TRACE-METAL CONTAMINATION IN AND ON BALSAM FIR (ABIES-BALSAMEA (L) MILL) FOLIAGE IN SOUTHERN QUEBEC, CANADA

Atmospheric trace metal contamination in and on forest foliage in southern Quebec has been investigated. Washed and unwashed foliage of Balsam fir from seven sampling sites with different elevation were analyzed by NAA. Metal element concentrations in needles were generally well below the suggested levels of potential phytotoxicity, except for Mn. At three rural mountain sampling locations, Mn concentration exceed 600 mu g/g in washed and unwashed needles. The variability of metal concentrations between individual trees at a given site showed the expected element-specific differences, with most CV's < 50%. The variation of metal deposits on needle surfaces (ng/cm(2)) with elevation and sampling site depended on the element concerned. The input of Al, As, Cr, La, Sb, Sc, Sm, and V, accompanying Fe in deposits on the foliage surface, may mainly come from atmospheric deposition in the form of soil dust and air pollution. Wet deposition samples from Roundtop Mountain suggest cloud immersion as a significant trace element deposition pathway in high elevation forest.