Local impacts of coal mines and power plants across Canada. I. Thallium inwaters and sediments

A Canada-wide survey was undertaken of sites associated with coal mines and coal-fired electrical generating stations. Several water samples were foun d to contain very high concentrations of thallium, iron and manganese. High thallium concentrations were found in several sites in Eastern Canada, in spite of the greater coal consumption and production in the western and cen tral regions. The data suggest that coal type (rather than quantity) and/or regional geological contributions are responsible for the high Tl concentr ations observed. Our findings, coupled with others around the world, strong ly indicate that TI is an environmental pollutant. In sediments, the observ ed high ratios of Tl/Hg suggest there is an enrichment of TI by at least 25 % when compared to crustal concentration ratios.