PCB ACCUMULATION AND ALTERATIONS OF LIPIDS IN 2 LENGTH CLASSES OF THEOYSTER CRASSOSTREA-ANGULATA AND OF THE CLAM RUDITAPES-DECUSSATUS

Polychlorinated biphenyls (PCB) were analysed in two length classes of the oyster Crassostrea angulata and the clam Ruditapes decussatus col lected in Sado estuary and Ria Formosa, respectively. Oysters showed n o significant differences (p<0.05) in accumulation with size, while sm aller clams presented higher PCB levels than the larger ones. The PCB accumulation in same size classes of the two species, and the effect o f PCB-exposure on their lipids were investigated during 60 d under lab oratory controlled conditions. Again, no significant differences (p<0. 05) in accumulation with relation to size were observed for oysters, w hile smaller clams showed PCB levels 10 times higher than the larger o nes. Triglycerides in the oysters of both sizes displayed a sharp redu ction in the first 30 d of contamination, remaining at very low levels until the end of the experiment. PCB in the larger clams reached 360 ng g(-1) and no change on lipid composition was recorded but in smalle r individuals levels went up to 2400 ng g(-1) and the lipids were alte red. Field and laboratory results showed that small and large individu als of the two bivalve species responded differently in terms of PCB a ccumulation and, under drastic contamination, lipids of oysters were s trongly affected and lipid composition of smaller clams was modified. (C) 1998 Elsevier Science Ltd. All rights reserved.