THE POSSIBLE ROLE OF METABOLISM IN DETERMINING PATTERNS OF PCB CONGENERS IN SPECIES FROM THE DUTCH WADDEN SEA

During a period of 2 years, one group of captive female harbour seals received contaminated fish from the Dutch Wadden Sea, while a second group was given relatively clean fish from the Atlantic Ocean. Concentrations of individual polychlorinated biphenyl (PCB) congeners were measured in fish and seal blood, and occasionally in faeces of seals. The PCB concentrations were significantly lower (P equals 0. 001) in the seals which had received fish from the Atlantic Ocean. On a wet-weight basis, the concentrations of all congeners were lower in seal blood than in fish, but when expressed on a lipid basis, some congeners were biomagnified. According to their degree of biomagnification in seal blood, PCBs could be divided into persistent congeners and less persistent congeners. Additional study results are discussed.