Organochlorines in mother and pup pairs in two Arctic seal species: Harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata)

During the lactation period of two Arctic seal species, pairs of females with their respective pups were caught in the ‘West Ice’, a pack ice area in the Greenland Sea north of Jan Mayen. Blubber samples from pairs of harp seals (Phoca groenlandica) and hooded seals (Cystophora cristata) were analysed for 22 CB-congeners (∑CB), five DDT components (∑DDT), four chlor done-related compounds (∑CHL), three HCH isomers (∑HCH) and HCB using capillary GC-ECD in order to study interspecies differences and generation transfer of organochlorine (OC) pollutants. Highest concentrations of these OCs were found in adult hooded seals where average concentrations in blubber were 4.63 μg g−1 ∑ CB, 2.83 μg g−1 ∑ DDT and 0.98 μg g−1 ∑ CHL, representing five, four and two times the concentration found in adult harp seals, respectively. On the other hand, ∑HCH and HCB levels in adult harp seals were higher or the same as in hooded seals. Different food preference is probably the major factor causing the observed interspecies OC level variations. However, species-specific detoxification may also contribute to these results. An efficient generation transfer of OCs was found in both species. However, this transfer seemed to be selective with respect to OC-groups and certain CB congeners. Concentrations of highly chlorinated CB congeners were relatively less present in pups of both species. An increasing transfer barrier in the order: ∑ HCH ≈ HCB < ∑ CHL ≤∑ DDT < ∑CB seems to exist. The generation transfer of OCs demonstrates the importance of lactation as an excretory route of various CB congeners and pesticides in reproductive female seals but, more important, it demonstrates the need for a better understanding of the consequences this transfer might have for the young animals.