沧州市大气降水化学特征分析  

Analysis on Chemical Characteristics of Atmospheric Precipitation in Cangzhou City

作　　者：王剑[1] 徐美[1] 叶霞[1] 刘伟[1] 

机构地区：[1]沧州师范学院化学与环境科学系,河北沧州061001

出　　处：《环境科学与技术》2014年第4期96-102,共7页Environmental Science & Technology

基　　金：国家重点基础研究发展规划(973)项目(2007CB407303)

摘　　要：为了解沧州大气降水化学特征，于2009年4—11月采集了沧州大气降水样品，测定了pH值、电导率和主要离子（Na＋、NH4＋、K＋、Mg2＋、Ca2＋、F-、Cl-、NO3-和SO42）浓度。结果表明，观测期间降水pH值为4．18～7．30，降水量加权平均pH值为5．23，降水酸化频率为34％；电导率值为18．5～245．0斗s，Cm，降水量加权平均电导率值为39．2μS／Cm；降水主要离子加权平均浓度为641．36μcq／L；降水中主要阳离子成分是NH4＋和Ca2＋，降水量加权平均浓度分别为191．06和96．81μeq／L，分别占到阳离子总量的53％和27％；阴离子主要成分足SO42-和NO3-，降水量加权平均浓度分别为175．05和58．19μeq／L，分别占到阳离子总量的63％和21％。降水中[SO42-]／[NO3-]值为3．01，仍属于硫酸型降水，但酸雨类型逐渐由硫酸型向硫酸－硝酸混合型过渡；[NH4＋]/[Ca2＋]值为1．97，NH4＋对降水酸度的中和作用要大于Ca2＋；NH4＋、SO42-和NO3-等二次组分占到降水中主要离子总量的66％，表明：二次污染比较严重。降水离子相关分析表明，SO42-、NO3-、Ca2＋、NH4＋的相火性较好，SO42-和NO3的相关系数为0．732，NH4＋与SO42-（R=0．540）、NO3-（R=0．628）的相关系数分别大于Ca2＋与SO42-（R=0．532）、Nq（R=0．4m）相关系数。气流轨迹分析表明，研究区降水主要受到5类气团影响，不同气团影响下，降水pH值、电导率和离子组成存在差异。A comprehensive investigation of chemical compositions of the atmospheric precipitation in Cangzhou City was carded out during the period from April 2009 to November 2009, in which all samples collected were analyzed for the parameters of pH, electrical conductivity and concentrations of major ions （Na＋, NH4＋, K＋, Mg2＋, Ca2＋, F-, Cl-, NOa-and SO42-）. pH of rainwater collected during the monitoring period varied from 4.18 to 7.30 with a volume-weighted mean of 5. 23, frequency of acid rain being about 34% of the total precipitation during this period. The volume-weighted mean ion concentration of the samples was 641.36 μeq/L, and NH4＋ and Ca2＋ were the main cations in precipitation with the volumeweighted means of 191.06 and 96.81 μeq/L,which accounts for 53% and 27% of the total cations in precipitation respectively. On the other hand, SO42- and NO3- were the main anions in precipitation with the volume-weighted means of 175.05 and 58. 19 μeq/L, accounting for 63% and 21% of the total anions in precipitation respectively. The ratio of SO42- to NOS was 3.01, which indicated precipitation of the city was sulfuric; however the gradual transition from sulfuric to sulfuricnitrous type could be perceived. Ratio of NH4＋ to Ca2＋ was 1.97, which indicated the neutralization effect of NH4＋ was stronger than Ca2＋. Besides, the secondary components such as NH,＋, SO42- and NO3- accounted for 66% of the total anions in precipitation, which implied the secondary pollution was rather serious in Cangzhou. The correlation analysis of chemical compositions in the precipitation showed that the correlation coefficients among SO42-, NO3-, Ca2＊, NIL＋ were relatively high; the correlation coefficient between SO42- and NO3- was 0.732; and the coefficient of cprrelation between NH4＋ and SO42-（R=0.540） was greater than that between Ca2＋ and SO,2-（R=0.532）, meanwhile, the coefficient of correlation between NH3- and NO3-（R=0.628） were higher than that between Ca2＋ and NO3-（R=0.410）. In

关 键 词：大气降水 化学特征 沧州 后向轨迹 

分 类 号：X131.1[环境科学与工程—环境科学]