SEMI-PERMEABLE MEMBRANE DEVICES (SPMDS) FOR MONITORING ORGANIC CONTAMINANTS IN THE OTONABEE RIVER, ONTARIO

Semi-permeable membrane devices (SPMDs) were deployed for 4 weeks (May -June, 1994) at 8 sites in the Otonabee River, Ontario, Canada, and su bsequently extracted for analysis of PCBs and polynuclear aromatic hyd rocarbons (PAHs). The concentrations of PCBs were elevated in the SPMD s deployed in Little Lake at the upstream end of this system which ref lects continuing discharges and in-place PCB contamination in this urb an area. However, at sites downstream from Little Lake, the concentrat ions of PCBs increased with distance downstream; indicating either ano ther point-source of PCBs or spatial variations in the partitioning of these compounds into the dissolved phase. The spatial patterns for PA H contamination were similar to PCBs. At one site in Little Lake, SPMD s were collected at 2, 4 and 6 weeks after deployment and these tempor al:contaminant data are consistent with enhanced uptake of PCBs and so me hydrophobic PAHs as water temperature increased. These data indicat e that SPMDs are useful in situ monitoring devices for determining spa tial trends in the contamination of the aquatic environment, but sever al factors can modify rates of uptake into these devices. Copyright (C ) 1996 Published by Elsevier Science Ltd