北太平洋における漂流漂着微小プラスチック

抄録

Distribution and composition （items and size） of drifting micro plastics （1mm <） were investigated at 31sites between 10, Aug. and 22, Sep. 2012 on the sea surface of western and central North Pacific Ocean. And distribution and composition （items and size） of grounded micro plastics （1mm <） were investigated at 5 coasts （7 sites） between Jun. 2011 and Jun. 2013 on the beaches of west coast of North America and remote islands in the North Pacific Ocean. The Maximum density of drifting micro plastics was over 130,000 pieces per km2 on the central area of North Pacific Ocean, and the hard plastic fragment was the highest density in this area （average 75.4％）. The Maximum density of grounded micro plastics showed over 60,000 pieces per m2 on the beach of Island of Hawaii, and the hard plastic fragment was the highest density in these sites （over 80％）. Major items of micro plastics on the sea surface of the North Pacific Ocean were hard plastic fragments, and others were filmy plastic fragments, lines and fiber and resin pellets. They were recognized on the beaches of remote islands in the North Pacific Ocean and west coast of North America.