Policies to Reduce Microplastics Pollution in Water

Executive summary

Microplastics pollution is one of the most pervasive emerging environmental issues. Tiny plastic fragments, particles and fibres now widely contaminate oceans, freshwaters, soils and air. Once in the environment, microplastics may continue to fragment into smaller particles and persist for a long time. Aquatic species, from plankton to large mammals, as well as humans are commonly exposed to microplastics via ingestion or inhalation.

A myriad of emission sources contribute to microplastics pollution. Examples are accidental industrial spillages, the discharge of microplastics intentionally added to products (e.g. rinse-off cosmetics and detergents) and the wear and tear of synthetic products (e.g. synthetic textiles, vehicle tyres) occurring during their use. Up to 3 Mt of microplastics enter the environment every year. Additionally, the degradation of plastic waste discarded into the environment further contributes to microplastics pollution.

Microplastics pollution is a reason of concern for water quality, potentially affecting ecosystems and human health. Laboratory experiments have shown that microplastics ingestion can induce adverse health effects in aquatic biota, although large uncertainties persist with regards to the thresholds at which risks may occur. Concerns are mainly driven by the presence in plastics of toxic chemicals and known or suspected endocrine disrupting additives, as well as by the potential for microplastics to sorb persisting organic pollutants from the environment. Although data gaps hinder reliable risk assessments, the persistence of plastics and the projected fast and continued increases in pollution levels call for policy measures to mitigate current and future risks to ecosystems and human health.

In recent years, microplastics pollution prevention has gained increasing policy attention in OECD countries. Attaining resource productivity, managing plastics in a sustainable way, preventing leakage to the environment and preserving water quality are key elements of environmental policy objectives in OECD countries, as also reflected in Sustainable Development Goal targets 6, 12 and 14.1. The OECD Council Recommendation on Water calls for Adherents to prevent, reduce and manage water pollution from all sources, while paying attention to pollutants of emerging concern, such as microplastics.

Recent policy action – notably restrictions on single-use plastics and microbeads in rinse-off cosmetics, and improved waste management practices – may contribute to reducing some plastic uses and mitigating leakage to the environment. However, the emission of microplastics from the wear and tear of products is a complex issue that remains largely untargeted by current policy frameworks, despite accounting for a substantial share of releases. Furthermore, while the leakage of plastic waste mainly occurs in emerging economies, OECD countries contribute substantially to the emission of microplastics. North America, Western Europe and Japan alone account for almost a third of direct microplastics releases, of which the abrasion of tyres and synthetic clothing account for 62%. In this context, several OECD countries are increasingly looking for solutions to better control these emissions.

This report develops policy insights on how to minimise microplastics emitted unintentionally from products and their potential impacts on human health and ecosystems. It assesses the feasibility and relevance of available mitigation measures for microplastics pollution of marine and freshwater environments, with a focus on textile products and vehicle tyres, which contribute to between one-half and two-thirds of microplastics releases into the environment (excluding the degradation of leaked plastics).

Microplastics emissions occur and are influenced by several stages of the lifecycle of textiles and tyres. As such, a broad range of entry points exist for the implementation of mitigation measures, including via:

• Source-directed approaches, such as the sustainable design and manufacturing of textiles, tyres, and complementary products (i.e. washing machines, laundry detergents, road surfaces and vehicles), to minimise the tendency of products to contribute to microplastics generation;

• Use-oriented approaches, such as the uptake of best use practices (e.g. laundering parameters, eco-driving) and mitigation technologies (e.g. microfibre filters), to reduce preventable releases;

• End-of-life approaches, such as improved waste management practices, to prevent waste leaking into the environment and potentially contributing to microplastics generation;

• End-of-pipe approaches, such as improved wastewater, stormwater, and road runoff management and treatment, to retain the emitted microplastics before these reach water bodies.

Policy insights: a lifecycle, holistic approach to close knowledge gaps and exploit synergies across different policy areas

Given the degree of persisting uncertainty and the potential for widespread ecosystem and human health impacts of microplastics, effective mitigation action is recommended. Mitigation action should be proportional, consistent with existing policy frameworks, based on adequate cost-benefit analysis considerations, and sufficiently flexible to encourage scientific research and innovation in mitigation solutions. Where microplastics pollution mitigation brings additional costs, attention will need to be paid to their fair allocation and to ensuring that responsibility for the implementation of mitigation measures is shared among stakeholders along the textile/apparel and tyre value chains.

The most cost-effective way to tackle the issue is likely the implementation of a mix of policy tools targeting several mitigation entry points along the lifecycle of products. Measures aimed at minimising the emission of microplastics at source are likely to have the largest mitigation potential. Especially for diffuse sources of pollution (e.g. tyre wear particles, airborne textile microfibres), prevention is often more cost-effective than treatment/restoration options downstream. At the same time, given the variety of entry pathways, measures upstream cannot entirely alleviate the risk of microplastics pollution of the water cycle. Thus, upstream intervention will need to be supplemented by effective end-of-pipe solutions.

The control and management of microplastics released from products is likely to require a strategic prioritisation among possible interventions as well as a consideration of their full impacts. Research has identified several mitigation practices and technologies implementable at different stages of the lifecycle of textiles and tyres, yet often further research and data is required to assess their cost-effectiveness, implementation feasibility, and potential for unintended consequences or trade-offs with other policy objectives. Policy options targeted to consumers (e.g. reduction in textile consumption, changes in driver behaviour) would benefit from further investigation of the likelihood of behaviour change occurring.

Although microplastics pollution alone is unlikely to drive costly investment decisions or to justify trade-offs with other relevant policy objectives, there are important gains to be made by exploiting or adapting existing measures in other policy areas. For instance, reductions in passenger vehicle use and shifts towards more sustainable transport modes, generally driven by a need to reduce GHG emissions and air pollution, can also contribute to mitigating microplastics emissions from road transport. Similarly, certain end-of-pipe mitigation options, such as improved wastewater treatment technologies or nature-based solutions, primarily designed to manage other risks (e.g. other pollutants, flooding), can generate significant co-benefits for microplastic mitigation.

Taking into consideration the points above, the following guidance emerges for policy action to manage textile- and tyre-based microplastics pollution:

• Further research is required in order to reduce data gaps as regards the toxicity of microplastics to wildlife and humans, perform more robust risk assessments for microplastics in different environmental media, and inform cost-benefit analyses for mitigation interventions. International and interdisciplinary cooperation and information sharing will be key to the advancement of research and to the standardisation and harmonisation of test methods (providing for variability of locations and research sites), such as test methods for the rate of microfibre shedding and tyre tread abrasion. Further, the development of common databases can reduce time and costs associated with documenting robust policy decisions at national and international levels.

• In the short term, significant progress in microfibre and tyre and road wear particle emission mitigation can be achieved by focusing on “no-regrets” mitigation options. These include good practices and technologies which have low implementation costs and low risk for potential unintended consequences (such as environmental burden shifting) and/or which generate co-benefits aligned with other environmental policy objectives, such as those addressing the environmental impacts of the textile and apparel sector and of road transport, climate change mitigation, air quality legislation, and improvements in water quality.

• When information on the effectiveness of mitigation measures has improved, additional and more specific policy measures will be needed to mandate, incentivise or encourage the uptake of mitigation technologies and best practices. Some of these policy measures, such as requirements to add microfibre filters to washing machines and consumer-awareness initiatives, are already being explored by governments.