SSS 2009-08-21（在线收听）

The Great Pacific Garbage Patch may be disappearing, and not in a good way. New research presented at the biannual meeting of the American Chemical Society reveals that polystyrene actually can break down in seawater.

Polystyrene is probably better known as Styrofoam, wads of which can be found on seashores and floating out to sea. Most scientists assumed it would linger forever but apparently, when exposed to sunlight and rain and seawater, Styrofoam breaks down into its constituents, most notably three chemicals known to cause cancer.

Japanese chemists found traces of these chemicals in samples of seawater from across the Pacific.

They also found bisphenol A, or BPA, which is another chemical that leaches from some plastics. BPA has been linked to human health impacts, such as heart disease, as well as developmental and reproductive disorders in animals.

Of course, these chemicals are diluted almost beyond detection by the vastness of the sea and not all plastics are exposed to strong sunlight or warm waters. But it’s clear that the millions of tons of plastic pollution building up in the world's oceans are up to no good.