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Recent reports and initiatives on plastic and micro-plastic waste at sea

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Context - Plastic waste is a growing issue: plastic production is projected to double over the next decade, and without a planning for the effective management of waste, the social, economic and environmental impact is also projected to increase.

However, over the last several years, many initiatives were taken at all levels to set up strategies and means to manage this complex issue.

This is a faithful synthesis and summary of several scientific consensus reports. For the full list of sources, see the references.

Latest update: 15 February 2019

1. Introduction

Today, we are inundated by plastic waste as a result of our careless approach to the use and, more so, the lack of planning for the post-use life of this durable material, which has been accompanied by a significant social, economic and ecological cost. Since in the next 10-15 years global plastic production is projected to nearly double, manufacturing, distribution, consumption and trade systems for plastic, absolutely need thus to be changed.

Most marine litter consists of material that degrades slowly, if at all, so a continuous input of large quantities of these items results in a gradual build-up in the marine and coastal environment. This negative trend has been confirmed by a number of studies in various regions, clearly indicating that the situation with regard to marine litter is continuously getting worse. Marine litter is thus not only an environmental but also a health, economic and aesthetic problem.

2. What is marine litter?

Marine litter is defined by the United Nations Environment Programme (UNEP) as “any persistent, manufactured or processed solid material discarded, disposed of, or abandoned in the marine and coastal environment.” It consists of things lost or discarded by people in seas, rivers, on beaches, or brought in by storm water, wastewater or wind, or of things like fishing nets and lost cargo.

It is estimated that more than 150 million tonnes of plastics have accumulated in the world's oceans and that:

  • 50% of consumer plastics are single use;
  • 10% of all human-generated waste is plastic;
  • 500 billion plastic bags are used each year;
  • 1 million plastic bottles are bought every minute;
  • 13 million tonnes of plastic leaks into the ocean each year;
  • 100,000 marine animals are killed by plastic waste each year.
EU Platic Waste Generation in 2015

Marine litter can be transported over long distances with ocean currents and winds and therefore is found in all seas and in remote areas; e.g., on islands in the middle of oceans, and in the polar regions.

3. What about plastic microparticles?

As described in the UNEP report on the “global lessons”1, microplastics are routinely defined as small particles or fragments of plastic measuring less than 5 mm in diameter. Others are purposefully manufactured for industrial and domestic goals. Some are the result of the weathering and fragmentation of larger plastic objects (from synthetic textile fragments, plastic particles used in cosmetic, or industrial cleansers, etc.), a process that is enhanced by exposure to UV irradiation but which becomes extremely slow once plastic sinks below the surface. Even plastics marked as ‘biodegradable’ do not degrade rapidly in the ocean. Nanometer-sized plastics are probably as common as milli- and micrometer-sized plastics, yet their hazards are less understood and may be more complex. The primary sources of macroplastic losses stem from mismanaged municipal solid waste (MSW) (i.e. open dumping and inadequate landfilling), accounting for about half of the macroplastics lost to the environment primarily from Africa, Latin America and the Caribbean, and the Middle East, which all have a high level of plastic consumption and harbor a large fraction of inadequately managed MSW. The quantities and types (size, shape, density, chemical composition) of materials, together with the entry points to the ocean, will determine to a great extent the subsequent distribution and impact.

Meanwhile, the losses of microplastics are mainly driven by large population and per-capita plastic consumption. The most contributing regions are North America, China, Asia (excluding Japan, India, and China), and Western Europe.

1 Marine plastic debris and microplastics – Global lessons and research to inspire action and guide policy change.
United Nations Environment Programme, Nairobi. UNEP (2016). 

4. What are the main environmental issues raised by marine litter?

Marine litter threatens marine and coastal biological diversity in productive coastal areas causing damage and death to wildlife. Entanglement in lost fishing nets and ingestion are the primary kinds of direct damage to wildlife caused by marine litter to marine organisms such as barnacles and lugworms, which eat pieces of macroplastics. Other threats to wildlife and the environment from marine litter include smothering of the seabed, and disturbance of habitats from mechanical beach cleaning.

Marine litter is also increasingly believed to be a source of accumulation of toxic substances in the marine environment and of ecosystems changes due to the transport of invasive species between seas, such as harmful algal blooms, and of pathogens. For the GESAMP report2 however, it is not clear whether, at the currently observed increase in number of microplastics, this is significant at a population level.

Each year, the presence of marine litter also results in damage that results in health risks and loss of life, loss of property and livelihood but also high economic costs. In addition, marine litter spoils, fouls and destroys the beauty of the sea and of the coastal zone.

2 Sources, fate and effects of microplastics in the marine environment: part two of a global assessment. GESAMP (2016).

5. Is there an established human health impact of microplastics originating from marine litter?

Plastic waste, and in particular plastics of medical and sanitary origin, ingested by marine organisms (fish, crustaceans, etc.) could be a health risk and potentially cause serious damage. In general, it is thought that only the smallest particles (1.5 μm or less) of these plastics can enter the capillary vessels of the organs and that the others will be excreted. Some of these microplastics are suspected of being able to interact then with the immune system, cause oxidative stress, or cause damage to DNA.

Nevertheless, there are many gaps in knowledge, such as toxicological data on microplastics currently ingested, their potential impact from cooking or high-temperature processing of fishery foods, and specific routes of absorption, distribution and translocation of these microplastic particles in tissues and organs of the human body.

According to a recent report from the Food and Agriculture Organization of the United Nations (FAO), on the fate of plastics in the human body and their potentially harmful effects on health3 , much remains to be done and, based on currently available scientific evidence, microplastics do not appear to pose a significant threat to food safety, as the health benefits associated with the consumption of fishery products outweigh the potential risks.

3 Microplastics in fisheries and aquaculture - Status of knowledge on their occurrence and implications for aquatic organisms and food safety. 2017 - Food and Agriculture Organisation of the United Nations (FAO)

6. What are the main obstacles to solving the problem of marine litter?

One of the major reasons to the marine litter problem, which appears to increase worldwide, are littering practices from the shipping sector, as well as lack of land-based infrastructure to receive litter, combined with a lack of awareness among main stakeholders and the general public. The Analytical Report on marine litter of the UNEP4 underlined that among the main contributions to the problem in this context were deficiencies in the implementation and enforcement of existing international and regional environment-related agreements, as well as national regulations and standards.

4 Marine plastic debris and microplastics – Global lessons and research to inspire action and guide policy change. United Nations Environment Programme, Nairobi. UNEP (2016). 

7. What are the main initiatives taken to manage plastic waste and marine litter?

The most urgent short-term solution to reduce plastic inputs, especially in developing economies, is to improve waste collection and management. Resolution 3/7 on marine litter and microplastics, adopted at the 3rd session of the United Nations Environment Assembly, calls on all countries and other stakeholders to use plastic responsibly, while striving to reduce the unnecessary use of plastic and promote the research and application of environmentally friendly alternatives. The problem is that marine litter is not always specifically mentioned in global or regional conventions, agreements or plans of action. Long-term solutions include improved governance at all levels, as well as behavioural and system changes, such as a more circular economy and more sustainable patterns of production and consumption.

At the same time, a wide range of marine litter-related instruments already exist and actions are underway at the global and regional levels. Education, information and training are therefore among the essential components of all the efforts to be made to promote a more rational reflection on waste in general in society. In practical terms, the plastic bag bans in place in more than 100 countries show how powerful direct government action can be on plastics.

In order to avoid marine litter coming more specifically from maritime transport, offshore platforms and fishing vessels, efforts must be made to reduce the generation of waste and their dissemination, which must be stored on board and landed ashore in an appropriate reception facility. All equipment and materials for fishing, especially driftnets, should be tagged for retrieval if lost at sea. No fishing gear should ever be deliberately discarded at sea but carried ashore for appropriate disposal.

Degradable plastics are also under development, which could help reduce the amount of persistent plastics in the environment, but could also send a bad signal to people and would be quite inconsistent with the many attempts to change the behaviour patterns of consumers. And if a contamination of the environment by some litter considered as a "compatible waste" was deemed acceptable, it would be very difficult to draw a line of demarcation and materialize a consistent change in attitude and behaviors.

At European level, the establishment of monitoring programs is an important step in the implementation of the 2008 Marine Strategy Framework Directive (MSFD - 2008/56 / EC). This involved developing a "Guide to Monitoring Marine Litter in European Seas". The pollution of the seas by plastics and microplastics has also become one of the three main areas of the European Strategy for Plastics in a Circular Economy5 adopted by the European Commission in January 2018.


8. What challenges do developing countries face to deal with marine litter issues?

Developing countries face difficulties related to capacity-building, resource mobilization and lack of alternatives in replacing certain types of plastics. Small island developing States are particularly vulnerable to the problem of marine plastic litter and microplastics, and face significant challenges with regard to waste management and plastic pollution. These States therefore need international support to deal with the problem, as well as more awareness raising programmes on marine litter and microplastics, especially for the most vulnerable populations.

Main reports referenced

Marine plastic debris and microplastics – Global lessons and research to inspire action and guide policy change. 2016. United Nations Environment Programme (UNEP), Nairobi.
Our Oceans, Seas and Coasts - Descriptor 10: Marine Litter E.U. Commission 
Combating marine plastic litter and microplastics: an assessment of the effectiveness of relevant international, regional and sub-regional governance strategies and approaches
Guidance on Monitoring of Marine Litter in European Seas. A guidance document within the Common Implementation Strategy for the Marine Strategy Framework Directive
MSFD Technical Subgroup on Marine Litter. E.U. Joint Research Centre -Institute for Environment and Sustainability (2013)
Sixth International Marine Debris Conference, San Diego, 2018 
Sources, fate and effects of microplastics in the marine environment: a global assessment.
(Kershaw, P. J., ed.). (2015). (IMO/FAO/UNESCO-IOC/UNIDO/WMO/IAEA/UN/UNEP/UNDP Joint Group of Experts on, Rep. Stud. GESAMP No. 90, 96 p.
Microplastics in fisheries and aquaculture - Status of knowledge on their occurrence and implications for aquatic organisms and food safety.
(2017) Food and Agriculture Organisation of the United Nations (FAO).
 Summary of Expert Discussion Forum on Possible Human Health Risks from Microplastics in the Marine Environment - US-EPA (2015)
Marine Litter - An analytical overview – UNEP (2005) 
World Environment Day 2018: Overview  
 First meeting of the Ad Hoc Open-Ended Expert Group on Marine Litter and Microplastics
Second meeting of the Ad Hoc Open-Ended Expert Group on Marine Litter and Microplastics.
UN Environment, December 2018 
A European Strategy for Plastics in a Circular Economy
COM/2018/028 final 
Further Reading:

2018 Ministerial declaration of the United Nations Environment Assembly at its third session: Towards a pollution-free planet

2018 UNEA Resolution 3/7: Marine litter and microplastics

2017 Pollution Report of the Executive Director

2017 General Assembly Resolution 71/312: Our ocean, our future: call for action 

2016 UNEA Resolution 2/11: Marine plastic litter and microplastics

2016 Report: Marine Plastic Debris & Microplastics: Global Lessons and Research to Inspire Action and Guide Policy Change 

2014 Marine Litter study to support the establishment of an initial quantitative headline reduction target

2018 A European Strategy for Plastics in a Circular Economy 

Plastic Pollution Facts and Figures 

Themes covered
Publications A-Z

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