Hardly indestructible, plastics begin decomposing in ocean within a year, spreading harmful chemicalsJeremy Hance
August 20, 2009
"Plastics in daily use are generally assumed to be quite stable," said study lead researcher Katsuhiko Saido, Ph.D. a chemist with the College of Pharmacy, Nihon University, Chiba, Japan. "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."
A boy in Japan points out Styrofoam debris from the ocean. Photo by: Katsuhiko Saido.
Plastic pollution is ubiquitous throughout the oceans. Saido, who is from Japan, said that 150,000 tons of plastic debris washes up on Japanese shores alone every year. Floating islands of plastic commonly form in the open ocean. One of these islands, floating between California and Hawaii, is twice the size of Texas.
The chemicals which are released into the water by decomposing plastics include bisphenol A (BPA) and PS oligomer. These chemicals have been shown to disrupt hormone functioning in animals and affect reproductive processes. Three other chemicals were found in the lab when the plastic was broken down: styrene monomer (SM), styrene dimmer (SD), and Styrene trimer (ST). SM is already a proven carcinogen, while both SD and ST may also cause cancer.
The study raises questions as to whether plastics also break down in fresh water.
The findings were announced this week at the 238th National Meeting of the American Chemical Society (ACS) in Washington, D.C.
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