Global assessment of polybrominated diphenyl ethers in farmed and wild salmon.

We have shown recently that levels of persistent, bioaccumulative contaminants (polychlorinated biphenyls, dioxins, and several chlorinated pesticides) are significantly higher in farmed than in wild salmon and that European farm-raised salmon have significantly greater toxic contaminant loads than those raised in North and South America. In this paper, we extend these results to polybrominated diphenyl ethers (PBDEs) and show that farm-raised salmon have higher levels of these compounds than wild salmon. We also show that farm-raised salmon from Europe have higher PBDE levels than those raised in North America and that both European and North American farm-raised salmon have higher PBDE levels than those farm-raised in Chile. Among the species of wild salmon, chinook had significantly elevated PBDE levels relative to the other wild species. These elevated PBDE levels may be related to chinook's feeding behavior and trophic level. Among all of the wild species we studied, chinook tend to feed higher in the food web throughout their adult life and grow to be larger individuals.