MEASUREMENTS OF ATMOSPHERIC MERCURY CONCENTRATIONS IN THE CANADIAN ENVIRONMENT NEAR LAKE-ONTARIO

Atmospheric concentrations of total vapor-phase mercury were determined on a daily basis (24-h integrated samples) for a 6-week period (15 March-30 April 1990, inclusive) at Egbert, Ontario, and for 3 consecutive days during the latter part of each of the months of September, October, and November, 1990, at Point Petre, Ontario (site of the first Canadian master research station established under Annex 15 of the Canada-U.S. Great Lakes Water Quality Agreement). All sampling was conducted in duplicate. Gold-amalgamation of vapor-phase mercury species was employed for analyte pre-concentration, clean-up, and analysis steps. Concentrations measured at these sites ranged from 1.3 to 13 ng Hg/m3 (1.4 to 14 x 10(-8) Pa at 0-degrees). Air parcel back trajectories were run for the time periods covered by the environmental measurements and their relationship to the observed atmospheric mercury concentrations are discussed It is shown how data sets of this nature are useful in identifying major are all regional sources of atmospheric mercury emissions. Correlations of observed mercury concentrations with concentrations of other airborne contaminants determined simultaneously were examined and are reported here.