SAN FRANCISCO, March 23, 2010 — Scientists today reported widespread global contamination of sea sand and sea water with the endocrine disruptor bisphenol A (BPA) and said that the BPA probably originated from a surprising source: Hard plastic trash discarded in the oceans and the epoxy plastic paint used to seal the hulls of ships.

"We were quite surprised to find that polycarbonate plastic biodegrades in the environment," said Katsuhiko Saido, Ph.D. He reported on the discovery today at the 239th National Meeting of the American Chemical Society, being held here.

Saido and Hideto Sato, Ph.D., and colleagues are with Nihon University, Chiba, Japan. "Polycarbonates are very hard plastics, so hard they are used to make screwdriver handles, shatter-proof eyeglass lenses, and other very durable products. This finding challenges the wide public belief that hard plastics remain unchanged in the environment for decades or centuries. Biodegradation, of course, releases BPA to the environment."

The team analyzed sand and seawater from more than 200 sites in 20 countries, mainly in Southeast Asia and North America. All contained what Saido described as a "significant" amount of BPA, ranging from 0.01 parts per million (ppm) to 50 ppm. They concluded that polycarbonates and epoxy resin coatings and paints were the main source.

In research reported at the ACS’s August 2009 National Meeting, Saido and colleagues first busted the myth of the everlasting quality of plastics. They revealed that light, white-foamed plastic decomposed rapidly at temperatures commonly found in the oceans. In decomposing, that plastic releases potentially toxic substances. In the new report, Saido’s group now has added hard plastics and hard epoxy resins –– to the plastics that decompose under conditions commonly found in the oceans. Millions of gallons of epoxy resins are used each year to seal the hulls of ships, protecting them from rust and fouling with barnacles and other deposits.

“When epoxy resin breaks down, it releases BPA, a typical endocrine disruptor,” Saido explained. “This new finding clearly demonstrates the instability of epoxy, and shows that BPA emissions from epoxy do reach the ocean. Recent studies have shown that molluscs, crustaceans and amphibians could be affected by BPA, even in low concentrations.” (...)

Here, leaching plastics may not be the primary source of the newfound global marine contaminant

SAN FRANCISCO Chemists have been showing for years that bisphenol A, an estrogen-mimicking building block of polycarbonate plastics and food-can coatings, can leach into food and drinks. But other materials contain BPA – and leach it – such as certain resins used in nautical paint. And Katsuhiko Saido suspects those paints explain the high concentrations of BPA that his team has just found in beach sand and coastal seawater around the world.

Saido, a chemist at Nihon University’s College of Pharmacy, in Chiba, Japan, reported his findings here, today, at the American Chemical Society’s spring national meeting.

At the last ACS national meeting, Saido showed that Styrofoam and related polystyrene-based materials can degrade in seawater and taint the coastal environment with styrene, a toxic building block of the foams. When he announced his styrene findings last September, reporters asked him: What about BPA? Does this potentially toxic breakdown product of the widely used plastics also show up at the beach?

He hadn’t a clue. So he went back and reanalyzed samples of seawater and sand that he had collected for the polystyrene study. And sure enough, BPA was there. Sometimes in fairly substantial quantities, he now reports. Of the 28 sites sampled, he found BPA at all, often at values in seawater at or near 100 parts per billion in Puerto Rico, Guam, Japan, Korea, Taiwan and the Philippines. Concentrations of BPA were orders of magnitude higher in sand. For instance, they exceeded 50 parts per million on a French beach and ranged closer to 100 ppm on sandy shores in Eurasia, Florida and Costa Rica. (...)