福州市大气PM_(2.5)中金属与类金属来源解析及健康风险评估

Source apportionment and health risk assessment of metals and metalloids in PM_(2.5)in Fuzhou City

目的研究福州市大气PM_(2.5)中金属与类金属来源及其对人群的致癌和非致癌风险。方法2017—2021年每月采用滤膜采样法在福州市仓山区、台江区收集PM_(2.5),采用称重法测定PM_(2.5)浓度,电感耦合等离子体质谱法监测PM_(2.5)中金属与类金属成分。采用富集因子法和主成分分析方法解析PM_(2.5)中金属与类金属来源,评估PM_(2.5)中金属与类金属成分经呼吸道途径的致癌和非致癌风险。结果福州市仓山区PM_(2.5)中砷、镉、铅、锰中位浓度高于台江区,差异有统计学意义(Z=−3.642、−2.097、3.690、−3.261,P<0.05);两区PM_(2.5)中铝、镉、硒的富集程度较高,富集因子>40,锑的富集程度在10~40,主成分分析显示,主因子1载荷值较高的元素包括镉、砷、锰、硒、铊、铅、锑,主因子2载荷值较高的元素包括铬和镍,主因子3载荷值较高的为铝。2017—2021年福州市仓山区、台江区铬和砷的超额致癌风险值四分位数均在1×10^(−6)~1×10^(−4),具有一定的致癌风险,两区镉元素的超额致癌风险中位值<1×10^(−6),但是P75值致癌风险>1×10^(−6)。结论福州市大气PM_(2.5)中金属与类金属主要来源可能为汽车尾气排放、燃煤、工业排放及扬尘等。大气PM_(2.5)中铬、砷对人群有潜在的致癌风险。

Objective To investigate the sources of metals and metalloids in PM_(2.5) in Fuzhou City and to analyze their carcinogenic and non-carcinogenic risks.Methods Ambient PM_(2.5) samples were collected monthly by membrane filtration method in Cangshan District and Taijiang District in Fuzhou from 2017 to 2021.The concentration of PM_(2.5) was measured by weighing method,and the metal and metalloid components were detected by inductively coupled plasma-mass spectrometry(ICP-MS).The sources of metals and metalloids in ambient PM_(2.5) were analyzed using enrichment factor analysis and principal component analysis.The carcinogenic and non-carcinogenic risks through the respiratory route were assessed according to the technical specification for health risk assessment of ambient air pollution.Results The median concentrations of arsenic(As),cadmium(Cd),lead(Pb),and manganese(Mn)in Cangshan District were higher than those in Taijiang District with statistically significant differences(Z=−3.642,−2.097,3.690,−3.261,P<0.05).In both districts,the enrichment factor of aluminium(Al),Cd,and selenium(Se)in ambient PM_(2.5) were over 40,and the enrichment factor of antimony(Sb)was in the range of 10-40.The principal component analysis showed that the metal/metalloids with high factor loadings for principal component 1 included Cd,As,Mn,Se,thallium(Tl),Pb and Sb,those for principal component 2 included chromium(Cr)and nickel(Ni),and that for principal component 3 was Al.The quartiles of excess cancer risk of Cr and As in the two districts in Fuzhou from 2017 to 2021 were both between 10^(−6) to 10^(−4),showing a certain risk of cancer.The median excess cancer risk of Cd in the two districts was below 1×10^(−6),but the third quartile of excess cancer risk was more than 1×10^(-6).Conclusion The main sources of metals and metalloids in ambient PM_(2.5) in Fuzhou City may be vehicle emissions,coal burning,industrial emissions and dust.Cr and As in ambient PM_(2.5) impose a potential cancer risk.