Mercury monitoring in the vicinity of coal-fired power plants in Alberta, Canada

Mercury monitoring was conducted at two sites in close proximity to four coal-fired power plants surrounding Lake Wabamun in western Canada. The four coal-fired power plants, located within a 500km2 area, constitute the densest concentration of coal-fired power generation in Canada. Five years of total gaseous mercury (TGM) data were collected at the two sites, Genesee and Meadows. Additionally one year of speciated mercury data were collected at the Genesee site. The data were analyzed in order to characterise the influence of the coal-fired power plants on the regional ambient mercury concentrations. Mean TGM concentrations of 1.57 ng/m3 for Genesee and 1.50 ng/m3 for Meadows were comparable to other Canadian sites. Maximum TGM concentrations of 9.50 ng/m3 and 4.43 ng/m3 were comparable to maxima recorded at Canadian sites influenced by anthropogenic sources. Analysis of the ambient mercury data in conjunction with other parameters, such as wind direction, corresponding NOx and SO2 concentrations, and NOx/ TGM and SO2/ TGM ratios, provided evidence of influence from the coal-fired power plants. Utilization of the AERMOD dispersion model and analysis of electricity production data provided further understanding of the power plants' contribution to the regional ambient mercury concentrations.