CAGED MUSSELS AND SEMIPERMEABLE-MEMBRANE DEVICES AS INDICATORS OF ORGANIC CONTAMINANT UPTAKE IN DORCHESTER AND DUXBURY BAYS, MASSACHUSETTS

An experiment to measure organic contaminant depuration by the blue mu ssel (Mytilus edulis) was carried out by transplanting mussels in stai nless steel cages from a known contaminated site in Dorchester Bay, Ma ssachusetts to a documented clean site in Duxbury Bay, Massachusetts a pproximately 30 nmi south of the original collection site. A parallel contaminant uptake experiment was performed in which mussels from Duxb ury Bay were collected and deployed in similar cages in Dorchester Bay . The bivalves were collected from each transplant site at set interva ls over a period of 95 days to monitor the rates and selectivity of de puration and uptake, respectively, of polynuclear aromatic hydrocarbon s (PAH), polychlorinated biphenyls (PCB), and chlorinated pesticides. In a related study, semipermeable membrane devices (SPMD: polyethylene bags) containing the lipid material triolein were deployed in Dorches ter Bay and collected at the same frequency as the caged mussels to ev aluate their effectiveness as models for estimating bioconcentration o f target organic contaminants. At the Duxbury site, results suggest th at the caged mussels depurated contaminants within 68 days to levels f ound in native animals at the site. At the Dorchester site, bivalves c oncentrated the contaminants to a level similar to the native M. eduli s. PCB and DDT uptake rates were found to be similar between caged mus sels and SPMDs; PAH uptake by the SPMDs was initially lower than by tr ansplanted bivalves. PCB and PAH assemblages were noticeably different between bivalves and SPMDs deployed at the same site.