Organochlorine compounds and their metabolites in seven Icelandic seabird species - a comparative study

The present study is designed to assess the occurrence of a few organochlorine contaminants and their metabolites in eggs of different marine bird species in Iceland, a country located in the sub-Arctic of the North-Western Atlantic. Previous investigations from e.g. Sweden and The Netherlands have shown some obvious differences in contaminant concentrations, including e.g. hydroxylated polychlorinated biphenyl metabolites (OH-PCBs) in guillemot (Uria aalge) and other bird species. Eggs from seven marine bird species, Arctic tern (Sterna paradisaea), common eider (Somateria mollissima), guillemot, fulmar (Fulmarus glacialis), great black-backed gull (Larus marinus), lesser black-backed gull (Larus fuscus), and great skua (Stercorarius skua), that all breed in Iceland, were collected and analyzed for several persistent organic compounds and their metabolites. The contaminant levels varied between the species investigated. The highest concentrations were found in eggs from the great skua (18 and 23 microg/g l.w. of CB-153 and 4,4'-DDE, respectively). The concentration difference was generally 2 orders of magnitude higher in great skua for all organochlorine compounds analyzed with the exception of HCB. HCB did not vary as much between the seven species (ranging from 34 to 710 ng/g l.w). OH-PCB and MeSO(2)-PCB metabolites congener concentrations and patterns showed differences in metabolic capacity between bird species. Guillemot and great skua seem to distinguish themselves most from other species i.e. with the absence of 4-OH-CB187 and low relative levels of 4-OH-CB146 in guillemot and the low abundance of OH-PCBs in great skua.