西安大气PM_(2.5)中金属元素特征及健康风险评价

Characteristics and Health Risk Assessment of PM2.5-bound Metal Elements in Xi’an City

为探究西安市大气PM_(2.5)载带金属元素污染特征及潜在健康风险,作者于2022年3月-2023年2月采集PM_(2.5)有效样品167份,采用电感耦合等离子体质谱仪对12种金属元素进行测定。结果表明,西安市PM_(2.5)年均质量浓度是《环境空气质量标准》(GB 3095-2012)中二级浓度限值的2.01倍。As和Cr(Ⅵ)年均质量浓度分别是一级浓度限值的1.04和14.80倍。富集因子分析结果显示Se和Cd富集程度最高。主成分分析结果显示西安市重金属元素主要来源于燃煤源和交通源、自然源、工业源,贡献率分别为41.24%、21.49%、11.50%。Mn、Pb、As、Cr(Ⅵ)、Sb、Se、Cd、Ni和Hg 9种重金属总非致癌暴露风险值<1。As、Cr(Ⅵ)、Cd和Ni 4种重金属总致癌暴露风险值介于10^(-6)~10^(-4)之间,总体具有潜在致癌风险。成人和儿童As的致癌暴露风险值及成人Cr(Ⅵ)的致癌暴露风险值均介于10^(-6)~10^(-4)之间,具有潜在致癌风险。重度污染时成人Cd的致癌暴露风险值也介于10^(-6)~10^(-4)之间,具有潜在致癌风险。

To explore the pollution characteristics and potential health risks of atmospheric PM_(2.5)-bound metal elements in Xi’an City,an in-situ study was undertaken with 167 effective PM_(2.5) samples being collected during the period of Mar.2022-Feb.2023,and 12 species of metal elements contained in PM_(2.5) determined by inductively coupled plasma mass spectrometry.As a consequence,the study showed that the average annual mass concentration of PM_(2.5) was 2.01 times the 2nd-class concentration limit of the related state standard,while the annual mean mass concentration of As and Cr(Ⅵ)were 1.04 and 14.80 times the 1st-class concentration limit,respectively.According to the enrichment factor analysis,it was showed that Se and Cd were the most abundant elements,and the result of the principal component analysis revealed that heavy metal elements majorly originated from the coal-combustion/transportation source,natural source and industrial source,with their contribution rates of 41.24%,21.49%and 11.50%,respectively.As for potential health risks,total non-carcinogenic exposure risk value of nine heavy metals including Mn,Pb,As,Cr(Ⅵ),Sb,Se,Cd,Ni and Hg,being<1,while the total carcinogenic exposure risk values of As,Cr(Ⅵ),Cd and Ni were between 10^(-6) and 10^(-4),indicating,on the whole,the potential carcinogenic risks were in existence;the carcinogenic exposure risk of As to adults and children and the carcinogenic exposure risk of Cr(Ⅵ)to adults,the risk values both were in the range of 10^(-6)-10^(-4),showing there existed potential carcinogenic risks.Besides,in the case of heavy pollution of atmospheric PM_(2.5),the carcinogenic exposure risk of Cd to adults,the value was also between 10^(-6) and 10^(-4),indicating a potential carcinogenic risk was in existence as well.