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Tainted Catch: Brominated fire retardants (PBDEs) found in San Francisco Bay fish

Toxic fire retardants are building up rapidly in fish -- and people.

By Sonya Lunder, MPH and Renee Sharp, July 2003

Levels of a little-known class of neurotoxic chemicals found in computers, TV sets, cars and furniture are building up rapidly in key indicator species of San Francisco Bay fish, according to tests by the Environmental Working Group (EWG.)

Analysis of six species of Bay fish, conducted for EWG by a California state toxics lab, detected polybrominated diphenyl ethers (PBDEs) in every fish sampled. The tests compared fish caught by local anglers with archived samples caught in 1997, and found that PBDE levels more than doubled in halibut and more than tripled in striped bass. Striped bass and halibut are the two most commonly eaten species of Bay fish, and as large, mobile, carnivorous species, are good indicators of overall toxic contamination in the Bay.

These are the first findings for PBDEs in Bay fish. They add to the evidence that the Bay Area is a hotspot for exposure to bromine-based chemicals, widely used in commercial flame retardants, that many scientists warn are “the next PCBs” — a notorious class of chemicals banned in 1977 after evidence that they cause cancer and build up in people and the environment. The European Union has banned two of the most commonly used PBDEs, effective next year, but in the United States they remain virtually unregulated by either state or federal authorities.

PBDEs and other brominated fire retardants (BFRs) are similar in chemical structure to PCBs, which are still found in the bodies of people and animals more than 20 years after they were removed from commercial products in the United States. Recent research on animals has shown that exposure to low levels of PBDEs can cause permanent neurological and developmental damage including deficits in learning, memory and hearing, changes in behavior, and delays in sensory-motor development. Most at risk are pregnant women, developing fetuses, infants and young children, and to a lesser extent, the 10 million Americans with hypothyroidism.

Every day, a typical American comes in contact with dozens, if not hundreds, of consumer goods that contain PBDEs, including electronics, electrical cables, carpets, furniture, and textiles. Although the pathway by which PBDEs and other brominated fire retardants get into the environment is largely still a mystery, the chemicals are now found worldwide in house dust, indoor and outdoor air and the water and sediments of rivers, estuaries and oceans. PBDEs have been found in the tissues of whales, seals, birds and bird eggs, moose, reindeer, mussels, eels, and dozens of species of freshwater and marine fish.

Rapid Increases in Humans

PBDEs are also building up rapidly in the bodies of people. Levels in Swedish breast milk samples were 55 times higher in 1997 than in 1972. The few breast milk samples collected from U.S. women indicate even higher levels of PBDEs in the bodies of first-time mothers than found in Europe and Canada. Already, scientists say, most Americans may carry in their bodies levels of PBDEs that have been found to cause serious, permanent neurological damage in laboratory animals.

Though still limited, the data on elevated levels of PBDEs in the Bay Area are disturbing. The levels of PBDEs found in San Francisco Bay fish are much higher than those found in commonly eaten fish species from Europe, Japan, the Pacific Northwest and the Great Lakes. Consumption of contaminated fish is believed to be a major route of PBDE exposure for adults. Earlier studies of PBDEs in the blood and breast tissue of Bay Area women, and of harbor seals from San Francisco Bay, have found levels from three to 60 times higher than levels measured in people and animals in Europe. Ninety-five percent of the type of PBDEs that bioaccumulate most readily is used in North America, and much of that amount goes into polyurethane foam sold in California, but it is unknown exactly why contamination is so high in the Bay Area.

In the fall of 2002, EWG researchers collected 22 fish from six of the most commonly eaten species at 10 locations around San Francisco Bay. Analysis conducted under contract by the state Department of Toxics Substances Control’s Hazardous Materials Laboratory in Berkeley found that every sample contained seven different PBDEs, in concentrations ranging from trace amounts to more than 60 parts per billion (ppb) in fish tissue. We also tested for PBDEs in fish samples archived from 1997, and found that in five years, levels of the chemicals had increased in four of six species tested.

The California Legislature is considering a ban on some types of PBDEs in consumer products by 2008. AB 302 by Assemblywoman Wilma Chan of Alameda, which passed the Assembly in May 2003 and is pending a vote in the state Senate, would make California the first state in the nation to regulate PBDEs. The bill is an important first step, but additional action will be necessary to fully protect public health. Some industries, notably many computer makers, are already moving toward safer alternatives, but the rapid buildup of PBDEs in people, animals and the environment makes it imperative that all brominated flame retardants must be phased out quickly.