Stranded debris of foamed plastic on the coast of Eta Island [Japan] and Kurahashi Island in Hiroshima Bay

Abstract

Expanded polystyrene (EPS) ‰oats are used abundantly for the ‰oats of oyster farming rafts in Hiroshima Bay. This paper investigated the occurrence of stranded debris of foamed plastics, stranding and unsuitable use of EPS ‰oats on the coast of Eta and Kurahashi Islands in the Bay. Stranded debris of foamed plastic was collected from sand samples of 34 sites. Stranded ‰oats on the beach and unsuitably used ‰oats without covers for mooring buoys and fenders on the sea were observed visually at 58 sites along 48.6 km of coastline. The total number of collected debris was 245,656 items. Plastics accounted for 99.9 of the total number. Foamed plastic fragments accounted for 99.5 of the total, the size of under 10.0 mm represented 98.5 of the fragments, and the average density was 44,521.3 pieces per m2. Unsuitably used ‰oats totaled 6,760, and the density was 140.7 pieces per harbor. The density of stranded ‰oats was 1.1 pieces per km. The densities of unsuitably used ‰oats, stranded ‰oats and foamed plastic fragments on the coast of Eta Island were higher than those of Kurahashi Island.