Japanese scientists testing ocean water and sea sand have found widespread contamination with high levels bisphenol A, a chemical used to make plastic that's able to mimic the female hormone estrogen in living things.
Its presence in sea water comes from the breakdown of the plastic trash being dumped into the sea and from the use of the compound in anti-rusting paints applied to the hulls of ships. BPA is man-made and does not occur naturally in the environment.
The researchers took samples at more than 200 sites, mainly on the coasts around North America and Southeast Asia. They detected the chemical along the shorelines of 20 countries and in every batch of water or sand tested.
Worry over BPA water contamination is relatively new, and few standards exist to protect wildlife from becoming overloaded with the chemical or to suggest bathers would be prudent to avoid going to the beach.
But last fall, Environment Canada proposed a maximum concentration of BPA in industrial effluent. The lowest levels detected by the Japanese scientists were already at least six times higher than the limit being considered by Environment Canada, which was based in part on the ability of even trace amounts of the chemical to impair semen quality in fish.
The research results were presented last week in San Francisco at a meeting of the American Chemical Society, and one of the scientists who conducted the sampling says it shows there is widespread decomposition in the environment of the hard type of plastic, known as polycarbonate, made from BPA. Products ranging from lenses on eyeglasses to big, office-style water jugs are made from polycarbonate.
“We were quite surprised to find that polycarbonate plastic biodegrades in the environment,” said one of the researchers, Katsuhiko Saido, a chemist at Nihon University in Japan.
He thought another big source was from a resin, known as epoxy and made partly from BPA, that is commonly applied onto ship hulls to prevent them from rusting out or becoming covered with barnacles. “This new finding clearly demonstrates the instability of epoxy and shows that BPA emissions from epoxy do [contaminate] the ocean,” Dr. Saido said.
A spokesman for the American Chemistry Council, an industry trade group representing BPA manufacturers, was skeptical of the findings, and criticized them for being presented at a scientific conference rather than in a peer reviewed journal.
"Quite a few studies from other researchers have been published with data on BPA in seawater, freshwater and sediment. None of these researchers have reported BPA at levels even remotely close to what is claimed by the Japanese researchers. The extensive data on BPA that has been published indicates that BPA, if found at all, is present in the environment only at very low trace levels," said Steve Hentges, the spokesman.
Mr. Hentges said it is possible that epoxy resins are used on ships. Because the compounds are highly stable and durable, he said it is "unlikely that they will degrade" to form BPA.
Because BPA is able to stick to substances, the highest levels detected were in sand, at a staggering 28,000 times Environment Canada's proposed limit for water.
“What's really astonishing here is the amounts,” said Frederick vom Saal, a biologist at the University of Missouri, who did not participate in the research.
Dr. vom Saal, a major authority on hormones, is worried that people going to the beach could be exposed to BPA and either absorb it through their skin while swimming or from sand. He said it was “a scary finding that the levels in the ocean could already be at levels where you would not want to swim … This is shocking.”
He says regulatory authorities need to enact measures to prevent BPA from getting into the environment from the degradation of products containing it.
