Insights from the GESAMP report(s) on microplastics

Transcription

1 Marine debris, plastics and microplastics an overview Insights from the GESAMP report(s) on microplastics 2 mm Example of primary microplastic particles manufactured for a purpose Images courtesy of Richard Thompson, University of Plymouth UK Example of secondary microplastic particles fragments of larger items The Joint Group of Experts on Scientific Aspects of Marine Environmental Protection

2 GESAMP Working Group 40: Sources, fate and effects of microplastics in the marine environment ( ) Emerging issues programme UNEA-2 April 2015 July/August 2016 May

3 Microplastics part of the continuum of plastic debris Example: expanded polystyrene < 5mm No agreed official definition < 100 nm nano-particles (Graphic from GESAMP 2015, inspired by Won Joon Shim, KIOST)

4 Land-based sources of microplastics sources of primary microplastics sources of secondary microplastics industrial/manufacturing uses plastic pellets industrial abrasives injection powders 3D printing powders PCPs vehicle tyres fabrics, clothing macroplastics accidental & operational losses tyre wear dust washing fibres fragmentation waterways waterways waterways ocean Improved collection & of & solid waste

5 Sea-based sources of microplastics sources of primary microplastics sources of secondary microplastics commercial shipping tourist cruises fisheries aquaculture recreational users tourist cruises accidental loss of pellets PCPs wear and tear of nets, ropes and other gear during use wear and tear of equipment during use textile fibres ocean Improved design & modified practices (ship loading, fishing gear design )

6 Secondary microplastics - fragmentation rate poorly quantified - varies with environmental compartment (GESAMP 2015)

7 Distribution of floating micro- and macro-plastics in the ocean number of particles/items mass of particles/items micro- macro- (Eriksen et al. 2014)

8 Many plastics do not float! Modelling the distribution of different types of plastic micro-particles (330 microns), introduced by rivers into the North Sea Seawater average density = Polyethylene (PE) Density = 0.91 Polystyrene (PS) Density = 1.05 Polyethylene terephthalate (PET) Density = 1.40 Surface waters (model layer 1) PE floats PS intermediate PET sinks Bottom waters (model layer 12) (Van der Meulen et al. 2015,EU MICRO project)

9 Impacts: Microplastics as a source of contaminants? Plastics absorb and desorb contaminants e.g. PCBs, DDT & other POPs Some plastics release chemical additives e.g. PBDEs PBDEs (polybrominated diphenyl ethers) - used as a flame retardant on textiles & as an additive in some plastic products, and are endocrine disrupters Short-tailed shearwaters, northern North Pacific Ocean Gut transfer of PBDE flame retardants from plastic to fatty tissue Kosuke Tanaka, Tokyo Univ. Agric. & Technol. Tanaka et al., 2013, Mar. Poll. Bull., 69,

10 Microplastics & seafood safety Microplastics found in a wide variety of fish and shellfish Actual risk Perceived risk consumer choice.. the uptake of plastic-associated chemicals in humans due to inadvertent ingestion of microplastics in seafood appears likely to be no more significant than other human exposure pathways of these chemicals. However significant knowledge gaps and uncertainties remain, particularly for nano-sized material, and this may justify a more precautionary approach. UNEP (2016)

11 Microplastics - key points: Many different sources and entry points (therefore multiple intervention points and measures needed) Distributed widely in the ocean (shorelines, seawater & seabed) Widespread uptake by biota potential effects Absorption and release of harmful chemicals potential effects Present in seafood - potential for consumer concern Potential for rafting/transfer of organisms Cannot be removed from the ocean prevention is the key!