基于多属性决策方法的太原市冬季街道尘土中潜在有害元素关键来源解析

Analysis of Critical Source of Potentially Harmful Elements in Urban Road Dust During Winter in Taiyuan Based on Multiple Attribute Decision Making Method

为解析太原市冬季街道尘土中潜在有害元素(PHEs)的关键污染来源,采集了40个街道尘土样本,使用电感耦合等离子体质谱和原子荧光光谱仪测定了尘土中As、Cd、Pb、Ni、Cr、Cu和Zn这7种元素的含量.使用内梅罗综合危害指数法(NIRI)、美国环境保护署推荐的健康风险评估模型分别评价了尘土中PHEs造成的生态和居民健康风险;使用正定矩阵因子分解模型结合主成分分析法分析了尘土中PHEs的来源,并基于此计算了不同来源对尘土PHEs的总含量和PHEs造成风险的贡献程度;使用多属性决策方法(MADM)识别了街道尘土中PHEs的关键来源.结果表明:(1)太原市冬季尘土中ω(As)、ω(Cd)、ω(Pb)、ω(Ni)、ω(Cr)、ω(Cu)和ω(Zn)的平均值分别为17.92、0.32、69.10、30.06、107.74、73.37和268.49 mg·kg^(-1),均超过了太原市土壤中相应元素的背景值,说明尘土中PHEs已经出现富集现象,尘土中PHEs的NIRI平均值为63.86,属于中度风险,处在可控状态;(2)尘土中PHEs造成的致癌和非致癌风险均低于阈值,表明其并未对太原市居民造成严重的健康风险,手口摄入是PHEs造成健康风险最重要的暴露途径,As和Cr是PHEs造成健康风险的主要元素;(3)街道尘土中PHEs的主要来源是自然来源、交通来源和工业排放,3个来源对街道尘土中总PHEs的贡献率依次为35.95%、40.25%和23.82%;(4)尽管工业来源对尘土中PHEs总含量的贡献率最小,但是工业来源排放的PHEs造成的危害较大,MADM的计算结果表明工业来源是太原市冬季街道尘土中PHEs的关键来源.结果表明PHEs关键来源的识别能够准确找出污染毒害最大的来源,为后续污染治理提供重要依据.

In order to analyze the critical sources of potential harmful elements(PHEs)in road dust from Taiyuan during winter,40 road dust samples were collected.The contents of PHEs,including As,Cd,Pb,Ni,Cr,Cu,and Zn,in the road dust samples were measured using inductively coupled plasma mass spectrometry and atomic fluorescence spectrometry.The ecological risks and human health risks posed by dust PHEs were assessed using NIRI and a health risk evaluation model recommended by USEPA,respectively.The sources of dust PHEs were identified by using the combination of principal component analysis and positive matrix factorization(PMF);the total PHE contents and the ecological risks and human health risks posed by PHEs in dust were apportioned to the PHE sources based on the PMF results;subsequently,the critical source of dust PHEs was determined using the multiple attribute decision making method(MADM).The results demonstrated that:(1)the average concentrations of As,Cd,Pb,Ni,Cr,Cu,and Zn were 17.92,0.32,69.10,30.06,107.74,73.37,and 268.49 mg·kg^(-1),respectively,which were higher than the corresponding background values of soil in Taiyuan,indicating that the PHEs had accumulated in road dust;the mean value of NIRI was 63.86,demonstrating that PHEs in dust posed moderate risks,and the dust PHEs pollution was controllable.(2)Human health risk assessment indicated that exposure to PHEs in dust did not pose serious non-carcinogenic or carcinogenic risks.Ingestion was the most important pathway for exposure to PHEs in road dust that damages human health,and As and Cr have been found to pose the most risks among the seven PHEs.(3)The present study found three main sources of PHEs measured in the dust:natural,traffic,and industrial,which accounted for 35.95%,40.25%,and 23.82%of the total concentrations of PHEs,respectively.(4)Industrial emissions contributed the least to the total PHEs contents in dust;however,the PHEs released from industrial sources caused relatively high risks,with the results of MADM indicating that industrial sources were the most critical source for dust PHEs.Our results indicated that the critical source identification of PHEs,which was determined to be the most pernicious source,could provide reference for subsequent pollution source control.