Marine pollution: Charting the plastic waters

THE "Great Pacific Garbage Patch" lies off the coast of California. But it is not the only place where a system of rotating ocean currents, known as gyres, concentrate floating material, particularly plastic detritus dumped into the sea or washed out from rivers. There is an awful lot of it: at least 268,940 tonnes, a new report estimates. And there may well be even more, mostly invisible to the eye, because the patches of rubbish appear to work like giant shredders, breaking plastic items down ...