Total gaseous mercury in Qu´ebec Canada/ in 1998

The main objectives of this paper were to report total gaseous mercury TGM. concentrations at four stations along the St. Lawrence River in 1998 and to give some insights regarding their fate. The TGM network stretches from latitudes 458 N to 508 N. TGM and ozone concentrations used as complementary pollutant. were presented. The median TGM concentrations throughout the network varied from 1.62 to 1.79 ngrm3. Sites close to Montr´eal had larger TGM concentrations. Montr´eal surroundings appeared to be a source of TGM. The TGM concentrations were maximum in wintertime and minimum in summertime throughout the sites. However, the diurnal variations were site specific. St. Anicet and L’Assomption were more variable in terms of large concentrations, whereas Mingan and Villeroy were more variable in terms of low concentrations. Ozone and TGM concentrations were positively correlated at some sites Villeroy, Mingan and St. Anicet. whereas they were not at L’Assomption closest site to Montr´eal.. Local TGM and ozone precursor sources would affect the correlation.