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 subsequently extracted for analysis of PCBs and polynuclear aromatic hydrocarbons (PAHs). The concentrations of PCBs were elevated in the SPMDs deployed in Little Lake at the upstream end of this system, which reflects continuing discharges and in-place PCB contamination in this urban area. However, at sites downstream from Little Lake, the concentrations of PCBs increased with distance downstream; indicating either another point-source of PCBs or spatial variations in the partitioning of these compounds into the dissolved phase. The spatial patterns for PAH contamination were similar to PCBs. At one site in Little Lake, SPMDs were collected at 2, 4 and 6 weeks after deployment and these temporal contaminant data are consistent with enhanced uptake ofPCBs and some hydrophobic PAHs as water temperature increased. These data indicate that SPMDs are useful in situ monitoring devices for determining spatial trends in the contamination of the aquatic environment, but several factors can modify rates of uptake into these devices.