Analysis on the chemical characteristics of the atmospheric precipitation in Guilin

Precipitation samples are collected and analyzed from January 2009 to December 2010 in the Guilin, Guangxi. The results show that (1)the pH value and the conductivity are 4.83 and 65 μS/cm respectively, the major anions are SO42- and NO3-,the major cations Ca2+ and NH4+ in the rainwater samples of Guilin; (2) major ion content, rainfall and conductivity assumes obvious seasonal variations, and among them the Ca2+ concentration is higher in summer and autumn, lower in spring and winter; (3)rainfall and TDS show good negative correlation,SO42-and NO3-,and Ca2+ and Mg2+ have good positive correlation; (4)in comparing the situations in the year of 2009-2010 to 1994-1995, the ion in the precipitation has increased by 1.16 times and pH increased to some extent, the rain still belongs to acid rain, and the contributing rate of the NO3-in the precipitation forth formation of acid rain in Guilin has obviously enhanced; (5)through continuous monitoring on rainfall of Guilin during 1 to 6, Mar. 2012, it is found that pH, conductivity and precipitation appear good correlation.