Exposure to sublethal concentrations of PCBs 85 EFFECT OF PCBs IN SELECTED METABOLIC ENZYMES IN JUV ENILE AND ADULT SEA BASS ( Dicentrarchus labrax )

The present study quantifies and explains the diffe rences between measured organ-specific polychlorina ted biphenyls (PCBs) accumulation and elimination kinet ics in seabass ( Dicentrarchus labrax) comparing these results with calculations using the generic model O MEGA. Specimens of approximately 250 g were selecte d and fed with food contaminated with PCBs 18, 44, 49 , 52, 101, 105, 118, 138, 180 and 187. The OMEGA model was applied using a measured biomass (re)prod ucti n coefficient and the food ingestion coefficie nt. It produced estimations of total body concentrations w ithin a factor between 1.5 and 7.0 times of the mea sured and it also reproduced the general trend of the PCB concentrations during the experiment. This study allows us to confirm that there is a significant effect of internal distribution of PCBs in the tissues elimi nat on rate constants and consequently in tissues bioaccumulati on factors (BAF). The distribution of PCBs within t he organism was slower than reported before, due to th e bigger body size and the high lipid content of th ese fish. The present study indicates that internal org ans (liver and visceral fat) can act as a contamina nt sink, producing a variation pattern in muscle that differ s from the overall body. This factor is enhanced if the organism has high lipid content.