海洋垃圾污染chapt8.pdf

PlaSTIC d EbRIS IN THE OCEa N UNEP Year Book 2014 emerging issues update Plastic Debris in the Ocean plastics debris Continous flows of plastic to the marine environment Every year large amounts of plastic debris enter the ocean 80 from both land- and sea-based activities, such as fisheries and 60 tourism, and poor waste management. While the total amount 40 in the ocean is unknown, plastic is found all over the world 20 including in the polar regions, far from its source. 0 Floating plastic can be transported great distances by ocean -20 currents. Although plastic debris is most commonly observed -40 on shorelines, it also accumulates in mid-ocean ‘gyres’, natural -60 circulation features that tend to trap floating material. Some 0 50 100 150 200 250 300 350 400 of the material sinks to the ocean floor, where it remains out 0.01 4 © IPRC 2 6 8 10 of sight. Environmental damage due to plastic debris is well documented. It includes: Gyres • Mortality or sub-lethal effects when plastic is ingested by animals such as turtles, small-toothed whales and seabirds Marine debris is subject to transport by ocean curre