The Welland Canal is the only source of raw water to the largest drinking water treatment plant in the Niagara Region in southern Ontario. The water of the Welland Canal has historically been contaminated from different sources, and identifying these potential pollutants to drinking water relies on direct chemical analysis that is time-consuming and costly to identifying the critical contaminants of concern. Therefore, the aim of this research is to access and prioritize the chemicals of concern and the possible sources of contamination impacting the Welland Canal water. Metals and organic contaminants originating from industrial effluent, agricultural runoff, Port Colborne STP effluent, Lake Erie sediments and antifouling paints on ship vessels are identified as major contributors of pollutant loads into the Welland Canal. Specifically, atrazine, glyphosate, metolachlor, TBT, mercury, lead and zinc are identified as major contaminants that could pose a health risk to over 300,000 residents in the Niagara Region.