Temporal trends of Polybrominated diphenyl ethers (PBDE) and Hexabromocyclododecane (HBCDD) in Swedish Otter (Lutra lutra) and Grey Seals (Halichoerus grypus)

Sammanfattning: Polybrominated diphenyl ethers (PBDE) and hexabromocyclododecane (HBCDD) are brominated flame retardants. These compounds are lipophilic, persistent and have been shown to bioaccumulate. The Baltic grey seal (Halichoerus grypus) and the Eurasian otter (Lutra lutra) are top predators and especially exposed to high levels of lipophilic pollutant in their diet due to biomagnification. In the current study temporal trends for PBDE congeners BDE-47, -99, -100, -153, -154 and HBCDD has been performed for the grey seal (1-3 years) collected along the Swedish east coast between 1980 and 2005 and the Eurasian otter collected in various counties in Sweden between 1991 and 2009. The animals were divided into two groups representing the northern and southern part of Sweden to see if there were any difference between the groups. The PBDE congener profile and pattern as well as if there is any connection between the concentrations and intestinal ulcers in the grey seal was also investigated. There is a significant difference in concentrations for all PBDE congeners between the grey seal in the Baltic Sea (southern group) and the Gulf of Bothnia (northern group), being higher in the northern group. The congener pattern also differs between the groups and seals in the northern area were more characterized by higher brominated congeners. The concentration of HBCDD were increasing in both groups but not for the last ten years of the time trend and the concentrations of the PBDEs were in general decreasing in both groups. High concentration of BDE-99 and HBCDD might be an additional factor contributing to the frequency of intestinal ulcers. The concentration of the sum of PBDEs in the entire otter population was decreasing and this was seen in both the northern and the southern group. The profile of the single PBDEs was similar in both groups but differed from that seen in marine mammals and other studies on otters.