Polybrominated diphenyl ethers and selected organochlorine chemicals in grey seals (<i>Halichoerus grypus</i>) in the North Sea

Blubber samples from grey seal (Halichoerus grypus) pups were collected in 1998 through to 2000. Twenty four newly weaned pups were sampled in November 1998, 13 of which were re-sampled during their first year of life, between March and December 1999, and an additional 48 and 25 samples (new cohorts) were obtained in 1999 (November–December) and 2000 (May–September) respectively. ∑PBDE concentrations (sum of Di-HxBDEs) ranged from 45 to 1500 ng/g lipid, with a geometric mean of 290 ng/g lipid. BDE 47 dominated the congener profile, followed by BDEs 100, 99, 153 and 154. ∑PCB concentrations (sum of 41 congeners) ranged from 100 to 93 000 ng/g lipid, with a geometric mean of 4600 ng/g lipid, with CB congeners 153, 138 and 180 making up 84% of the total PCB concentrations. The predominant OC pesticides were p,p′-DDE (geometric mean = 860 ng/g lipid, range = 160–3800 ng/g lipid) and p,p′-DDT (geometric mean = 120 ng/g lipid, range = 30–670 ng/g lipid). No significant differences were found between males and females, probably due to the young age of the animals. Significant decreases (P < 0.01 for PBDEs and P < 0.05 for PCBs/OCs) were observed between newly weaned seals in 1998 and 1999, but not for the majority of juveniles in 1999 and 2000. Significant differences (P < 0.01) were also found between the different seasons in 1999 newly weaned and juvenile seals, reflecting changes in blubber mass.