Though they are not being used to fight fires in the region, flame retardants are nevertheless quickly contaminating the Canadian Arctic, a new study indicates. According to a report published in the current issue of the journal Environmental Science and Technology, arctic concentrations of chemicals known as polybrominated diphenyl ethers (PBDEs), which are commonly used as fire retardants, have increased exponentially in the past two decades. And if the current rates of accumulation continue, PBDEs could soon surpass polychlorinated biphenyls (PCBs)similar chemicals that are notorious for accumulating in the food chainas the most prevalent organohalogen compound in the Arctic environment.

In order to gauge the environmental fate of PBDEs, Michael G. Ikonomou and his colleagues in the Department of Fisheries and Oceans Canada analyzed the concentrations of the chemicals in the blubber of Arctic ringed seals caught between 1981 and 2000 in the Northwest Territories of Canada. The scientists found that amounts of 13 PBDE variants, or congeners, present in male seals less than 15 years old has increased nearly ten-fold since 1981. Females had lower levels of the chemicals than did males, the team found, which suggests that they pass the compounds to their offspring through their milk.

Until the mid-1990s, the levels of PBDEs in the Arctic seals were higher than those recorded in humans in a Swedish study, suggesting the atmospheric transport of the chemicals from their source to remote regions is very efficient. The levels of PBDEs in the seals also correlate with the worldwide production of penta-DBE, one of three commercial mixtures of PBDEs. Though PBDE levels in humans living near Stockholm declined after Europe placed restrictions on penta-DBE in 1996, levels in the Arctic animals continued to increase. The researchers thus propose that the compounds are reaching the arctic from sources in North America. If the production and utilization of PBDEs continues unabated, the authors conclude, they will surpass the level of PCBs (which are now heavily regulated) by 2050.