Marine Litter Plastics and Microplastics and Their Toxic Chemicals Components: The Need for Urgent Preventive Measures

Marine Litter Plastics and Microplastics and Their Toxic Chemicals Components

The Need for Urgent Preventive Measures'"

Frederic Gallo, Cristina Fossi, Roland Weber, David Santillo, Joao Sousa, Imogen Ingram, Angel Nadal and Dolores Romano


10.1 Background—Situation on Plastic and Related Chemical Contamination

and Impacts 160

  • 10.1.1 Plastics in the Ocean: Sources, Volumes, Trends 160
  • 10.1.2 Chemicals (POPs and EDCs) in Marine Litter Plastics: Fate in the

Marine Environment 163

  • 10.1.3 Potential Impacts on Marine Biodiversity 167
  • 10.1.4 Potential Impacts from Marine Plastics on Human Health 168
  • 10.1.5 Potential Impacts on Food Safety and Availability and

Economic Activity 169

10.2 Conclusions—Actions Needed and Potential Support by Chemical and

Waste Convention 170

10.2.1 Urgent Measures Needed on Production and Consumption of Plastics

and Waste Management 170

10.2.2 Potential Measures Suggested in the Framework of the Stockholm and Basel Conventions to Address Marine Litter; Contribution from

the Stockholm Convention on Persistent Organic Pollutants (POPsJ 172

  • 10.2.3 Contribution from the Basel Convention on Hazardous Wastes 173
  • 10.3 Future Activities to Address Marine Litter 174

References 174 [1]

Background—Situation on Plastic and Related Chemical Contamination and Impacts

Plastics in the Ocean: Sources, Volumes, Trends

Plastic marine litter is a mixture of macromolecules (polymers)'[2] [3] and chemicals, its size ranging from several meters to a few nanometers. It comprises such diverse items as fishing gear, agricultural plastics, bottles, bags, food packaging, taps, lids, straws, cigarette butts, industrial pellets, cosmetic microbeads, and the fragmentation debris coming from the weathering of all of them. It has become ubiquitous in all marine compartments, occurring on beaches, on the seabed, within sediments, in the water column and floating on the sea surface. The quantity observed floating in the open ocean represents only a fraction of the total input: over two-thirds of plastic litter ends up on the seabed, with half of the remainder washed up on beaches and the other half floating on or under the surface, so quantifying only floating plastic debris seriously underestimates the amounts of plastics in the oceans [1]. There are major concentration patches of floating plastics in all the five big ocean gyres, and there is evidence that even the polar areas are acting as additional global sinks of floating plastics [2].

The global production of plastics is following a clear exponential trend since the beginning of mass plastic consumption and production in the 1950s, and from a global production of 311 million tonnes in 2014, it is projected to reach around 1800 million tonnes in 2050 (Figure 10.1) [3]. The quantities of plastics leaking to the oceans on a global scale are largely unknown. Reliable quantitative estimations of input loads, sources and originating sectors represent a significant knowledge gap, but it is suggested that, every year, almost 8 million tonnes of plastic leak into the ocean. It is estimated that the ocean may already contain over 150 million tonnes of plastic [4], of which around 250,000 tonnes, fragmented into 5 trillion plastic pieces, may be floating at the ocean surface [5]. It has also been estimated that the global quantity of plastic in the ocean will nearly double to 250 million tonnes by 2025 [6],+ which likely also represents a pollutant load of millions of tonnes of chemical additives. It is estimated that, on average, around 80%-90% of ocean plastic comes from land-based sources, including via rivers, with a smaller proportion arising from ocean-based sources such as fisheries, aquaculture and commercial cruise or private ships. Of that 80%, three-quarters is estimated to arise as a result of the lack of efficient collection schemes and proper waste management facilities in the municipalities in many countries, with the remainder entering the marine environment from careless littering and leaks from within the waste management system itself (such as urban drains).[3]

In addition to the detrimental consequences that ingestion of plastics by marine biota may entail [8-10], worrying environmental consequences of marine litter also stem from microplastics (less than 5 mm in diameter) and nanoplastics (less than 100 nm in at least one of its dimensions), which could potentially affect marine biota both from their physical nature if ingested and by transfer of chemicals associated with them, including persistent organic pollutants (POPs) and endocrine disruptor chemicals (EDCs). Most micro- and nanoplastics originate from the degradation of macroplastics through different pathways, that is, photodegradation and other weathering processes of plastics that have leaked into

Global plastic production and future trends [3]; Marine Litter Vital Graphics- Cartographer

FIGURE 10.1 Global plastic production and future trends [3]; Marine Litter Vital Graphics- Cartographer: Maphoto/Riccardo Pravettoni. (Source: UNEP. Marine plastic debris and microplastics—Global lessons and research to inspire action and guide policy change).

the sea [1] (e.g., bags, bottles, lids, food packaging, etc.), from plastic pellets lost into the environment during production or freight processes, or from textile fibers coming from washing machine runoff [3,11].' They may also be present as deliberately manufactured plastic microbeads used as scrubbing agents or for other purposes that can be found in some personal care and cosmetic products. It has been estimated that in the US alone, even considering that all sewage is connected to tertiary waste water treatment plants (WWTP), and assuming a 99% efficiency of the sedimentation process, around 8 trillion microbeads [5]

may nevertheless be released into aquatic habitats every day. Furthermore, as the sludge of the WWTPs may subsequently be applied as fertilizer, part of the remaining 800 trillion microbeads may enter into soils and aquatic habitats via runoff [12].' Some wildlife may also contribute to the overall burden of microplastics when they ingest larger pieces of plastic, which are then broken up into smaller pieces in their guts and lost back into the environment in the form of microplastics. For example, fulmars (Fulmarus glacialis), a type of seabird, alone are estimated to reshape and redistribute annually about 6 tonnes of microplastics [13].

Uptake of microplastics through different mechanisms has been demonstrated in more than 100 marine species, from zooplankton to whales, including mussels, crabs, fish, planktivorous sharks, sea reptiles and seabirds. In some species, ingestion is reported in over 80% of individuals in sampled populations.[6] Organisms can ingest microplastics as food, whether unintentionally capturing them while filter- or deposit-feeding or mistaking them for prey when foraging, or even by ingesting prey containing microplastics, that is, trophic transfer [15]. In some species, microplastics can be taken into the body when they become entrapped by gill structures [16,17]. Microplastics and nanoplastics fall well within the size range of the staple phytoplankton diet of many zooplankton species, such as the Pacific krill. Fossi et al. [18] found that 56% of surface neustonic/planktonic samples from the Mediterranean Sea contained microplastic particles.

Microalgae attached to microplastics are assumed to be more easily captured by filter feeders than free microplastics in the water column [15]. After microplastics are assimilated into the organism, they accumulate in the gut, translocate into other tissues or are excreted, depending on the size, shape and composition of the particles. For example, fish fed with langoustines (Nepbrops norvegicus) containing polypropylene filaments were found to ingest but not to excrete the microplastic strands, further corroborating the potential for trophic transfer and ecological impacts [14,19,20].

Uncertainties remain regarding the extent of harm caused to marine species directly by ingestion of microplastics and over the contribution they make to overall exposures to hazardous chemicals. Some studies report little or no physical or chemical harm to marine biota [21], while others including the use of the thermodynamic approach and the simulation of physiological conditions in the gut, suggest that chemicals in plastics might be released to organisms after ingestion [22-25]. In mussels, Mytilus galloprovincialis, exposed to microplastics (polyethylene and polystyrene) contaminated with polyaromatic hydrocarbons, marked bioaccumulation of these chemicals was recorded in both the digestive gland and gills [26], similarly in tidal flat organisms such as lugworms, Arenicola marina, exposed to microplastics with adsorbed pollutants (nonylphenol and phenanthrene) and additive chemicals (Triclosan and PBDE-47) [24]. Endocytosis5 of plastic nanoparticles can also result in adverse toxic endpoints [1,19].

Microplastics move with currents, wave action and wind conditions and can be found throughout all marine compartments. Modeling the dynamics and fate of micro- and nanoplastics in the marine environment is a complex and uncertain task since particles initially at the sea surface can sink to sediments, accelerated by biofouling, ageing, etc., while those already in sediments can potentially become remobilized to the water column by bioturbation, resuspension or hydrodynamic conditions and translocation by marine organisms [15]. It is remarkable that benthic microplastics are far more widespread than previously assumed, with accumulation trends matching the increasing production of plastics worldwide [1,15,20].

In the Mediterranean Sea, marine litter has become a critical issue, as this is a region known to be accumulating a high concentration of plastics [27-29]. This is due to interaction of a number of factors, including the hydrodynamics of this semi-closed sea (from which outflow mainly occurs through deep water currents), combined with a lack or deficit of environmentally sound urban waste management and proper and efficient collection systems of much of the waste generated in many of its riparian countries and heavily populated coastal areas.

Other areas of particular concern include mid-ocean islands close to gyres and the Small Island Developing States (SIDS), where the situation has been depicted as “waste disaster” [30]. In addition to the challenge of marine litter, these States face serious deficiencies in basic waste management capabilities, due mainly to small and sparse populations with limited potential economies of scale. There is also a shortage of land for sanitary landfill, with waste often being disposed of casually by burial, burning or discard into the surrounding land and sea. Furthermore, consumption patterns are changing over time, with an increasing number of tourists and more plastic waste being generated overall. The state and pace of economic and social development in these small and remote countries, faced with growing populations and increasing urbanization and with limits to infrastructure and to both human and natural resources, make combatting this growing threat to their supporting ecosystems and means of life extremely challenging [3].

At a global level, UNEP has estimated the economic impact of marine plastics (excluding microplastics), including losses incurred by fisheries and tourism due to plastic littering, as well as beach clean-up costs, at around $13 billion per year [31].

  • [1] This is an open access article. Previously published in Environ Sci Eur (2018) 30:13. © The Author(s) 2018. This article is distributed under the terms of the CreativeCommons Attribution 4.0 International License (http://creativecommons.Org/licenses/by/4.0/), whichpermits unrestricted use, distribution, and reproduction in any medium, provided you give appropriatecredit to the original author(s) and the source, provide a link to the Creative Commons license, and indicateif changes were made.
  • [2] Other exogenous causes are natural disasters such as floods, hurricanes and tsunamis.
  • [3] * Among the most common polymers found in the marine environment are low density polyethylene (PE-LD), linear low-density polyethylene (PE-LLD), high-density polyethylene (РЕ-HD), polypropylene (PP),polyethylene terephthalate (PET), polystyrene (PS) and polyvinyl chloride (PVC). f The total estimated biomass of fish of 10 g per individual and upward in the oceans is 529 million tonnes[7], which puts the magnitude of the problem of plastics in the oceans into perspective.
  • [4] * Among the most common polymers found in the marine environment are low density polyethylene (PE-LD), linear low-density polyethylene (PE-LLD), high-density polyethylene (РЕ-HD), polypropylene (PP),polyethylene terephthalate (PET), polystyrene (PS) and polyvinyl chloride (PVC). f The total estimated biomass of fish of 10 g per individual and upward in the oceans is 529 million tonnes[7], which puts the magnitude of the problem of plastics in the oceans into perspective.
  • [5] There are other sources of polymers that are not considered in this paper such as cigarette butts, tire androad wear and artificial turf infill.
  • [6] 2 This was a strong argument for the law banning microbeads in cosmetics and personal care products in theUS in 2015 (Microbead-Free Waters Act). * Of the sampled crustacean Nepbrops norvegicus in the Sea of Clyde (Scotland), 83% contained plastics(predominately filaments) in their stomachs [14].
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