Abstract

 Various state, provincial, and federal agencies responsible for management of Lake Erie have implemented both regional and localized sediment and fish-tissue assessment projects in order to determine levels of contamination. Of particular concern to these agencies is the persistent and bioaccumulative compounds frequently detected at or above levels associated with adverse biological effects. The main objective of the current study is to aggregate bed sediment and fish tissue data for the Basin, from multiple agencies for a period of over 12 years in order to (1) evaluate the spatial patterns for each compound, (2) characterize the extent of contamination relative to biological effects, and (3) examine the co-occurrence of contaminants in sediment and fish tissue. An additional objective is to identify areas where gaps in data or management efforts may require more information to fully assess the overall health of the Basin. Sediment analyses for more than 2,750 sites and fish tissue for more than 4,310 samples have been aggregated into a single database for the purpose of mapping the distribution of contaminants using a Geographic Information System. The location, concentration, and distribution of 20 contaminants representing trace metals, polychlorinated biphenyls (PCBs), organochlorine pesticides, and polycyclic aromatic hydrocarbons (PAHs) were evaluated in relation to their toxicity to aquatic biota using pre-established sediment quality guidelines or fish-tissue guidelines. Metals exceeded aquatic effect levels for sediment more frequently than any other class of compounds. Organochlorines and PAHs exceeded, with more magnitude than trace metals, the aquatic effect levels for sediments in discrete areas. Analysis shows that despite all efforts to manage high levels of sediment contamination, biologically relevant contamination is evident in a large portion of the open Lake. Moreover, despite differences in collection and analysis methods, mercury and PCB's in fish tissue show a spatial co-occurrence with contaminants in sediments.