Mikroskopiska plastpartiklar i havet: ursprung och effekter i marin miljö

Report, 2011

The issue of microscopic plastic particles was reported in Swedish media in 2008 after records of high concentrations in the sea along the Swedish west coast. This study compiles existing information about microscopic plastic particles in the oceans with the purpose to investigate their extent, origin and observed and potential effects on marine organisms. The results show that studies have been conducted since the 1970s, but that it still is an inadequately studied environmental issue. Contemporary studies have shown a globally widespread and increasing distribution of plastic particles in the oceans. Norén (2007) found that the particles were much smaller and far more by number than indicated in previous studies. The results further show a separation of plastic particles in two size intervals; microscopic plastic particles (<0.5 mm) and plastic particles (0.5-5 mm). It was assumed in several studies that plastic particles originate from larger plastic objects that have been fragmented in the ocean. There were divided opinions whether particles less than 0.5 mm are formed by fragmentation or not. No conclusion on the maritime industry’s share of the microscopic particles in the ocean could be drawn, though two studies showed that microscopic plastic fibers were greater in areas with high pleasure craft traffic. Furthermore, three studies were presented that gave indications on the effects of plastic particles on marine organisms. The first showed that plastic particles are eaten by sea cucumbers (Holothuroidea) in a far greater extent than expected. The second showed that microscopic plastic particles are accumulated and transported from the gut of blue mussels (Mytilus edulis) to their circulatory system. The third study showed that organic pollutants can be transferred from plastic particles to lugworm (Arenicola marina). It was concluded that microscopic plastic particles in marine environments are uptaken by marine organisms, but that it is unclear whether it results in adverse effects. The importance of further studies is emphasized, because the smaller the plastic particles are, the risk of accumulation in the tissues of an organism increases. It was further emphasized that policy-makers should focus on preventive measures.