为研究天津市春季道路降尘PM25中重金属污染特征及健康风险,于2015年3月22日-5月23日用降尘缸采集天津市主干道、次干道、支路、快速路道路两侧道路降尘样品,利用再悬浮系统将道路降尘中PM2.5悬浮至滤膜上,并用电感耦合等离子体质谱仪(ICP-MS)测定了PM25中7种重金属(Ni、Pb、Cd、As、Mn、Cu和Zn)的质量分数.结果表明:道路降尘PM25中Ni、Pb、Cd、As、Mn、Cu和Zn质量分数平均值分别为37.05、82.50、1.73、25.65、380.18、201.08和736.43 mg/kg;Igeo(地累积指数)显示,Cd属于强污染,Zn和Cu属于中到强污染,Pb属于中度污染,As属于轻度污染,Ni和Mn属于无污染;健康风险评价显示,手-口摄入是道路降尘PM2.5中重金属进入人体的主要途径,儿童的暴露剂量和非致癌风险均高于成人,总非致癌风险次序为As＞Pb＞Mn＞Cu＞Zn＞Cd＞Ni,其中儿童手-口途径As的暴露风险商(HQing)及非致癌总风险(HI)均为1.23,大于限值(1),对儿童存在非致癌风险;其他重金属非致癌总风险均低于限值,对人体无非致癌风险;道路降尘PM2.5中Ni、As和Cd通过呼吸途径对人体均无致癌风险.%In order to investigate the pollution levels and health effects of heavy metals in road dust deposition,road dust deposition samples were collected in four types of roads from March 22nd to May 23rd,2015 in Tianjin City.PM2.5 fractions were gotten by resuspension system and the concentrations of heavy metals were analyzed by ICP-MS.The average concentrations of Ni,Pb,Cd,As,Mn,Cu and Zn in PM2.5 fractions were 37.05,82.50,1.73,25.65,380.18,201.08 and 736.43 mg/kg,respectively.Analysis by the geoaccumulation index suggested that Cd was strongly contaminated,Zn and Cu were moderate to heavily contaminated,Pb was moderately contaminated,As was slight contaminated,Ni and Mn were uncontaminated.Health risk assessment indicated that PM2.5-bound heavy metals were mainly ingested through hand-mouth route.Results suggested that the order of non-carcinogenic risk index of individual heavy metal was As＞Pb＞Mn＞Cu＞Zn＞Cd＞Ni.Children presented higher non-carcinogenic exposure risk than adults.Particular for As,the HQing and HI value for children was 1.23,higher than the acceptable risk value of 1,indicating an unacceptable potential non-carcinogenic risk for children group.However,carcinogenic risk induced by heavy metal exposure was considered acceptable.
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