News Coverage
Bird eggs' chemical levels could predict Bay trouble
Published September 9, 2004
Flame-retardant chemicals were found in San Francisco seabird eggs at higher levels than in wildlife anywhere else in the world, scientists reported Thursday.
The concentrations of the chemicals called PBDEs in tern eggs are the latest evidence of how the substances are becoming pervasive in the environment and rapidly building up in humans and animals around the world. PBDEs have even been found in mothers' milk.
"There is something to worry about here, although it may not be easy to pin down exactly," said Arthur Holden, a member of a team of scientists at the state Department of Toxic Substances Control in Berkeley that did the study.
"These substances are very persistent. They're not going away soon," he added.
PBDEs, or polybrominated diphenyl ethers, are widely used as flame retardants in computers, televisions, furniture, carpets, textiles and appliances.
Animal research links the chemicals to fetal brain development problems, hearing disorders, memory lost and possibly cancer.
California last year became the first state in the nation to approve a phase-out of two types of PBDEs by 2008.
In their three-year study, state researchers found a tern egg along the Bay with the PBDE levels of 63 parts per million, the highest found in any of the many studies on wildlife.
"I think it suggests the Bay is in trouble," Holden said.
Other studies have shown PBDE levels in San Francisco Bay fish and seals, but not as high as in the terns' eggs.
Terns were picked because they feed on fish, live long and make nests near water, making them a good indicator for a marine environment.
Scientists say they don't have a good understanding what the chemicals do to people or animals, or how it got into the environment.
The material has been found in home and office dust. From there, environmentalists think it may spread through the air.
"The study confirms that chemicals accumulate in wildlife and living things," said Bill Walker, vice president of the Environmental Working Group. "The U.S. appears to be a hot spot. The Bay Area is a hot spot, but why is a mystery."
His environmental group last year released a study showing that American women's breast milk has much higher PBDE levels than women's milk in Europe, where the two types of PBDEs are already banned.
The federal EPA has not banned PBDEs, but U.S. manufacturers have agreed voluntarily to stop production of two variations called penta and octa.
Environmentalists also want to ban another type called deca, but manufacturers have resisted, saying that form of the chemical is safe.