Plastics in Ocean May Decompose and Release Toxic Chemicals
A new study shows that plastic waste floating in oceans, like those found in the Great Pacific Garbage Patch, may decompose much faster than expected and release toxic substances into the ocean. This comes as a surprise as plastic was believed to be relatively stable, and only threaten marine animals when eaten. Decomposed plastic may cause additional pollution when the potentially toxic bisphenol A (BPA) and PS oligomer is released into ocean.
The study was announced today at the 238th National Meeting of the American Chemical Society (ACS). The researchers found that polystyrene begins decomposition within a year. With the volume of plastic waste so large, the release of toxic compound may disrupt hormones function and reproductive systems in marine animals.
"Plastics in daily use are generally assumed to be quite stable," said study lead researcher Katsuhiko Saido, Ph.D. "We found that plastic in the ocean actually decomposes as it is exposed to the rain and sun and other environmental conditions, giving rise to yet another source of global contamination that will continue into the future."
Other researchers, however, are not convinced by the result. Ocean researcher Charles Moore said that, "Polystyrene is actually heavier than seawater, so before it ever chemically breaks down or degrades, it may be sinking to the bottom." While Moore was not involved in the particular study, he believes the condition at the bottom of the ocean would not cause decomposition.
Even if polystyrene breaks down in some regions of the ocean, pollution expert Joel Baker of the University of Washington questions whether the amount of chemicals released would be significant compared to the vast size of the ocean itself.
Plastic poses the biggest threat to marine animals that confuse garbage with dinner and end up digesting large quantities of polystyrene. Even if polystyrene isn’t decomposing in the water, Moore said it could be breaking down in the digestive tracts of fish and marine mammals.