Levels of selected individual polychlorinated biphenyls in different tissues of harbour seals ( phoca vitulina) from the Southern coast of Norway

Abstract

Concentrations of individual polychlorinated biphenyls (PCBs) were determined in blubber, liver, kidney and brain tissues of 10 male harbour seals ( Phoca vitulina) of different ages. The animals were found dead or dying on the southern coast of Norway in 1988 during the morbilli virus epizootic. Twenty-three PCB congeners were investigated in all tissues by capillary gas chromatography with electron capture detection and comparison with standards of the respective congeners (IUPAC numbers 28, 52, 74, 99, 101, 105, 110, 114, 118, 128, 138, 141, 149, 153, 156, 157, 170, 180, 183, 187, 194, 206 and 209). In addition, three toxic coplanar congeners (IUPAC numbers 77, 126 and 169) were investigated in the blubber samples. Total PCB (sum of the determined congeners) in kidney (12–60 nmol g −1), liver (12–90 nmol g −1) and blubber (10–79 nmol g −1) were similar on extractable lipid basis, while total PCB in brain lipid was about 1/10 (1·6–12 nmol g −1). The absolute concentrations of the individual congeners in brain lipid correlated poorly with the respective concentrations in each of the other tissues, while the individual congener concentrations in the lipid fractions of kidney, liver and blubber tended to correlate with each other. The relative concentrations of the sum of the most persistent congeners (PCB-99, −128, −138, −153, −170, −180, −187 and −194) correlated in all tissues, and an increase of the relative concentrations of these congeners, most distinct in blubber, with higher carcass weight, was shown. Also, total PCB in blubber correlated with carcass weight. When comparing the relative concentration patterns of individual congeners (per cent of total) in the four tissues, six congeners differed significantly between tissues, and the relative brain concentrations showed most deviation from the other tissues. The concentration of the coplanar PCBs was 1 : 1000–1 : 1000 of the total PCB concentration. The results demonstrate a lower accumulation together with a different concentration pattern in the brain as compared to other tissues.