Déchets marins et microplastiques

8. Conclusions

The source document for this Digest states:

7. General Conclusions of the GESAMP micro-plastics Workshop

1. We have very limited information on the quantities of micro-plastics entering the oceans or on the processes and time-scales leading to fragmentation and the production of micro-plastics by industry;
2. There is limited information about the potential long-term hazards of micro-plastics either due to their physical or chemical properties (intrinsic and absorbed PBTs);
3. There is a need for an assessment to follow on from UNEPs efforts and to collate the available scientific information and make recommendations that will be of use to the wide variety of policy, industry and societal organisations that have responsibility in this area;
4. Any assessment of micro-plastics must take full account of the overall marine debris and solid waste management problem arising from land and marine-based sources and activities.
5. Micro-plastics should be included in new and existing programmes of monitoring in marine habitats, especially National programmes and those of Regional Seas bodies.

8. Recommendations of the GESAMP micro-plastics Workshop

1. GESAMP should approach the sponsoring Agencies of GESAMP, and other relevant Bodies, with a request to consider sponsoring a GESAMP-led Working Group to conduct an assessment of micro-plastics in the coastal and open ocean.
2. The assessment should be complementary to, and embedded in, other assessments and initiatives tackling the problem of marine debris, including UNEP, UNEP Regional Seas, other Regional bodies, and national and Regional Administrations such as NOAA, and the EU. It should also feed in to the UNGA Regular Process and the GEF/UNEP/IOC Transboundary Waters Assessment Programme
3. Research priorities / Key research programmes
   1. Basic mapping of the pelagic and benthic environment to assess their global distribution, the form and relative abundance of different types of polymer;
   2. Sources of plastics need to be prioritized, e.g. coastal and land based sources, especially sewage treatment and riverine inputs as well as from shipping;
   3. The long-term implications of micro-plastics given the predicted increasing inputs, particularly with regard to the impact on marine organisms and accumulation along food chains; in the coming years;
   4. Modelling oceanographic parameters to define micro-plastic movement, including oceanic currents, weather, tides, wind, etc. to predict the way plastics move away from point sources and where they re-accumulate - this would also help to determine where to monitor;
   5. The degree to which micro-plastics accumulate in the sediment and the role of oceanic cycling in transferring micro-plastics from pelagic environment to sediments - some plastics have a greater density than water, and the pattern of deposition and the local and regional distribution for a range of particle densities is unknown;
   6. The significant factors in the breakdown of plastics, e.g. ageing, UV, physical fragmentation, bio-degradation - different plastics may be more durable and have different degradation behaviour depending on the environment (e.g. Fulmar stomach, coastal wave environment).
4. A global assessment should among other aspects focus on:
   1. developing methods for estimating the inputs of plastics to the oceans from land-based and maritime sources;
   2. clarifying rates of fragmentation and the production of (fragmented) microplastics;
   3. quantifying the amount of plastics and micro-plastics washed ashore, their composition, form, size and spatial distribution;
   4. determining the amount of plastics and micro-plastics in the water column and deposited on sea floor in the coastal zone and the oceans; and
   5. further exploration of the potential for the transfer of PBT’s from plastics to organisms and their biological effects.
5. As an indicator of the impacts of litter on marine environment, trends in the amount and composition of litter ingested by marine animals should be monitored.

Source & ©: ,  Proceedings of the GESAMP International Workshop
on micro- plastic particles as a vector in transporting persistent, bio- accumulating and toxic substances in the oceans. 28-30th June 2010, UNESCO-IOC,
Paris. 7. General conclusions and 8. Recommendations. P.51-53