Salmon

This from the University of Wisconsin Sea Grant Institute (February, 2001):

University of Wisconsin scientists have found high levels of a common chemical flame retardant in Lake Michigan salmon, according to a report published today by the science journal Environmental Science and Technology. "The concentrations are among the highest reported in the world for salmon in open waters," said Jon Manchester, co-author of the report and a researcher in the UW-Madison Water Chemistry Program. All 21 of the salmon examined for the study contained chemical compounds called polybrominated diphenyl ethers, or PBDEs, which are chemically similar to PCBs (polychlorinated biphenyls) and dioxins. Like PCBs, PBDEs resist breaking down in the environment and accumulate in animal tissues. Their health risks to humans and wildlife have not been fully assessed, although several studies indicate the risks may be similar to those of PCBs.
    The Lake Michigan salmon, collected in 1996, had an average PBDE concentration of 80 parts per billion. While information on world-wide levels of PBDEs is relatively scant, the levels in Lake Michigan salmon are about six times higher than the levels reported in 1999 for salmon from the Baltic Sea, the world's most-studied area for PBDEs.  The Wisconsin scientists were prompted to look for PBDEs in Lake Michigan salmon after the Wisconsin State Laboratory of Hygiene in 1996 reported finding PBDEs in blood samples from people who ate Lake Michigan fish.
    The PBDE concentrations in the salmon averaged about 6 percent of the PCB concentrations. "Our study did not address how toxic those amounts of PBDEs might be to the salmon," he said. "Those amounts could be more or less toxic than the much higher levels of PCBs we found."  The PBDEs probably have been present in the lake for at least the lifetime of the salmon, or eight to ten years, Manchester said. This preliminary study did not address the concentrations of PBDEs in the lake's water or sediments, he said. Studies of Baltic Sea sediments indicate PBDE concentrations began to accumulate only about 20 years ago, but they are accumulating at a much more rapid rate than PCBs ever did, he said.
    As of the mid-1990s, 50,000 tons of PBDEs were being produced worldwide each year for use as flame retardants in plastics for electronic circuit boards and housings for personal computers and television sets, and in clothing and other textiles. Like PCBs, PBDEs have spread throughout the global environment. PBDEs have been found in sediments, fish, sperm whale blubber, office air, and human blood. A recent Swedish study found a 50-fold increase in PBDEs in women's breast milk during 1972-97. Compared with PCBs, little is known about the possible health effects of PBDE exposure.  The Swedish National Chemicals Inspectorate in 1999 called for a ban on all PBDEs, and the European Union has proposed stringent regulations on the disposal of waste electrical and electronic equipment. (-30-)

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