Déchets marins et microplastiques

1. Introduction: plastic waste and micro-plastics in the oceans.

Global production of plastics is increasing every year (245 million metric tonnes in 2008) and the amount of plastic litter that is finding its way into the environment and into the oceans is also increasing, especially in the areas of the world where waste management practices are not keeping up with the rapid development.

There is however a lack of information on how much plastic debris finds its way to the oceans and how much of it there already is in the oceans. In order to identify the information needs and to explore what is already known and being done in the world, a workshop was held by the GESAMP (Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection) which is sponsored by nine UN agencies that have jurisdiction over the oceans. This workshop’s participants represented the scientific community, the plastics industry, policy makers and environmental NGOs, as well as regional bodies and developing as well as developed countries.

The initial focus of this workshop was on plastic particles as a vector in transporting persistent, bioaccumulating and toxic (PBT) substances. These plastic particles, or micro-plastics, result largely from the presence of plastic debris in the marine environment and, in turn, are directly related to the quantities of solid waste entering the oceans from land- and sea- based sources.

Once in the sea, a long-term process of transport and deterioration links our global and regional efforts in solid waste management with the occurrence of micro-plastics in the oceans. This process is impossible to influence except by controlling the amount of waste that enters the oceans. The workshop therefore surveyed the broader context of solid waste management, plastic waste recovery and recycling, as well as the behaviour of plastics in the marine environment.

Once in the sea, a long-term process of transport and deterioration links our global and regional efforts in solid waste management with the occurrence of micro-plastics in the oceans. This process is impossible to influence except by controlling the amount of waste that enters the oceans. The workshop therefore surveyed the broader context of solid waste management, plastic waste recovery and recycling, as well as the behaviour of plastics in the marine environment.

In recent years the existence of micro-plastics and their potential impact has received increasing attention. This concerns particles smaller than 5 mm, and particles as small as 1 μm (0,001 mm) have been identified. There is increasing evidence that such particles can be ingested by marine organisms, with the potential for: physical disruption and abrasion; toxicity of chemicals in the plastic; and, toxicity of absorbed persistent , bioaccumulating and toxic (PBT) substances. However, the available information is still scarce, experimental studies are few and far between and most of the ocean and coastal areas remains un-sampled. More...