ASSESSMENT OF ATMOSPHERIC HEAVY-METALS BY MOSS MONITORING WITH ISOTHECIUM-STOLONIFERUM BRID IN THE FRASER VALLEY, BC, CANADA

The atmospheric heavy metal pollution of the Fraser Valley, B.C., Cana da was assessed in 1993 by analyzing 62 samples of the common woodland moss Isothecium stoloniferum for lead, cadmium, nickel, zinc, chromiu m, and manganese. The latter two metals did no: show a distinct region al distribution, but lead, cadmium, nickel, and zinc showed distinct p attern along a west-east gradient. High values were found in the metro politan Vancouver area, located in the west of the study region. Signi ficantly lower values were recorded for mosses from the eastern more r ural areas of the Fraser Valley. Metal pollutants are likely to be con tained close to their emission sources by alternating south-east, nort h-west winds. Highest values overall were found in the North Shore Mou ntains, adjacent to Vancouver. This was related to higher precipitatio n and short range pollutant transport from the industrialized, heavily populated areas in the floodplain of the Fraser River.