A previously unknown contaminant, similar to PCBs and dioxins, and suspected to be of marine origin, has been found in the eggs of Atlantic and Pacific Ocean seabirds. If a marine organism is proven to be the source, it would be the first instance of a naturally produced organohalogen accumulating in the eggs of wild birds.
The research is reported in the Nov. 19 Web edition of Environmental Science & Technology, a peer-reviewed journal of the American Chemical Society, the world's largest scientific society. The article also will appear in the journal's Jan. 1 print edition.
Concentrations of the contaminant were significantly higher in eggs from the Pacific Ocean, as much as 1.5 to 2.5 times higher, according to the article. "In addition," notes one of the study's primary researchers, Dr. Ross Norstrom, Ph.D., of the Canadian Wildlife Service, "storm petrels, which feed on small fish and other organisms that live near the surface of the ocean, had higher levels than diving birds that feed at lower ocean depths." This would suggest, he believes, that the contaminant exists primarily in the surface layer of the ocean.
Generally, scientific thinking is that "all organohalogens that accumulate in wildlife are from industrial sources or other human activities," says Sheryl Tittlemier, principal author of the research article and a Ph.D. candidate at Carleton University in Ottawa, Canada. "The novel organohalogen appears to be a marine phenomenon since it was found in Atlantic and Pacific Ocean seabird eggs, but was absent in herring gull eggs from the freshwater environment of the Great Lakes." The contaminant, whose source is not yet identified, contains high levels of chlorine, bromine and nitrogen, Tittlemier says.
Researchers don't know what effect the contaminant may have on the eggs. "We're planning on doing some toxicological studies to see if the compound has any biological activity," according to Tittlemier.
The study, done by researchers from Carleton University, the Canadian Wildlife Service in British Columbia and Quebec, and the University of Utah in Salt Lake City, examined the eggs of numerous birds, including various species of albatross, auklet, gull, puffin and storm petrel.
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