal of Applied Polymer Science 39931 (1). The production of biogas from wastes has also been associated with upcycling: Michael Martin and Amin Parsapour, ‘Upcycling Wastes with Biogas Production: An Exergy and Economic Analysis’, Venice 2012: International Symposium on Energy from Biomass and Waste (2012).

184

Fisher (n 179) 581.

185

Domininghaus (n 30) 2.

186

Ashwani K Gupta and David G Lilley, ‘Thermal Destruction of Wastes and Plastics’ in AL Andrady (ed), Plastics and the Environment (Wiley Interscience 2003) 635.

187

José Aguado and David P Serrano, Feedstock Recycling of Plastic Wastes (Royal Society of Chemistry 1999) 20.

188

See Scheinberg, Wilson and Rodic (n 152) xx.

189

Hoornweg and Bhada-Tata (n 152) 1.

190

ibid 14.

191

‘Waste Atlas – Interactive Map with Visualized Waste Management Data’ (n 182).

192

See, in general, Singh and others (n 151).

193

Thaddeus Chidi Nzeadibe and Ignatius Ani Madu, ‘Open Dump’ in Carl Zimring and William Rathje, Encyclopedia of Consumption and Waste: The Social Science of Garbage (sage Publications, Inc 2012) 632.

194

Scheinberg, Wilson and Rodic (n 152) 16.

195

Philip Rushbrook, Solid Waste Landfills in Middle- and Lower-Income Countries: A Technical Guide to Planning, Design, and Operation (The World Bank 1999) 12. See also Hoornweg and Bhada-Tata (n 152) 6 and 26.

196

Rushbrook (n 195) 16.

197

Nzeadibe and Madu (n 193) 632. For a list of impacts of open dumping sites on human health and the environment, see also International Solid Waste Association iswa, ‘Closing of Open Dumps: Key Issue Paper’ (2007) 2–4.

198

Hoornweg and Bhada-Tata (n 152) 26.

199

Scheinberg, Wilson and Rodic (n 152) 15.

200

ibid.

201

ciel, ‘Plastic & Health’ (n 10) 43, with reference; International Solid Waste Association iswa (n 197) 3; Abhijit Roy, ‘Open Burning’ in Carl Zimring and William Rathje, Encyclopedia of Consumption and Waste: The Social Science of Garbage (sage Publications, Inc 2012) 629–30.

202

European Commission, Proposal for a Council Directive on the Landfill of Waste 1997 [com (97) 105 final [1997] oj C156/10], as cited in Williams (n 149) 174.

203

Michiel RJ Doorn, Morton A Barlaz and Susan A Thorneloe, Estimate of Global Methane Emissions from Landfills and Open Dumps (US Environmental Protection Agency epa 1995) 1.

204

ipcc, ‘Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change’ (Cambridge University Press 2013) 714. Greenhouse gases are gases which, when in the atmosphere, allow transmission of short-wave radiation from the sun, but withhold long-wave radiation reflected from the Earth’s surface, which causes global warming: Williams (n 149) 174 and 215. The global warming potential is the ratio of change in global mean surface temperature at a chosen point in time from the substance of interest relative to that from CO2: see ipcc 663.

205

International Solid Waste Association iswa (n 197) 3.

206

Gómez and Michel (n 116) 2589.

207

Aguado and Serrano (n 187) 15.

208

See Idris, Inanc and Hassan (n 168) 105.

209

Heike Weber, ‘Landfills, Modern’ in Carl Zimring and William Rathje, Encyclopedia of Consumption and Waste: The Social Science of Garbage (sage Publications, Inc 2012) 473.

210

Aguado and Serrano (n 187) 15.

211

Hoornweg and Bhada-Tata (n 152) 4; Idris, Inanc and Hassan (n 168) 104.

212

Aguado and Serrano (n 187) 15.

213

Weber (n 209) 471.

214

Shah and others (n 102) 248.

215

Hoornweg and Bhada-Tata (n 152) 4. For detailed information about quantities and impacts of different incineration emissions, see Williams (n 149) 263–304.

216

Gupta and Lilley (n 186) 630.

217

mpm Taha and others, ‘Bioaerosol Releases from Compost Facilities: Evaluating Passive and Active Source Terms at a Green Waste Facility for Improved Risk Assessments’ (2006) 40 Atmospheric Environment 1159, 1159.

218

See, in general, Peter Sykes, Ken Jones and JohnD Wildsmith, ‘Managing the Potential Public Health Risks from Bioaerosol Liberation at Commercial Composting Sites in the UK: An Analysis of the Evidence Base’ (2007) 52 Resources, Conservation and Recycling 410; Taha and others (n 217).

219

Greene (n 114) 133, including references.

220

Hoornweg and Bhada-Tata (n 152) 1; Kaza and others (n 167) 102.

221

See, in general, Kaveri Gill, Of Poverty and Plastic: Scavenging and Scrap Trading Entrepreneurs in India’s Urban Informal Economy (Paperback edn, Oxford University Press 2012). See also Scheinberg, Wilson and Rodic (n 152) 1–2; Hoornweg and Bhada-Tata (n 152) 15.

222

Hoornweg and Bhada-Tata (n 152) 28; Roland Linzner and Stefan Salhofer, ‘Municipal Solid Waste Recycling and the Significance of Informal Sector in Urban China’ (2014) 32 Waste Management & Research 896, 905.

223

See wto Notification g/tbt/n/chn/1211 of 18 July 2017; wto Notification g/tbt/n/chn/1228 of 15 November 2017. See also Amy L Brooks, Shunli Wang and Jenna R Jambeck, ‘The Chinese Import Ban and Its Impact on Global Plastic Waste Trade’ (2018) 4 Science Advances eaat0131.

224

wto Committee on Trade and Environment, ‘Communication on Trade in Plastics, Sustainability and Development by the United Nations Conference on Trade and Development (UNCTAD)’ (2020) job/te/63 5–6.

225

Other relevant factors for material selection include feedstock and processing costs, processability, service performance of the material with regard to the object’s final purpose, market conditions, legal requirements, available technologies and consumer preferences.

226

Yates and Barlow (n 50) 55. See also Domininghaus (n 30) 2.

227

Shawn Hunter, Richard Helling and Dawn Shiang, ‘Integration of LCA and Life-Cycle Thinking within the Themes of Sustainable Chemistry & Engineering’ in Mary Ann Curran (ed), Life Cycle Assessment Handbook: A Guide for Environmentally Sustainable Products (John Wiley & Sons 2012) 369–73.

228

See Jeroen B Guinée and others, Handbook on Life Cycle Assessment: Operational Guide to the ISO Standards, vol 7 (Jeroen B Guinée ed, Kluwer Academic Publishers 2004) 6; iso 14040:2006 (n 150).

229

While product footprints usually are subject to bottom-up lca, environmentally extended input–output analysis (eeioa) is used to assess footprints at global or national level: see Julien Boucher and others, Review of Plastic Footprint Methodologies: Laying the Foundation for the Development of a Standardised Plastic Footprint Measurement Tool (iucn 2019) 7. Further tools or techniques include, for instance, risk assessment, environmental performance evaluation, environmental auditing and environmental impact assessment. See Guinée and others (n 228) 9; Mary Ann Curran, ‘Life Cycle Assessment: A Review of the Methodology and Its Application to Sustainability’ (2013) 2 Current Opinion in Chemical Engineering 273, 275–76.

230

Gjalt Huppes and Mary Ann Curran, ‘Environmental Life Cycle Assessment: Background and Perspective’ in Mary Ann Curran (ed), Life Cycle Assessment Handbook: A Guide for Environmentally Sustainable Products (John Wiley & Sons 2012) 1–4.

231

iso 14040:2006 (n 150). See also Guinée and others (n 228) 5.

232

Guinée and others (n 228) 5.

233

iso 14040:2006 (n 150).

234

See, for instance, Thomas Koellner and Roland Scholz, ‘Assessment of Land Use Impacts on the Natural Environment. Part 1: An Analytical Framework for Pure Land Occupation and Land Use Change’ (2007) 12 The International Journal of Life Cycle Assessment 16, 16.

235

iso 14040:2006 (n 150).

236

See Yates and Barlow (n 50) 55.

237

Guinée and others (n 228) 6. The availability of reliable data is one of the biggest challenges related to lcas. Databases in increasingly standardized formats are being developed in different countries. See ibid 8.

238

Michaelangelo D Tabone and others, ‘Sustainability Metrics: Life Cycle Assessment and Green Design in Polymers’ (2010) 44 Environmental Science & Technology 8264, 8264.

239

See James Fava and others (eds), Conceptual Framework for Life-Cycle Impact Assessment (setac 1993); as cited in Evan Stuart Andrews and others, Guidelines for Social Life Cycle Assessment of Products: Social and Socio-Economic LCA Guidelines Complementing Environmental LCA and Life Cycle Costing, Contributing to the Full Assessment of Goods and Services within the Context of Sustainable Development (Catherine Benoît and Bernard Mazijn eds, unep 2009) 17.

240

Global Ministerial Environment Forum, ‘Malmö Ministerial Declaration’ (Sixth Special Session of the unep Governing Council 2000) unep/gc/dec/ss.vi/1.

241

UN Conference on Sustainable Development, ‘A 10-Year Framework of Programmes on Sustainable Consumption and Production Patterns’ (2012) a/conf.216/5.

242

Andrews and others (n 239) 5.

243

ibid 35.

244

See David Hunkeler and others (eds), Environmental Life Cycle Costing (setac; crc Press 2008) 173. Life-cycle costing was developed by the US military in the 1960s and is broadly used in different industry sectors, especially for investment goods: see Andrews and others (n 239) 35; Huppes and Curran (n 230) 1.

245

On the concept of sustainable development in international law, see Section 2.1.A.ii.2 below.

246

Andreas Ciroth and others, Towards a Life Cycle Sustainablity Assessment: Making Informed Choices on Products (Sonia Valdivia and others eds, unep/setac Life Cycle Initiative 2011) 1.

247

Boucher and others (n 229) 7.

248

Hottle, Bilec and Landis (n 49) 1901–02; Tabone and others (n 238) 8266; Yates and Barlow (n 50) 55.

249

Yates and Barlow (n 50) 62.

250

See Hottle, Bilec and Landis (n 49) 1901.

251

Yates and Barlow (n 50) 55.

252

Hottle, Bilec and Landis (n 49) 1898.

253

Yates and Barlow (n 50) 55.

254

A kilogram of plastic produces an average of 2.8 kg of carbon dioxide: Hottle, Bilec and Landis (n 49) 1899.

255

Tarja Häkkinen and Sirje Vares, ‘Environmental Impacts of Disposable Cups with Special Focus on the Effect of Material Choices and End of Life’ (2010) 18 Journal of Cleaner Production 1458, 1462.

256

Gómez and Michel (n 116) 2584.

257

Yates and Barlow (n 50) 55. A complete replacement of polyolefins by bio-based plastics in packaging could cause serious competition between polymer feedstock and food production: see Gerald Scott, ‘Science and Standards’ in Emo Chiellini and Roberto Solaro (eds), Biodegradable Polymers and Plastics (Springer Science & Business Media 2003) 5.

258

Gómez and Michel (n 116) 2584.

259

See Hottle, Bilec and Landis (n 49) 1901.

260

Gómez and Michel (n 116) 2590.

261

ibid 2584.

262

Yates and Barlow (n 50) 62.

263

Hottle, Bilec and Landis (n 49) 1905.

264

ibid 1905. See also Yates and Barlow (n 50) 62.

265

Gómez and Michel (n 116) 2584.

266

ibid.

267

The assessment on green design was based on the Twelve Principles of Green Chemistry as developed by Paul Anastas and John Warner (Prevention; Atom Economy; Less Hazardous Chemical Syntheses; Designing Safer Chemicals; Safer Solvents and Auxiliaries; Design for Energy Efficiency; Use of Renewable Feedstocks; Reduce Derivatives; Catalysis; Design for Degradation; Real-time analysis for Pollution Prevention; Inherently Safer Chemistry for Accident Prevention) and the Twelve Principles of Green Engineering as developed by Paul Anastas and Julie Zimmerman (Inherent Rather Than Circumstantial; Prevention Instead of Treatment; Design for Separation; Maximize Efficiency; Output-Pulled Versus Input-Pushed; Conserve Complexity; Durability Rather Than Immortality; Meet Need, Minimize Excess; Minimize Material Diversity; Integrate Material and Energy Flows; Design for Commercial “Afterlife”; Renewable Rather Than Depleting): Tabone and others (n 238) 8265. See also Paul T Anastas and JC Warner, Green Chemistry: Theory and Practice (Oxford University Press 1998); Paul T Anastas and Julie B Zimmerman, ‘Design through the 12 Principles of Green Engineering’ (2003) 37 Environmental Science & Technology 94A.

268

Tabone and others (n 238) 8264.

269

See, for instance, Yates and Barlow (n 50) 65.

270

Aaron Dormer and others, ‘Carbon Footprint Analysis in Plastics Manufacturing’ (2013) 51 Journal of Cleaner Production 133, 133. Up to 90 per cent of the energy used in the production of plastics from virgin materials can be saved if plastics are recycled instead. One tonne of recycled plastic saves 5,774 kWh of energy, 16.3 barrels of oil and 22 cubic metres of landfill. See bir, ‘BIR – Bureau of International Recycling: Plastics’ <https://archive.bir.org/industry/plastics/> accessed 19 February 2022.

271

Greene (n 114) 120.

272

Hottle, Bilec and Landis (n 49) 1905.

273

JH Song and others, ‘Biodegradable and Compostable Alternatives to Conventional Plastics’ (2009) 364 Philosophical Transactions of the Royal Society B: Biological Sciences 2127, 2130.

274

Disposable pet cups were, for instance, reported to have greater use of resources and release of harmful emissions than pe- or PLA-coated carton-based cups: Häkkinen and Vares (n 255) 1461. By contrast, plastic baby food pots were found to impose a slightly smaller burden to the environment than glass jars in three European countries: Sebastien Humbert and others, ‘Life Cycle Assessment of Two Baby Food Packaging Alternatives: Glass Jars vs. Plastic Pots’ (2009) 14 The International Journal of Life Cycle Assessment 95. In an assessment of different sorts of shopping bags in China, Hong Kong and India, bags made from non-woven fabrics, especially pp, showed the least global warming potential, followed by woven cotton bags. When compared to these two groups, both plastic and paper bags were found to have high global warming potential, especially because reuse rates are considerably lower for plastic and paper bags than for non-woven and woven bags: Subramanian Senthilkannan Muthu and others, ‘Carbon Footprint of Shopping (Grocery) Bags in China, Hong Kong and India’ (2011) 45 Atmospheric Environment 469, 472.

275

A report published by iucn found that there is still no robust impact assessment method in place to allow full alignment of plastic leakage approaches with the lca framework: Boucher and others (n 229) 35.

276

unep, Addressing Single-Use Plastic Products Pollution Using a Life Cycle Approach (n 159).

277

Gregory and Andrady (n 133) 379.

278

Earle (n 14) 17–18.

279

A study on anthropogenic impact on different marine ecosystems concluded in 2008 that ‘no area is unaffected by human influence and that a large fraction (41 per cent) is strongly affected by multiple drivers’: Benjamin S Halpern and others, ‘A Global Map of Human Impact on Marine Ecosystems’ (2008) 319 Science 948, 948.

280

See United Nations, ‘UNCLOS at 30’ (United Nations 2012) 6 <http://www.un.org/depts/los/convention_agreements/pamphlet_unclos_at_30.pdf> accessed 19 February 2022; Tullio Treves, ‘Principles and Objectives of the Legal Regime Governing Areas Beyond National Jurisdiction’ in AG Oude Elferink and EJ Molenaar (eds), The International Legal Regime of Areas beyond National Jurisdiction: Current and Future Developments (Koninklijke Brill NV 2010) 22.

281

Other factors include overfishing, the widespread use of destructive fishing techniques and the destruction of habitats, the continuous loss of biological diversity, ocean acidification due to global warming, eutrophication and noise pollution, as well as pollution due to the release of oil and other persistent pollutants into the sea or nuclear testing.

282

See Gregory and Andrady (n 133) 380.

283

United Nations, ‘Glossary of Environment Statistics’ (United Nations 1997) Series F, No. 67 (UN Doc. st/esa/stat/ser.f/67) 47; gesamp, ‘The State of the Marine Environment’ (unep 1990) Reports and Studies No 39, preliminary notes. cf United Nations Convention on the Law of the Sea (unclos) (opened for signature on 10 December 1982, entered into force on 16 November 1994) 1833 unts 397, 21 ilm 1261 (1982) art 1(4).

284

unep, Marine Litter: A Global Challenge (unep 2009) 13. See also Gregory and Andrady (n 133) 379.

285

unep, Marine Litter (n 284) 13.

286

Hammer, Kraak and Parsons (n 102) 2.

287

See David KA Barnes, ‘Remote Islands Reveal Rapid Rise of Southern Hemisphere Sea Debris’ (2005) 5 Scientific World Journal 915, 918; Barnes and others (n 133) 1987; José GB Derraik, ‘The Pollution of the Marine Environment by Plastic Debris: A Review’ (2002) 44 Marine Pollution Bulletin 842, 843; Gregory and Andrady (n 133) 380; MR Gregory and PG Ryan, ‘Pelagic Plastics and Other Seaborne Persistent Synthetic Debris: A Review of Southern Hemisphere Perspectives’ in James M Coe and Donald B Rogers (eds), Marine Debris: Sources, Impacts and Solutions (Springer New York 1997) 63; Carey Morishige and others, ‘Factors Affecting Marine Debris Deposition at French Frigate Shoals, Northwestern Hawaiian Islands Marine National Monument, 1990–2006’ (2007) 54 Marine Pollution Bulletin 1162, 1167; Slat and others (n 103) 38.

288

First indications of plastic debris accumulation in the marine environment were provided in the 1960s, when plastic fragments and pellets were discovered in the guts of dead sea birds: see Karl W Kenyon and Eugene Kridler, ‘Laysan Albatrosses Swallow Indigestible Matter’ (1969) 86 Auk 339, 340–41; Barnes and others (n 133) 1988 and 1993. First direct records of plastic fragments in open seawater and other marine environments date from the 1970s: see JB Buchanan, ‘Pollution by Synthetic Fibres’ (1971) 2 Marine Pollution Bulletin 23; Edward J Carpenter and others, ‘Polystyrene Spherules in Coastal Waters’ (1972) 178 Science 749; EJ Carpenter and KL Smith, ‘Plastics on the Sargasso Sea Surface’ (1972) 175 Science 1240; JB Colton, BR Burns and FD Knapp, ‘Plastic Particles in Surface Waters of the Northwestern Atlantic’ (1974) 185 Science 491; H Hays and G Cormons, ‘Plastic Particles Found in Tern Pellets, on Coastal Beaches and at Factory Sites’ (1974) 5 Marine Pollution Bulletin 44; S Kartar, F Abou-Seedou and M Sainsbury, ‘Polystyrene Spherules in the Severn Estuary – A Progress Report’ (1976) 7 Marine Pollution Bulletin 52; S Kartar, RA Milne and M Sainsbury, ‘Polystyrene Waste in the Severn Estuary’ (1973) 4 Marine Pollution Bulletin 144; AW Morris and EI Hamilton, ‘Polystyrene Spherules in the Bristol Channel’ (1974) 5 Marine Pollution Bulletin 26. In the subsequent decades, there was a substantial increase in anthropogenic debris in the seas: see Barnes (n 287); Barnes and others (n 133) 1988; Derraik (n 287); Trevor R Dixon and TJ Dixon, ‘Marine Litter Surveillance’ (1981) 12 Marine Pollution Bulletin 289.

289

Barnes and others (n 133) 1985; unep, Marine Litter: An Analytical Overview (unep 2005) 1.

290

Richard C Thompson, ‘Plastic Debris in the Marine Environment: Consequences and Solutions’ in Jochen C Krause, Henning von Nordheim and Stefan Bräger (eds), Marine Nature Conservation in Europe 2006: Proceedings of the Symposium held in Stralsund, Germany, 8th–12th May 2006 (German Federal Agency for Nature Conservation 2007) 108.

291

See Boucher and others (n 229) 3; Jenna R Jambeck and others, ‘Plastic Waste Inputs from Land into the Ocean’ (2015) 347 Science 768, 768.

292

Gregory and Andrady (n 133) 384; Hammer, Kraak and Parsons (n 102) 13; unep, Marine Litter: An Analytical Overview (n 289) ii; unep, UNEP Year Book 2014: Emerging Issues in Our Global Environment (unep 2014) 49.

293

See Barnes and others (n 133) 1989 and 1995; CJ Moore and others, ‘A Comparison of Plastic and Plankton in the North Pacific Central Gyre’ (2001) 42 Marine Pollution Bulletin 1297, 1299; Kershaw and others (n 96) 22.

294

Hammer, Kraak and Parsons (n 102) 5; L Lebreton and others, ‘Evidence That the Great Pacific Garbage Patch Is Rapidly Accumulating Plastic’ (2018) 8 Scientific Reports 12 <http://www.nature.com/articles/s41598-018-22939-w> accessed 19 February 2022.

295

Barnes and others (n 133) 1988; Hammer, Kraak and Parsons (n 102) 13. Plastic fragments may also sink if their density changes due to the leaching of additives: Francois Galgani, Georg Hanke and Thomas Maes, ‘Global Distribution, Composition and Abundance of Marine Litter’ in Melanie Bergmann, Lars Gutow and Michael Klages (eds), Marine Anthropogenic Litter (Springer 2015) 36.

296

Richard C Thompson, ‘Microplastics in the Marine Environment: Sources, Consequences and Solutions’ in Melanie Bergmann, Lars Gutow and Michael Klages (eds), Marine Anthropogenic Litter (Springer 2015) 192. From all plastic debris at the sea, it is estimated that about 15 per cent is floating on the surface, 15 per cent is washed ashore and 70 per cent eventually sinks to the sea bottom: see Hammer, Kraak and Parsons (n 102) 13; unep, Marine Litter – Trash That Kills (2001) 4.

297

Marcus Eriksen and others, ‘Plastic Pollution in the World’s Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea’ (2014) 9 PLoS ONE e111913, 7. cf Andrés Cózar and others, ‘Plastic Debris in the Open Ocean’ (2014) 111 Proceedings of the National Academy of Sciences 10239.

298

Lebreton and others (n 294).

299

See Eriksen and others (n 297) 10; Lebreton and others (n 294) 12; AE Schwarz and others, ‘Sources, Transport, and Accumulation of Different Types of Plastic Litter in Aquatic Environments: A Review Study’ (2019) 143 Marine Pollution Bulletin 92; Erik van Sebille and others, ‘A Global Inventory of Small Floating Plastic Debris’ (2015) 10 Environmental Research Letters 124006; Alexandra ter Halle and others, ‘Understanding the Fragmentation Pattern of Marine Plastic Debris’ (2016) 50 Environmental Science & Technology 5668.

300

In the past, oceanographers repeatedly tracked flotsam, including some of the spilled cargo from thousands of containers that annually fall overboard, to better understand global patterns of oceanic currents: see Curtis C Ebbesmeyer and Ingraham W James, ‘Shoe Spill in the North Pacific’ (1992) 73 Eos, Transactions American Geophysical Union 361; ‘Pacific Toy Spill Fuels Ocean Current Pathways Research’ (1994) 75 Eos, Transactions American Geophysical Union 425.

301

See Robert H Day and David G Shaw, ‘Patterns in the Abundance of Pelagic Plastic and Tar in the North Pacific Ocean, 1976–1985’ (1987) 18 Marine Pollution Bulletin 311; Moore and others (n 293). See also Moore and Phillips (n 3) 53.

302

See, for instance, Kara Lavender Law and others, ‘Plastic Accumulation in the North Atlantic Subtropical Gyre’ (2010) 329 Science 1185; CJ Moore, GL Lattin and AF Zellers, ‘Density of Plastic Particles Found in Zooplankton Trawls from Coastal Waters of California to the North Pacific Central Gyre’, The Plastic Debris Rivers to Sea Conference, Redondo Beach, california, USA (2005); Peter G Ryan, ‘Litter Survey Detects the South Atlantic “Garbage Patch”’ (2014) 79 Marine Pollution Bulletin 220; Rei Yamashita and Atsushi Tanimura, ‘Floating Plastic in the Kuroshio Current Area, Western North Pacific Ocean’ (2007) 54 Marine Pollution Bulletin 485.

303

Law and others (n 302) 1186. For more information on the Global Ocean Drifter Program, see noaa Physical Oceanography Division, ‘Project Report 2017’ (noaa 2018) 9 <http://www.aoml.noaa.gov/phod/docs/PhOD_programs.pdf> accessed 19 February 2022.

304

See LCM Lebreton, SD Greer and JC Borrero, ‘Numerical Modelling of Floating Debris in the World’s Oceans’ (2012) 64 Marine Pollution Bulletin 653; Nikolai Maximenko, Jan Hafner and Peter Niiler, ‘Pathways of Marine Debris Derived from Trajectories of Lagrangian Drifters’ (2012) 65 Marine Pollution Bulletin 51. See also Kershaw and others (n 96) 22 and 24; iprc (International Pacific Research Center), ‘Tracking Ocean Debris’ (2008) 8 iprc Cimate 14, 16; unep, UNEP Year Book 2014: Emerging Issues in Our Global Environment (n 292) 49.

305

See, for instance, Cózar and others (n 297) 10240.

306

Slat and others (n 103) 39.

307

D d’A Laffoley and others, ‘The Protection and Management of the Sargasso Sea: The Golden Floating Rainforest of the Atlantic Ocean: Summary Science and Supporting Evidence Case’ (Sargasso Sea Alliance 2011) 9.

308

University of Rhode Island, ‘Subseafloor Sediment In South Pacific Gyre One Of Least Inhabited Places On Earth’ (ScienceDaily, 1 July 2009) <http://www.sciencedaily.com/releases/2009/06/090622171408.htm> accessed 19 February 2022.

309

See Lebreton and others (n 294).

310

See, for example Barnes and others (n 133); Cózar and others (n 297); Eriksen and others (n 297); ‘Plastic Pollution in the South Pacific Subtropical Gyre’ (2013) 68 Marine Pollution Bulletin 71; Galgani, Hanke and Maes (n 295); Hammer, Kraak and Parsons (n 102); Kara Lavender Law and others, ‘Distribution of Surface Plastic Debris in the Eastern Pacific Ocean from an 11-Year Data Set’ (2014) 48 Environmental Science & Technology 4732; Lebreton and others (n 294); Moore and others (n 293); Moore and others (n 302); Peter G Ryan, ‘The Characteristics and Distribution of Plastic Particles at the Sea-Surface off the Southwestern Cape Province, South Africa’ (1988) 25 Marine Environmental Research 249; ‘A Simple Technique for Counting Marine Debris at Sea Reveals Steep Litter Gradients between the Straits of Malacca and the Bay of Bengal’ (2013) 69 Marine Pollution Bulletin 128; ‘Litter Survey Detects the South Atlantic “Garbage Patch”’ (n 302); Yamashita and Tanimura (n 302). For a detailed overview of sampling studies on the abundance and distribution of marine (plastic) debris, see Slat and others (n 103) 42–47.

311

Cózar and others (n 297); Eriksen and others (n 297).

312

Barnes and others (n 133) 1995. cf ibid 1988.

313

Law and others (n 302) 1187.

314

Barnes and others (n 133) 1995. The fact that plastic abundance in the Southern Hemisphere is almost as high as in the Northern Hemisphere seems surprising, given that inputs are substantially higher in the Northern Hemisphere. Whether the balanced distribution between the Northern and the Southern Hemisphere is due to cross-equatorial movements of the particles or to unknown sources in the Southern Hemisphere is yet unclear: see Eriksen and others (n 297) 10.

315

Erik van Sebille, Matthew H England and Gary Froyland, ‘Origin, Dynamics and Evolution of Ocean Garbage Patches from Observed Surface Drifters’ (2012) 7 Environmental Research Letters 044040.

316

See Eriksen and others (n 297) 8; Olivia Gerigny and others, ‘Déchets en mer et sur le fond’, Plan d’action pour le milieu marin: Sous-région marine Méditerranée Occidentale: Évaluation initiale des eaux marines <http://www.dirm.mediterranee.developpement-durable.gouv.fr/IMG/pdf/Evaluation_initiale_des_eaux_marines_web.pdf> accessed 19 February 2022.

317

See Martin Thiel and others, ‘Spatio-Temporal Distribution of Floating Objects in the German Bight (North Sea)’ (2011) 65 Journal of Sea Research 368.

318

See Andrés Cózar and others, ‘The Arctic Ocean as a Dead End for Floating Plastics in the North Atlantic Branch of the Thermohaline Circulation’ (2017) 3 Science Advances e1600582.

319

See Peng Zhou and others, ‘The Abundance, Composition and Sources of Marine Debris in Coastal Seawaters or Beaches around the Northern South China Sea (China)’ (2011) 62 Marine Pollution Bulletin 1998.

320

According to Eriksen and others, differences in numbers when compared to the results of the circumnavigation from 2010/11 are due to the fact that Cózar and others focused on microplastics only: Eriksen and others (n 297) 10.

321

Kershaw and others (n 96) 21.

322

Hammer, Kraak and Parsons (n 102) 13.

323

Eriksen and others (n 297) 7.

324

See, for instance, Galgani, Hanke and Maes (n 295) 39.

325

See, for instance, Hammer, Kraak and Parsons (n 102) 13, estimating that while most fragments evenually sink towards the ocean floor, half of the remaining plastic debris is washed ashore.

326

E.g. Michiel Claessens and others, ‘Occurrence and Distribution of Microplastics in Marine Sediments along the Belgian Coast’ (2011) 62 Marine Pollution Bulletin 2199; AM Cundell, ‘Plastic Materials Accumulating in Narragansett Bay’ (1973) 4 Marine Pollution Bulletin 187; Trevor R Dixon and A Joy Cooke, ‘Discarded Containers on a Kent Beach’ (1977) 8 Marine Pollution Bulletin 105; Murray R Gregory, ‘Virgin Plastic Granules on Some Beaches of Eastern Canada and Bermuda’ (1983) 10 Marine Environmental Research 73; G Scott, ‘Plastics Packaging and Coastal Pollution’ (1972) 3 International Journal of Environmental Studies 35.

327

E.g. Gregory, ‘Virgin Plastic Granules on Some Beaches of Eastern Canada and Bermuda’ (n 326); Theodore R Merrell, ‘Accumulation of Plastic Litter on Beaches of Amchitka Island, Alaska’ (1980) 3 Marine Environmental Research 171; C Rosevelt and others, ‘Marine Debris in Central California: Quantifying Type and Abundance of Beach Litter in Monterey Bay, CA’ (2013) 71 Marine Pollution Bulletin 299.

328

E.g. Murray R Gregory, ‘Plastic Pellets on New Zealand Beaches’ (1977) 8 Marine Pollution Bulletin 82; ‘Accumulation and Distribution of Virgin Plastic Granules on New Zealand Beaches’ (1978) 12 New Zealand Journal of Marine and Freshwater Research 399; ‘Plastics and Other Seaborne Litter on the Shores of New Zealand’s Sub-Antarctic Island’ (1987) 7 New Zealand Antarctic Record 32.

329

In 2009, about 2,000 items of anthropogenic debris were estimated to strand on North Atlantic Ocean shores per linear kilometre per year, and about 500 items on South Atlantic Ocean shores. More than half of the debris is plastic: Barnes and others (n 133) 1988. See also DKA Barnes and P Milner, ‘Drifting Plastic and Its Consequences for Sessile Organism Dispersal in the Atlantic Ocean’ (2005) 146 Marine Biology 815.

330

There are reports of more than 100,000 items, especially plastic pellets, per square metre of beach sediment near Auckland, New Zealand: Gregory, ‘Accumulation and Distribution of Virgin Plastic Granules on New Zealand Beaches’ (n 328) 400; RC Thompson and others, ‘Plastics, the Environment and Human Health: Current Consensus and Future Trends’ (2009) 364 Philosophical Transactions of the Royal Society B: Biological Sciences 2153, 2154. In Bootless Bay, Papua New Guinea, debris densities of up to 78.3 items per square metre were reported, almost 90 per cent of which was plastic: Stephen DA Smith, ‘Marine Debris: A Proximate Threat to Marine Sustainability in Bootless Bay, Papua New Guinea’ (2012) 64 Marine Pollution Bulletin 1880, 1880. After a typhoon in 2009, 3,227 items were found in a random 100 metres × 5 metres beach transect in the south-west of Taiwan; 78.3 per cent of the items were plastic: Ta-Kang Liu, Meng-Wei Wang and Ping Chen, ‘Influence of Waste Management Policy on the Characteristics of Beach Litter in Kaohsiung, Taiwan’ (2013) 72 Marine Pollution Bulletin 99, 101. After a flooding event in the Turkish Western Black Sea also in 2009, beach litter densities of up to 5,058 pieces per square metre were reported, with over 90 per cent plastics: Eda N Topçu and others, ‘Origin and Abundance of Marine Litter along Sandy Beaches of the Turkish Western Black Sea Coast’ (2013) 85 Marine Environmental Research 21, 24. Densities of anthropogenic marine debris found in Chilean beaches and shores ranged from ten to over 250 pieces per kilometre. About 86 per cent of the debris was plastic: M Thiel and others, ‘Anthropogenic Marine Debris in the Coastal Environment: A Multi-Year Comparison between Coastal Waters and Local Shores’ (2013) 71 Marine Pollution Bulletin 307, 310.

331

Jennifer L Lavers and Alexander L Bond, ‘Exceptional and Rapid Accumulation of Anthropogenic Debris on One of the World’s Most Remote and Pristine Islands’ (2017) 114 Proceedings of the National Academy of Sciences 6052.

332

Galgani, Hanke and Maes (n 295) 33.

333

See, for instance, Topçu and others (n 330) 25.

334

Hammer, Kraak and Parsons (n 102) 15.

335

Galgani, Hanke and Maes (n 295) 33.

336

See Barnes and others (n 133) 1988, including references.

337

Hammer, Kraak and Parsons (n 102) 17.

338

Cózar and others (n 297) 10242; Eriksen and others (n 297) 11.

339

Lucy C Woodall and others, ‘The Deep Sea Is a Major Sink for Microplastic Debris’ (2014) 1 Royal Society Open Science 140317, 1. See also Lisbeth Van Cauwenberghe and others, ‘Microplastic Pollution in Deep-Sea Sediments’ (2013) 182 Environmental Pollution 495.

340

See Gregory and Andrady (n 133) 384–85, with references.

341

Cózar and others (n 297) 10241; Kershaw and others (n 96) 26.

342

See, however, F Galgani and others, ‘Litter on the Sea Floor Along European Coasts’ (2000) 40 Marine Pollution Bulletin 516; C Ioakeimidis and others, ‘A Comparative Study of Marine Litter on the Seafloor of Coastal Areas in the Eastern Mediterranean and Black Seas’ (2014) 89 Marine Pollution Bulletin 296; Andreas Koutsodendris and others, ‘Benthic Marine Litter in Four Gulfs in Greece, Eastern Mediterranean; Abundance, Composition and Source Identification’ (2008) 77 Estuarine, Coastal and Shelf Science 501; DI Lee, HS Cho and SB Jeong, ‘Distribution Characteristics of Marine Litter on the Sea Bed of the East China Sea and the South Sea of Korea’ (2006) 70 Estuarine, Coastal and Shelf Science 187; Juying Wang and others, ‘Chapter 25: Marine Debris’, First World Ocean Assessment (United Nations 2016) 397–98.

343

See Peter G Ryan, ‘A Brief History of Marine Litter Research’ in Melanie Bergmann, Lars Gutow and Michael Klages (eds), Marine Anthropogenic Litter (Springer 2015) 16, with references.

344

See Barnes and others (n 133) 1991. cf Hammer, Kraak and Parsons (n 102) 17.

345

Hammer, Kraak and Parsons (n 102) 17.

346

See Murray R Gregory, ‘Environmental Implications of Plastic Debris in Marine Settings – Entanglement, Ingestion, Smothering, Hangers-on, Hitch-Hiking and Alien Invasions’ (2009) 364 Philosophical Transactions of the Royal Society B: Biological Sciences 2013, 2017.

347

Barnes and others (n 133) 1987; Slat and others (n 103) 38.

348

Size classification varies among different studies. Nanoplastics, which represent the least known group of marine litter, are plastic particles that are less than 0.0001 mm in at least one of their dimensions. Microplastics usually comprise plastic fragments of sizes up to 0.2 or 0.5 cm, mesoplastics are up to 2 or 5 cm. The term macroplastics usually refers to items bigger than 2 or 5 cm. Large plastic objects of more than 50 cm are sometimes referred to as megaplastics: see Hammer, Kraak and Parsons (n 102) 5; Lebreton and others (n 294) 5.

349

Lebreton and others (n 294) 2; Eriksen and others (n 297) 9.

350

Barnes and others (n 133) 1985.

351

Microbeads are found in a wide range of personal care products such as toothpaste, shower gels and facial cleansers, but also in air-blast or sandblast cleaning media, sometimes replacing natural ingredients. In the absence of effective wastewater treatment, the microplastics are released directly to the ocean or other water bodies such as lakes and rivers: see unep, UNEP Year Book 2014: Emerging Issues in Our Global Environment (n 292) 50. cf who (n 69).

352

Julien Boucher and Damien Friot, ‘Primary Microplastics in the Oceans: A Global Evaluation of Sources’ (iucn 2017) 21; unep, ‘Mapping of Global Plastics Value Chain’ (n 90) 52. See also Edgar Hernandez, Bernd Nowack and Denise M Mitrano, ‘Polyester Textiles as a Source of Microplastics from Households: A Mechanistic Study to Understand Microfiber Release During Washing’ (2017) 51 Environmental Science & Technology 7036.

353

Conventional and advanced treatment in wastewater and drinking water systems can effectively remove microplastic particles. However, approximately 67 per cent of the population in low- and middle-income countries lack access to sewage connections and about 20 per cent of household wastewater collected in sewers does not undergo at least secondary treatment: who (n 69) xi, with references.

354

Patrick ten Brink and others, ‘Plastics Marine Litter and the Circular Economy: A Briefing by IEEP for the MAVA Foundation’ (ieep 2016) 4.

355

Kershaw and others (n 96) 22.

356

Lebreton and others (n 294) 12.

357

See Ocean Conservancy, ‘International Coastal Cleanup 2017 Report’ (2017) 13 <https://oceanconservancy.org/wp-content/uploads/2017/04/2017-Ocean-Conservancy-ICC-Report.pdf> accessed 19 February 2022. The 2016 International Coastal Cleanup involved 504,583 volunteers in 112 countries around the world, who removed 8,346 tonnes of debris (13,840,398 items) from 24,136 km of beaches and inland waterways.

358

Hammer, Kraak and Parsons (n 102) 6, with references.

359

See ibid 18; Galgani, Hanke and Maes (n 295) 39.

360

See Galgani, Hanke and Maes (n 295) 31; Yoshifumi Tanaka, The International Law of the Sea (2nd edn, Cambridge University Press 2015) 271–72.

361

See, for instance, ‘Montreal Guidelines for the Protection of the Marine Environment Against Pollution from Land-Based Sources’ (Decision 13/18/ii of the Governing Council of unep, of 24 May 1985) para 1(b); Gregory and Andrady (n 133) 382; Tanaka, International Law of the Sea (n 360) 270.

362

See Galgani, Hanke and Maes (n 295) 31.

363

Peter Sundt, Per-Erik Schulze and Frode Syversen, ‘Sources of Microplastics-Pollution to the Marine Environment’ (Norwegian Environment Agency 2015) M-321|2015 33–42; Yoshifumi Tanaka, ‘Regulation of Land-Based Marine Pollution in International Law: A Comparative Analysis between Global and Regional Legal Frameworks’ (2006) 66 Zeitschrift fuer Ausländisches Öffentliches Recht und Völkerrecht [Heidelberg Journal of International Law] 535, 553.

364

unga, ‘Report of the Secretary-General: Oceans and the Law of the Sea’ (2004) UN Doc A/59/62/Add.1 29 para 97; gesamp, ‘The State of the Marine Environment’ (n 283) 104 para 431; Daud Hassan, Protecting the Marine Environment from Land-Based Sources of Pollution: Towards Effective International Cooperation (Ashgate 2006) 15–16; Donald R Rothwell and Tim Stephens, The International Law of the Sea (2nd edn, Hart Publishing 2016) 366; Tanaka, ‘Regulation of Land-Based Marine Pollution’ (n 363) 535. According to the 1990 gesamp Report, 44 per cent of marine pollution can be attributed to land-based discharge, 33 per cent to atmospheric input from land, 12 per cent to maritime transport, 10 per cent to dumping and 1 per cent to oil exploration and production: gesamp, ‘The State of the Marine Environment’ (n 283) 88. Sea-based pollution sources together account for less than 20 per cent of marine pollution.

365

See Anthony L Andrady, ‘Microplastics in the Marine Environment’ (2011) 62 Marine Pollution Bulletin 1596, 1597; Galgani, Hanke and Maes (n 295) 31; Gregory and Andrady (n 133) 382; Lebreton, Greer and Borrero (n 304) 654; Michael Liffmann and Laura Boogaerts, ‘Linkages Between Land-Based Sources of Pollution and Marine Debris’ in James M Coe and Donald B Rogers (eds), Marine Debris: Sources, Impacts and Solutions (Springer New York 1997) 359. cf Jambeck and others (n 291) 768. The predominance of marine plastics from land-based sources is questioned by a 2019 study suggesting major debris inputs from ships, especially by dumped pet bottles from Chinese vessels: see Peter G Ryan and others, ‘Rapid Increase in Asian Bottles in the South Atlantic Ocean Indicates Major Debris Inputs from Ships’ [2019] Proceedings of the National Academy of Sciences 201909816.

366

Data from coastal clean-ups may therefore lead to overestimations of the portion of plastics from land-based sources: see Lebreton and others (n 294) 12.

367

See Boucher and Friot (n 352) 21; Barnes and others (n 133) 1986–87; Hammer, Kraak and Parsons (n 102) 6.

368

Boucher and Friot (n 352) 14.

369

ibid 24. See also Hernandez, Nowack and Mitrano (n 352); Sundt, Schulze and Syversen (n 363).

370

Jambeck and others (n 291) 768. cf unep, ‘Mapping of Global Plastics Value Chain’ (n 90) 53.

371

Jambeck and others (n 291) 768.

372

See Melanie Bergmann, Lars Gutow and Michael Klages, ‘Preface’ in Melanie Bergmann, Lars Gutow and Michael Klages (eds), Marine Anthropogenic Litter (Springer 2015) ix.

373

Including China, Indonesia, Philippines, Vietnam, Thailand, and Malaysia. Sri Lanka, Egypt, Nigeria, Bangladesh, South Africa and India are also considered major contributors. The United States rank twentieth: see Jambeck and others (n 291) 769. See also Cózar and others (n 297) 10240.

374

See Jambeck and others (n 291) 770.

375

cbd Secretariat, ‘Marine Debris: Understanding, Preventing and Mitigating the Significant Adverse Impacts on Marine and Coastal Biodiversity’ (McGraw-Hill Education, 2016) cbd Technical Series No 83 16.

376

Matthew Cole and others, ‘Microplastics as Contaminants in the Marine Environment: A Review’ (2011) 62 Marine Pollution Bulletin 2588, 2593; David W Laist, ‘Impacts of Marine Debris: Entanglement of Marine Life in Marine Debris Including a Comprehensive List of Species with Entanglement and Ingestion Records’ in James M Coe and Donald B Rogers (eds), Marine Debris (Springer New York 1997). See also Susanne Kühn, Elisa L Bravo Rebolledo and Jan A van Franeker, ‘Deleterious Effects of Litter on Marine Life’ in Melanie Bergmann, Lars Gutow and Michael Klages (eds), Marine Anthropogenic Litter (Springer 2015) 75–105, with references; unep and grid-Arendal, Marine Litter: Vital Graphics (2016) 15, with references.

377

The presence of ingested microplastics has been detected in amphipod populations in the Mariana Trench and other deep ocean trenches: see AJ Jamieson and others, ‘Microplastics and Synthetic Particles Ingested by Deep-Sea Amphipods in Six of the Deepest Marine Ecosystems on Earth’ (2019) 6 Royal Society Open Science 180667. Particularly high concentrations of microplastic particles have been found in arctic sea ice: see Ilka Peeken and others, ‘Arctic Sea Ice Is an Important Temporal Sink and Means of Transport for Microplastic’ (2018) 9 Nature Communications 1505.

378

See Chelsea M Rochman and others, ‘The Ecological Impacts of Marine Debris: Unraveling the Demonstrated Evidence from What Is Perceived’ (2016) 97 Ecology 302.

379

See Kershaw and others (n 96) 25.

380

See Kühn, Bravo Rebolledo and van Franeker (n 376) 76–83, with references. See also Geremy Cliff and others, ‘Large Sharks and Plastic Debris in KwaZulu-Natal, South Africa’ (2002) 53 Marine and Freshwater Research 575; Amanda Johnson and others, ‘Fishing Gear Involved in Entanglements of Right and Humpback Whales’ (2006) 21 Marine Mammal Science 635; Laist (n 376); J Orós and others, ‘Diseases and Causes of Mortality among Sea Turtles Stranded in the Canary Islands, Spain (1998–2001)’ (2005) 63 Diseases of Aquatic Organisms 13.

381

See, for instance, Derraik (n 287) 844–46; Cecilia Eriksson and Harry Burton, ‘Origins and Biological Accumulation of Small Plastic Particles in Fur Seals from Macquarie Island’ (2003) 32 Ambio 380; Ryan, ‘A Brief History of Marine Litter Research’ (n 343) 3–12.

382

Filter-feeding organisms, including different species of plankton, crustaceans, shellfish, fish and whales, obtain their nutrition by filtering large volumes of water, and thus are widely exposed to pelagic plastics. Microplastics have been identified as a threat to endangered surface-feeding baleen whales: see unep, UNEP Year Book 2014: Emerging Issues in Our Global Environment (n 292) 50.

383

Kershaw and others (n 96) 24; Peter G Ryan and others, ‘Monitoring the Abundance of Plastic Debris in the Marine Environment’ (2009) 364 Philosophical Transactions of the Royal Society of London B: Biological Sciences 1999; Lindsay C Young and others, ‘Bringing Home the Trash: Do Colony-Based Differences in Foraging Distribution Lead to Increased Plastic Ingestion in Laysan Albatrosses?’ (2009) 4 plos one e7623.

384

See Kühn, Bravo Rebolledo and van Franeker (n 376) 85.

385

Rochman and others, ‘The Ecological Impacts of Marine Debris’ (n 378) 303.

386

Kühn, Bravo Rebolledo and van Franeker (n 376) 85–95, with references.

387

Bergmann, Gutow and Klages (n 372) x.

388

Released substances include phthalates, brominated flame retardants, bisphenol A, formaldehyde, acetaldehyde, 4-nonylphenol and possibly polyfluoronated compounds, triclosan, phthalate plasticizers and lead heat stabilizers: see Kennedy Bucci and others, ‘Impacts to Larval Fathead Minnows Vary between Preconsumer and Environmental Microplastics’ [2021] Environmental Toxicology and Chemistry <https://onlinelibrary.wiley.com/doi/abs/10.1002/etc.5036> accessed 19 February 2022; Frederic Gallo and others, ‘Marine Litter Plastics and Microplastics and Their Toxic Chemicals Components: The Need for Urgent Preventive Measures’ (2018) 30 Environmental Sciences Europe <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5918521> accessed 19 February 2022; Chelsea M Rochman, ‘The Complex Mixture, Fate and Toxicity of Chemicals Associated with Plastic Debris in the Marine Environment’ in Melanie Bergmann, Lars Gutow and Michael Klages (eds), Marine Anthropogenic Litter (Springer 2015) 131, with references. See also Section 1.1.A.ii above.

389

Such as polychlorinated biphenyls (pcbs), polyaromatic hydrocarbons (pahs), hexachlorocyclohexane (hch), dichlorodiphenyldichloroethylene (dde), nonylphenol and phenanthrene. Because of their persistent, bioaccumulative and toxic characteristics, the European Union lists several of these chemicals as priority substances: European Parliament and Council Directive 2008/105/ec of 16 December 2008 on environmental quality standards in the field of water policy [2008] oj L348/84, Annex ii.

390

The sorptive capacity of a plastic particle and the rate at which chemicals are absorbed depend on the surface-to-volume ratio of the particle. In general, the effect is greater the smaller a fragment is. At the same time, smaller fragments enter the food chain more easily, thereby potentially transferring the chemicals to marine organisms: see Barnes and others (n 133) 1995.

391

Rochman and others, ‘The Ecological Impacts of Marine Debris’ (n 378) 303. See also Andrady (n 365) 1601–02; Emma L Teuten and others, ‘Transport and Release of Chemicals from Plastics to the Environment and to Wildlife’ (2009) 364 Philosophical Transactions of the Royal Society B: Biological Sciences 2027.

392

See Mark Anthony Browne and others, ‘Microplastic Moves Pollutants and Additives to Worms, Reducing Functions Linked to Health and Biodiversity’ (2013) 23 Current Biology 2388, 2388; Chelsea M Rochman and others, ‘Ingested Plastic Transfers Hazardous Chemicals to Fish and Induces Hepatic Stress’ (2013) 3 Scientific Reports 3263, 3–4; Chelsea M Rochman and others, ‘Early Warning Signs of Endocrine Disruption in Adult Fish from the Ingestion of Polyethylene with and without Sorbed Chemical Pollutants from the Marine Environment’ (2014) 493 The Science of the Total Environment 656.

393

Barnes and others (n 133); Rochman (n 388) 119, with references.

394

See Mark A Browne and others, ‘Ingested Microscopic Plastic Translocates to the Circulatory System of the Mussel, Mytilus Edulis (L)’ (2008) 42 Environmental Science & Technology 5026.

395

See ciel, ‘Plastic & Health’ (n 10) 52–55, with references; wwf, No Plastic in Nature: Assessing Plastic Ingestion from Nature to People (2019) 7–8.

396

Rochman (n 388) 130. cf who (n 69) 31–34.

397

See Rochman (n 388) 128, with references.

398

T Kiessling, L Gutow and M Thiel, ‘Biodiversity: Invasions by Marine Life on Plastic Debris’ in Melanie Bergmann, Lars Gutow and Michael Klages (eds), Marine Anthropogenic Litter (Springer 2015) 157. See also Stefano Aliani and Anne Molcard, ‘Hitch-Hiking on Floating Marine Debris: Macrobenthic Species in the Western Mediterranean Sea’ (2003) 503 Hydrobiologia 59; David KA Barnes, ‘Biodiversity: Invasions by Marine Life on Plastic Debris’ (2002) 416 Nature 808.

399

See Kühn, Bravo Rebolledo and van Franeker (n 376) 83–85, with references.

400

Henry S Carson and others, ‘Small Plastic Debris Changes Water Movement and Heat Transfer through Beach Sediments’ (2011) 62 Marine Pollution Bulletin 1708; Hammer, Kraak and Parsons (n 102) 16.

401

See Stephanie Newman and others, ‘The Economics of Marine Litter’ in Melanie Bergmann, Lars Gutow and Michael Klages (eds), Marine Anthropogenic Litter (Springer 2015) 368.

402

The natural capital cost of plastic includes costs related to a range of environmental impacts, including those on oceans and impacts related to greenhouse gas emissions released from producing plastic feedstock or the loss of resources when plastic waste is not recycled: see unep, ‘Valuing Plastic: The Business Case for Measuring, Managing and Disclosing Plastic Use in the Consumer Goods Industry’ (unep 2014) 7.

403

See ibid.

404

John Mouat, Rebeca Lopez Lozano and Hannah Bateson, ‘Economic Impacts of Marine Litter’ (kimo International 2010) 37–40.

405

ibid 43. It was estimated that removing litter from South Africa’s waste water streams would cost about US$279 million per year: see ten Brink and others (n 354) 22, including reference.

406

Yong Chang Jang and others, ‘Estimation of Lost Tourism Revenue in Geoje Island from the 2011 Marine Debris Pollution Event in South Korea’ (2014) 81 Marine Pollution Bulletin 49.

407

See P ten Brink and others, Guidelines on the Use of Market-Based Instruments to Address the Problem of Marine Litter (unep 2009) 22; Kershaw and others (n 96) 28.

408

Estimated damage cost across the 21 apec-Countries is US$364 million for the fishing industry, US$279 million for the shipping industry and US$622 million for the marine tourism industry: see Alistair McIlgorm, Harry F Campbell and Michael J Rule, ‘The Economic Cost and Control of Marine Debris Damage in the Asia-Pacific Region’ (2011) 54 Ocean & Coastal Management 643.

409

Newman and others (n 401) 372.

410

See Kershaw and others (n 96) 28. See also Mouat, Lopez Lozano and Bateson (n 404) 56–58.

411

It was estimated that the introduction of the carpet sea squirt (Didemnum vexillum) in Holyhead Harbour (Wales, UK) would have cost the local mussel fisheries up to €8.6 million in the next ten years if no mitigation measures were taken: Rohan Holt, ‘The Carpet Sea Squirt Didemnum Vexillum: Eradication from Holyhead Marina – Progress to October 2009’ (Presentation to the Scottish Natural Heritage Conference ‘Marine Non-native Species: Responding to the threat’, Battleby, UK, 27 October 2009). See also Newman and others (n 401) 369.

412

See Kershaw and others (n 96) 28; Newman and others (n 401) 371.

413

Newman and others (n 401) 375.

414

unep, ‘Combating Marine Plastic Litter and Microplastics: An Assessment of the Effectiveness of Relevant International, Regional and Subregional Governance Strategies and Approaches’ (2017) (unea-3 Legal Report) unep/ea.3/inf/5 99.

415

See Emma Watkins and others, ‘Marine Litter: Socio-Economic Study – Scoping Report’ (ieep 2015), summary.

416

unep, ‘UNEA-3 Legal Report’ (n 414) 98.

417

For more information on the concepts of intra- and intergenerational equity, see Section 2.1.A.ii.1) below.

418

See ten Brink and others (n 407) 22.

419

See Section 2.1.A.ii.2) in particular.

420

According to a study presented at the World Economic Forum 2016, oceans are expected to contain more plastics than fish (by weight) by 2050 in a business-as-usual scenario: World Economic Forum (n 13) 7.

421

Barnes and others (n 133) 1993.

422

See Jambeck and others (n 291) 770. See also unep, ‘Mapping of Global Plastics Value Chain’ (n 90) 17–18.

Footnotes

The figure shows crade-to-gate impact assessment results for seven polymers that are generated from fossil-fuel feedstocks (pet; pvc; hdpe; ldpe; ps; pc; pp), two bio-based polymers, each in two different varieties (polylactic acid made via a general process (pla-g) and a process reported by Nature-Works llc (pla-nw); polyhydroxyalkanoate derived from corn grain (pha-g) and from corn stover (pha-s)), as well as one hybrid bio/petroleum polymer (biopolyethylene terephthalate (b-pet)). Cradle-to-gate assessments only include impacts resulting from the production stage, but not from use or disposal. Ten different impact categories have been assessed.