CHEMICAL COMPONENT ANALYSIS OF ACID RAIN AND ITS SOURCE ASSESSMENT IN YONGCHUAN, SOUTHWEST CHINA

摘要

A research on acid precipitation and rainwater chemical composition in a town, close to large city, was performed in Yongchuan, southwest China. The precipitation was typically acidic and the volume- weighted mean (VWM) value of pH is 5.04. The VWM equivalent concentration of samples compo- nents followed in order ofSO42', NH4+, Ca2+, Hi C1‘, K", Mg“, Nai N03‘ and P043‘. The ions of S043’, NH4+, Ca3+, H‘‘ and C1‘ in rainwater accounted for 88.7% ofthe total ions and S043‘ is the primary cause of acid rain. NH4+ and Ca2+ were the main neutraliz- ing constituents according to calculated neutraliza- tion factors. The enrichment factor shows that S043‘ and N03‘ mainly originated from anthropogenic ac- tivities. NHE might come from agricultural activities. Cl‘ plausibly came from marine sources. Ca3+, Mg2* and K“‘ could primarily resulted from soil. Signi?- cant correlations (P<0.01) were found among SO42‘, NH4+, NO3'and COD re?ect these ions shared com- mon sources such as coal combustion, industrial dis- charge and evaporation chemical fertilizer. Forest planting, minimizing the discharge of sulfurous pol- lutants, reducing emissions from cars and searching sustainable new energy sources to replace fossil fuels could prevent and limit the spread of acid rain.