How do contaminants find their way into drinking water sources?
Some contaminants found in drinking water sources may occur naturally, such as arsenic. The majority of contaminants are the result of human activities and come from industrial discharges, agricultural runoff, sewage treatment plant outflows, nuclear power plants and other sources of pollution. Not only are such contaminants directly discharged into waterways, but they may also find their way into water from aerial deposition and other pathways. These contaminants are not necessarily eliminated when drinking water is treated. Although the province has set standards for 78 contaminants, there are many chemicals in raw water for which no standards have been set, and many that are not even monitored.
