Wet Deposition of Heavy Metals in an Arid City

hi order to investigate characteristics of wet deposition of heavy metals in an arid city, precipitation samples were collected for 16 precipitation events in the arid city of Changji. A total of 16 samples were collected and concentrations of principal heavy metals in the atmosphere were examined by inductively coupled plasma-mass spectrometry (ICP-MS) to discuss levels, variation, and wet deposition fluxes of heavy metals. Among these heavy metals in wet deposition, Fe, Zn, and Cu were found to be the highest. Levels of As, Ni, and Cr ranked second, while Pb, Cd, and Hg were found to be the lowest. The concentrations of heavy metals in wet deposition showed distinct seasonal variations, having high values in winter and low values in other seasons. Besides, in general, concentrations of heavy metals in snow were higher than those in rain. Because the winter was cold and long in Xinjiang, emissions from coal-fired heating were high, which was associated with enhanced concentrations of heavy metals. The order of wet deposition fluxes of heavy metals in the whole year was Fe > Cu, Zn > As, Ni, Cr, Pb > Cd, Hg. Compared to other areas, wet deposition fluxes of heavy metals were low in Changji, which may be due to minimal rainfall in the arid city, having a weak scavenging effect of atmospheric pollutants. In addition, because the level of urbanization and industrialization was not high in Changji, emissions of atmospheric pollutants were low.