Monitoring the distribution and deposition of trace elements associated with a zinc-lead smelter in the Trail area, British Columbia, Canada

The atmospheric deposition and regional dispersion pattern of the elements As, Cd, Cu, Hg, Pb and Zn, emitted from Pb-Zn smelters at Trail, British Co lumbia, Canada, were studied for a period of two years using the passive co llection moss-monitoring method. Concentrations of these elements in moss b ags, exposed to atmospheric deposition for three months, were first correct ed for geogenic input and then site-specific local background level to prod uce common background elemental concentrations for all monitoring stations. The results of this study indicate that the deposition of these elements i s greatest in proximity to the smelter and decreases with an increase in di stance. The regional dispersion pattern generally varies seasonally, with t he magnitude of variation being dependent on the element under study and th e location of the monitoring station. Overall, the deposition of these elem ents (as registered by moss-monitoring stations) appears to be a complex ph enomenon involving various factors such as meteorological conditions (preva iling wind direction and precipitation). physiography (topography. valley s hape and orientation) and in-process activities at the smelters (production level, emission control efficiency and the geochemistry of feed). However, the results of this study indicate that, on an annual basis, in-process ac tivities, particularly production levels of Pb and Zn and the quantity of e missions from the stack, are more directly related to the observed depositi on of the elements than any of the other factors.