Sediment and biological contamination in the Cornwall-Massena section of the St. Lawrence River.

Abstract

The St Lawrence River, near Cornwall, Ontario and Massena, New York, was declared an Area of Concern (AOC) by the International Joint Commission in 1985 due to high levels of contaminants in physical and biological components of the environment. A Remedial Action Plan (RAP) was established to identify specific problems and implement remedial measures. As part of the RAP process, the public at large was consulted and one of the identified concerns was the extent of mercury and PCB contamination of bottom sediments. We assess the evidence for local origin of mercury and PCB sediment contamination by looking at the spatial relationships between suspected point sources and spatial gradients in sediment contaminant levels. The results strongly suggest that the Domtar and Courtauld's outfalls are (were) important local sources of mercury. Similarly, there is strong evidence that the Grass River (ALCOA), Reynold's and G.M. as a group comprise an important local source of PCBs. We examine spatial correlations between mercury and PCB concentrations in sediments and a small nearshore planktivore, the Spottail Shiner (Notropis hudsonius). (Abstract shortened by UMI.)