Organochlorine burdens in blood of ringed and bearded seals from north-western Svalbard

Abstract

Ringed seal ( Phoca hispida) and bearded seal ( Erignathus barbatus) are the main prey of polar bears ( Ursus maritimus), and information on organochlorines (OCs) in these pinniped species is important to understand the transport, fate and effects of persistent organic pollutants in the Arctic ecosystem. Thus, OCs were analysed in blood samples of bearded and ringed seals from the coastal ecosystem of the north-western Svalbard archipelago (Kongsfjorden, 78.55°N). The relative contribution of OCs could be ranked as follows: Ringed seal females: ∑PCB>∑DDT>∑CHL>∑HCH>HCB>Mirex. Ringed seal males: ∑PCB⩾∑DDT>∑CHL>∑HCH⩾HCB⩾Mirex. Bearded seal females: ∑PCB>∑HCH⩾∑CHL>∑DDT>Mirex>HCB. Bearded seal males: ∑PCB>∑DDT⩾∑CHL>∑HCH>Mirex⩾HCB. The concentrations of ∑PCB and ∑DDT were higher in ringed seals than in bearded seals, whereas ∑HCH was higher in bearded than in ringed seals. In ringed seal females and males ∑PCB was 337 ± 95 ng/g ( n=6) and 625 ± 443 ng/g ( n=6), whereas ∑DDT was 165 ± 47 ng/g ( n=6) and 621 ± 559 ng/g ( n=6), respectively. In bearded seal females and males, ∑PCB was 159 ± 132 ng/g ( n=6) and 248 ± 93 ng/g ( n=5), whereas ∑DDT was 46 ± 41 ng/g ( n=6) and 161 ± 71 ng/g ( n=5), respectively. The inter-species differences are caused by a higher trophic position of ringed seals in the Svalbard ecosystem compared to bearded seals. OC levels in ringed seals at Svalbard are similar to those reported from the North-American Arctic and in the lower range compared to previously reported data from Svalbard.