Accumulation of organochlorine pesticides and PCBs by semipermeable membrane devices and Mytilus edulis in New Bedford Harbor

We deployed semipermeable membrane devices (SPMDs) and transplanted blue mussels (Mytilus edulis) side-by-side at five sites in New Bedford Harbor, MA. A good correlation was obtained between accumulation in the SPMDs and the caged mussels, with r(2) values ranging from 0.57 to 0.85 for individual pesticides (n = 16) and from 0.81 to 0.96 for individual PCB congeners (n = 20). An excellent correlation also was found between the log K-ow and the log BAF (bioaccumulation factor in mussels) and between the log K-ow and log AF (accumulation factor in SPMDs). Accumulation in the mussels was approximately 2-fold higher than in the SPMDs when concentrations were expressed on a lipid basis. These correlations are significantly better than any reported previously and probably result from modifications that we made to the original design of the SPMD. A close examination of accumulation into SPMDs demonstrates that the uptake rate and equilibrium status of an SPMD can be easily manipulated by modifying membrane thickness, surface area, and lipid substrate volume. Knowledge of these parameters and their effect on SPMD uptake rates is critical to the interpretation of SPMD data and can be used to optimize the design of SPMDs for specific applications.