【摘要】 为弄清长春市城区大气降水pH值及重金属湿沉降状况,于2006年8月—2007年7月在3个采样点分4季系统收集了大气降水样品12件,采用全谱直读电感耦合等离子体质谱仪(ICP-MS)分析了As、Cd、Cu、Pb、Zn、Cr,采用原子荧光光度法(AFS)分析了Hg。结果表明:长春市大气降水年平均pH值为6.43,总体上为中性雨;降水中重金属质量浓度较低,Hg、Cr、Cu、Zn、As、Pb、Cd分别为0.042、3.59、9.25、148.6、18.44、21.71、0.933μg/L,且受气象条件(如气温、风速、相对湿度等)影响明显,同时随区域的不同而略有差异。总体而言,除Cr外,各重金属元素质量浓度在春冬季明显高于夏秋季,汽车厂附近区域大气降水中重金属质量浓度最低。经估算,As、Cd、Cr、Cu、Hg、Pb和Zn湿沉降通量分别为2.13、0.21、1.70、3.74、0.019、6.826、5.78 mg/(m2.a),且主要集中在3—9月。更多还原

【Abstract】 A series of investigations were performed to show the current situation of pH of precipitation and wet deposition of heavy metal,in Changchun City,China.A total of 12 samples of atmospheric precipitation were collected at three representative sites using bulk deposition sampling method in the periods of 2006-2007(about one year).The heavy metal content were analyzed by atomic fluorescence spectrometry(AFS) and Inductively Coupled Plasma-Mass Spectrometric(ICP-MS).According to the analytical results,the average pH value of the precipitation was 6.43,which was neutral as a whole.The content of Hg,Cr,Cu,Zn,As,Pb and Cd in precipitation in Changchun is generally low with the concentrations of 0.042,3.59,9.25,148.6,18.44,21.71,0.933μg/L respectively.The concentrations of heavy metals were generally higher in the spring and winter period than that in the summer and autumn period,which might be the result of washouting effect in rainy season,meanwhile,the concentrations of heavy metals were generally lower in the area of automobile factory than in the other areas.According to the calculated results,the wet deposition fluxes of As,Cd,Cr,Cu,Hg,Pb and Zn in Changchun were 2.13,0.21,1.70,3.74,0.019,6.82,65.78 mg/(m2·a),respectively.The deposition fluxes of heavy metals were generally higher in the March to September periods than that in the other periods.更多还原