Date of Award
Great Lakes Institute for Environmental Research
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This thesis examined spatial and temporal patterns of sediment contamination within the Huron-Erie Corridor which consists of two Areas of Concern, the St. Clair River and the Detroit River. Stratified random sampling designs of surficial sediment samples, both current (2013-2014) and past (1999-2005), were used to evaluate contamination patterns as well as trends observed in time. Chapter 2 focused on Mercury (Hg) concentrations to evaluate a geospatial clustering technique (Getis-Ord) neighbourhood parameter and contrast three different methods for Getis-Ord implementation (fixed distance, inverse distance and user defined matrix procedures). Validation exercises indicated that the fixed distance approach yielded the poorest results and generated inaccurate representations of hot and cold spots within the corridor. The inverse distance and user defined matrix approaches yielded similar validation efficacy, with the user defined matrix generating larger hot zone regions that compared best to previously described spatial patterns described in the literature. Chapter 3 focused on 13 priority contaminants to evaluate spatial and temporal patterns of sediment contamination. Data reduction by principle components analysis revealed 2 major contaminant groups; group 1 chemicals included PCBs, PAHs, transnonachlor, DDE and several metals (Cd, Cr, Cu, Fe, Ni, Pb, Zn) and group 2 chemicals was highlighted by HCB and OCS. Total Hg did not load strongly onto any PCA axis but given its importance as a priority chemical, it was evaluated separately. Spatial patterns were much stronger than temporal patterns, with the latter confounded by sampling resolution differences between survey periods. Group 1 chemicals were enriched primarily in the U.S. jurisdiction of the Detroit River. Group 2 chemicals and Hg were enriched in localized areas in Canadian waters of the St. Clair River, variable locations in Lake St. Clair and in U.S. downstream sections of the Detroit River.
LaFontaine, Joseph, "EVALUATION OF SPATIAL AND TEMPORAL PATTERNS OF PRIORITY CONTAMINANTS IN SEDIMENTS OF THE HURON-ERIE CORRIDOR" (2017). Electronic Theses and Dissertations. 5993.