Assessment of atmospheric metal deposition by moss biomonitoring in a region under the influence of a long standing active aluminium smelter

Abstract

Atmospheric pollutants are deposited onto the landscape as either wet or dry deposition. However, traditional monitoring methods can be expensive; moss biomonitoring offers an efficient and simpler tool to evaluate regional patterns in atmospheric deposition. This study carried out a spatial analysis of metal deposition within a region in northwestern British Columbia dominated by emissions associated with aluminium smelting. In total 61 sites were sampled for the moss Hylocomium splendens. Tissues were analyzed for 13 metals (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd and Pb). The concentrations of four metals, i.e., Al, V, Ni and Pb, were significantly correlated with each other and with modelled sulphur deposition. Moreover, these metals were elevated above background concentrations, suggesting that 30% of study sites (covering and area of 20 km north and 10 km south of the smelter) were impacted by smelter emissions. Tissue concentrations of Mn in Hylocomium splendens should be used cautiously, as results suggested that they did not accurately reflect atmospheric deposition. In addition to the traditional wider-scale surveys, moss biomonitoring can be used to efficiently evaluate regional patterns in atmospheric metal deposition associated with industrial emissions sources.