Christian Krnic

The St. Marys River is listed as an Area of Concern (AOC) in the Great Lakes Water Quality Agreement between Canada and the United States. The river system has been severely impacted by modifications to its hydrology, as well as local industrial and municipal discharges. Remedial Action Plans (RAPs) by the Ontario Ministry of the Environment have been developed since 1988. Anthracene, flourene, pyrene, total polycyclic aromatic hydrocarbons (PAHs), and total polychlorinated biphenyls (PCBs) concentrations at depths of 0-5 cm and 5-10 cm in a small portion of the St. Marys River were analyzed in this study. The contamination data were provided by Environment Canada through the Canada Centre for Inland Waters. Ordinary kriging and inverse distance weighting (IDW) spatial interpolation techniques were used to calculate and compare estimates between sample locations for the contaminants. The results show that the 0-5 cm depth is less contaminated than the 5-10 cm depth. The lower contamination levels in the top layer may signify that historical contamination was greater than present day contamination. Overall, the contamination concentrations are all concerning, as all but two Total PCBs samples are categorized above the Threshold Effect Level (TEL) designated by the Canadian Council of Ministers of the Environment. The two interpolation techniques had similar cross validation statistics however the prediction surface maps produced significantly different patterns in some cases. The findings may assist in restoring the natural habitat of the river and to determine contamination sources.