COMPARISON OF PCB AND TRACE-METAL BIOACCUMULATION IN THE BLUE MUSSEL,MYTILUS-EDULIS, AND THE RIBBED MUSSEL, MODIOLUS-DEMISSUS, IN NEW-BEDFORD HARBOR, MASSACHUSETTS

The accumulation of PCBs and trace metals was compared at 14-d interva ls between two filter-feeding bivales, the blue mussel, Mytilus edulis , and the ribbed mussel, Modiolus demissus, after deployment in New Be dford Harbor, Massachusetts, for up to 56 d. Contaminant uptake in dep loyed organisms also was compared with indigenous ribbed mussels. Sign ificant mortality (> 80%) occurred in blue mussels after 28 d, when wa ter temperatures exceeded 25 degrees C. Therefore, tissue-residue comp arisons between species are presented only up to day 28, while those b etween deployed and indigenous ribbed mussels continue to day 56. Resu lts indicated that total PCB tissue residues and cogener distributions were not statistically different (p > 0.05) in the two mussel species on day 28. Total PCB concentrations in both deployed mussel species r eached approximately 30 mu g g(-1) dry weight by day 28. Additionally, total PCB concentrations and congener distributions in the deployed r ibbed mussels were not statistically different from the indigenous rib bed mussels on day 28, demonstrating that steady state was attained wi thin 28 d. With respect to metal uptake, no signal accumulation patter n occurred for the eight metals quantified. After 28 d, lead, cadmium, and iron concentrations in deployed blue and ribbed mussels were stat istically similar. However, nickel and zinc accumulations were signifi cantly greater in the blue mussels, and copper, chromium, and manganes e were accumulated to significantly higher concentrations in the ribbe d mussels. The comparison between the ribbed mussels indicated that ca dmium and lead concentrations were significantly higher in indigenous than in deployed mussels after 28 d.