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Industrial Discharges and Metals

One of thousands of abandoned mine sites in Canada | Photo: Environment CanadaThe effluent discharges from pulp and paper mills, mining, and the petrochemical industry pose a threat to water quality in many parts of Canada.

Pulp mill effluents are complex mixtures of hundreds of compounds that can cause chronic toxicity and endocrine disruption to aquatic organisms. The discharges from mining operations can result in chronic effects of metals, bioaccumulation and sediment contamination. Petrochemical refineries are located on water bodies that provide cooling water and many petrochemical by-products are toxic, hydrophobic and persistent, often contaminating sediments in nearby waters.

Tools and technologies are needed to distinguish the effects of naturally occurring substances and metals from industry-related effects. Environmental effects programs are also needed to monitor the effects of industrial discharges on Canada's water resources.

Water S&T Research

Environment Canada researchers are exploring the sources and fate of mercury and other heavy metals from industrial discharge points and mining waste sites, and are investigating the distribution of these contaminants in air, water and particles. They are examining the processes that control long-term release of toxic metals from mine waste sites and studying the transport of metals to groundwater.

Experts in the geochemistry of mercury and other metals are studying the variations in stable isotopes of mercury in sediment cores and biological samples from sub-Arctic lakes to assist in distinguishing local geological sources from atmospheric deposition.

Environment Canada scientists are determining the relationship between metal and organo-metal (e.g., tributyltin) bioaccumulation and toxicity in invertebrates and the factors controlling metal bioavailability and toxicity. They are also developing methods for identification of metals responsible for sediment toxicity.

Researchers are identifying processes in pulp mills and chemicals in effluents associated with reproductive impairment in fish. They are evaluating the toxicity of petroleum refinery and oil sands effluents and identifying the chemical constituents associated with the effects.

Environment Canada has developed new stable isotopic techniques and is using them to trace the exposure of aquatic organisms to municipal and industrial effluents and to determine the cumulative impact of effluent discharges and low dissolved oxygen on habitat and benthic food webs in rivers.

Researchers are developing a Canadian Water Quality Index to assess cumulative effects of environmental stresses on aquatic ecosystems and applying mesocosm technology to monitor the impacts of industrial effluents on Canadian waters.


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