2015-2023年合肥市两城区空气PM_(2.5)中金属元素污染特征及健康风险评估

Concentrations and health risks of metal elements in ambient air PM_(2.5)in two urban districts of Hefei city from 2015 to 2023:analysis of monitoring data

目的分析2015—2023年安徽省合肥市两城区空气细颗粒物(PM_(2.5))中金属元素组分及污染特征,评估金属元素经吸入途径的慢性健康风险。方法2015—2023年连续监测合肥市包河区和瑶海区两监测点空气PM_(2.5)中锑、铝、砷、铍、镉、铬、汞、铅、锰、镍、硒和铊等12种金属元素组分,分析其污染水平及时空特征,并依据国家卫生健康委员会WS/T 777—2021《化学物质环境健康风险评估技术指南》对金属元素经吸入途径对人群产生的慢性健康风险进行评估。结果2015—2023年合肥市两城区共采集有效滤膜1522份,瑶海区铝、硒和锑浓度高于包河区(Z_(铝)=–3.505,P_(铝)<0.001;Z_(硒)=–2.148,P_(硒)=0.032;Z_(锑)=–4.919,P_(锑)<0.001),其余金属元素两城区间差异无统计学意义(P均>0.05)。两城区锑、砷、镉、铅、硒和铊年均浓度均随年份逐渐下降,铝则随年份先下降后上升,季节上各重金属浓度基本为冬季>春季>秋季>夏季。两城区各金属元素非致癌风险(HQ)中位数均<1,其中砷、铍、镉和锰HQ值均>1,存在一定的非致癌风险;砷、铍、镉、铬、铅和镍等6种金属元素均存在致癌风险,其中铍、镉、铅和镍致癌风险(CR)有1%~29%在1×10^(–6)~1×10^(–4)范围,砷和铬CR均100%超过1×10^(–6),包河区砷、铬和瑶海区砷均有1%超过了1×10^(–4),致癌风险较高。结论合肥市两城区空气PM_(2.5)中金属元素污染冬季最高,铝、铅、锰和砷污染水平相对较高,非致癌风险主要风险物为砷和锰,致癌风险主要风险物为砷和铬。

Objective To analyze the concentrations and chronic health risks of metal elements in ambient air particulate matter less than 2.5 microns in aerodynamic diameter(PM_(2.5))in two districts of Hefei city,Anhui province,from 2015 to 2023.Methods Monthly 7-day continuous sampling of ambient air PM_(2.5)was conducted from 2015 to 2023 at two monitoring sites in Baohe district and Yaohai district in Hefei city,and 12 metal elements(including antimony,aluminum,arsenic,beryllium,cadmium,chromium,mercury,lead,manganese,nickel,selenium,and thallium)in PM_(2.5)were measured.The concentrations and spatiotemporal distributions of these elements were analyzed,and the chronic health risks associated with the metal elements via inhalation were assessed according to the National Health Commission′s Technical Guidelines for Environmental Health Risk Assessment of Chemical Substances(WS/T 777–2021).Results A total of 1522 valid filter samples were collected in the two districts of the city during the period.The concentrations of aluminum,selenium,and antimony in the PM_(2.5)samples collected in Yaohai district were higher than those in Baohe district(Z_(aluminum)=–3.505,P_(aluminum)<0.001;Z_(selenium)=–2.148,P_(selenium)=0.032;Z_(antimony)=–4.919,P_(antimony)<0.001),while the differences in the concentrations of other metal elements between the two districts were not significant(P>0.05 for all).The annual average concentrations of antimony,arsenic,cadmium,lead,selenium,and thallium in the two districts gradually decreased over the years,while aluminum first decreased and then increased.Seasonally,the heavy metal concentrations were highest in winter,followed by the concentrations in spring,autumn,and summer.The median hazard quotients(HQ)of non-carcinogenic risk for all metals in both districts were less than 1.However,1%to 9%of the HQ values for arsenic,beryllium,cadmium,and manganese were greater than 1,indicating a certain level of non-carcinogenic risk associated with the metals.Six metal elements,including arsenic,beryllium,cadmium,chromium,lead,and nickel posed carcinogenic risks.Among them,1%to 29%of the carcinogenic risk(CR)values for beryllium,cadmium,lead,and nickel were in the range of 1×10^(–6)to 1×10^(–4).All the CR values for arsenic and chromium exceeded 1×10^(–6),with 1%of the arsenic and chromium in Baohe district and arsenic in Yaohai district exceeding 1×10^(–4),indicating a higher carcinogenic risk.Conclusion The concentrations of metal elements in ambient air PM_(2.5)in the two districts of Hefei city were highest in winter,with relatively higher concentrations of aluminum,lead,manganese,and arsenic.Arsenic and manganese were the main contributors to non-carcinogenic risk,while arsenic and chromium were the main contributors to carcinogenic risk.