Chemicals that inhibit fires are ubiquitous in consumer products ranging from auto interiors to office equipment. Now, a study has shown that these compounds, suspected of disrupting the body's hormonal system, are accumulating rapidly in animals in the Arctic, thousands of kilometers from where they were used.
PCBs and dioxins and other chemicals are known to spread in the environment and accumulate in the Arctic fauna. But the new study, by environmental chemists Michael Ikonomou, Sierra Rayne, and Richard Addison of the Canadian Department of Fisheries and Oceans in Sidney, British Columbia, is the first to measure levels of polybrominated diphenyl ethers (PBDEs), a group whose use is required in many products by strict U.S. safety regulations. In a study that will appear in the 1 May issue of Environmental Science and Technology, the researchers report that in ringed seals--the most common Arctic seal and the main prey of polar bears--PBDE concentrations increased nearly 10-fold between 1980 and 2000. The team also looked at PBDEs in crabs, fish, and porpoises from the coastal waters of British Columbia during the mid-1990s and found that all of the animal samples they tested had statistically significant levels. "The bottom line," Ikonoumou says, "is that no matter where we have looked, PBDEs are there, and the closer you are to industrial and population centers, the higher the levels." For example, he says, harbor porpoises of the British Columbia coast show 400 times higher concentrations than Arctic ringed seals.
PBDEs are strongly suspected to disrupt endocrine system functions and, in particular, to perturb thyroid hormones. Studies of PBDEs in human milk in Sweden prompted officials there to ban the chemicals in 1996. The European Union recently outlawed the most widely used commercial PBDE mixture, but North American manufacturers continue to use tens of thousands of kilograms annually--the exact quantities are industrial secrets.
"This is the first study to demonstrate that levels ... are increasing not just close to centers of use, but in very remote sites, and at similar rates," says Derek Muir of Environment Canada in Burlington, Ontario. Although it's not fully clear how PBDEs make their way from consumer goods to the Arctic food chain, he says, "we can see that these compounds can move quickly."