Study of chemical elements in atmospheric precipitation in South Brazil

The present study investigated the chemical composition of wet and bulk atmospheric precipitation samples in the Candiota region, in South Brazil. The samples were analyzed from January to December 2001 at four different stations located 50 km from the emission source. Bulk and wet precipitation were analyzed for conductivity, pH, alkalinity, Cl−, NO3−, F−, SO42−, Na+, K+, Mg2+, NH4+, Ca2+ and Zn, Ni, Cu, Fe, Al, Mn. The average pH value was 5.4 for the region and wet precipitation samples showed higher acid pH values than those of bulk precipitation did. The major ions in wet and bulk atmospheric precipitation showed high NH4+, Ca2+, SO42−, Na+ and Cl− concentrations. Factor Analysis applied to the studied variables allowed identifying the major sources. For major ions, the study identified association of three groups: Mg, Na, Cl and Ca, related to the origins of soil and sea salts; NH4+, K+, SO42− and NO3−, related to local anthropogenic sources (coal burning, agriculture, biomass burning), and H+ and F−, related to the influence of the coal-fired power plant. As for Ni, Zn, Cu, Mn, Al, and Fe it indicated origin from local anthropogenic activities and from the soil, respectively.