Madison -- University of Wisconsin-Madison scientists have found in Lake Michigan salmon some of the highest levels reported in the world of a common chemical flame retardant.
The report was published today, Feb. 14, by the journal Environmental Science and Technology.
"The concentrations are among the highest reported in the world for salmon in open waters," says Jon Manchester, co-author of the report and a researcher in the UW-Madison Water Chemistry Program. The study was funded by the UW Sea Grant Institute and the American Chemical Society.
All 21 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 worldwide 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, Manchester says.
The Wisconsin scientists were prompted to look for PBDEs in Lake Michigan salmon by a 1996 report by the Wisconsin State Laboratory of Hygiene stating that blood samples from people who ate Lake Michigan fish contained PBDEs.
The concentrations of PBDEs in the salmon were, on average, only about 6 percent as high as the concentrations of PCBs.
"It's important to note that our study did not address how toxic those amounts of PBDEs might be to the salmon," Manchester says. "Those amounts could be more or less toxic than the much higher levels of PCBs we found."
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Contact: John Karl
jkarl@seagrant.wisc.edu
608-263-8621
University of Wisconsin-Madison
13-Feb-2001