城市土壤重金属含量及其对儿童健康风险的初步评价——以四川省宜宾市为例

PRELIMINARY HEALTH RISK ASSESSMENT OF THE EXPOSURE OF CHILDREN TO HEAVY METALS IN URBAN SOILS ——A CASE STUDY OF YIBIN OF SICHUAN PROVINCE

通过对宜宾市主要街道47个土壤样中Pb、As、Zn和Cu含量的调查研究,并利用健康风险评价模型,初步评价了城市土壤中重金属对儿童(6～12岁)的健康风险。Pb、Zn和Cu采用火焰-原子吸收光谱仪测定,As采用氢化物发生-原子荧光光谱测定。结果表明,宜宾市城市土壤中Pb、Zn和Cu含量显著高于四川省土壤背景值,表现出明显的累积效应(p=0.000),As含量显著低于四川省土壤背景值(p=0.02);与四川省土壤基线值相比,土壤中Pb、Zn和Cu含量的超标率分别为36.2%、29.7%和51.1%,As含量尚未超标。城市土壤中Pb、As、Zn和Cu的单危害指数大小(HI)依次为HIAs>HIPb>HICu>HIZn,总危害指数THI为3.46×10-1。单危害指数和总危害指数均低于可接受水平1,未对儿童表现出非致癌危害。土壤中As的总致癌风险TCR为8.72×10-6,在可接受水平内(1×10-6～1×10-4),未对儿童表现出致癌风险。

In order to assess the health risk of heavy metals in urban soils to the children（6～12years old）,the health risks of heavy metals were assessed based on the model of health risk assessment and a total of 47soil samples were collected from street in Yibin City.Pb,Zn and Cu were analyzed by Graphite Furnace Atomic Absorption Spectrometry（GF-AAS）,and As was determined using Hydride Generation Atomic Fluorescence Spectroscopy（HG-AFS）.The results indicated that the accumulation of Pb,Zn and Cu in urban soils was significant（p=0.000）compared to the background values of heavy metals in Sichuan Province.The concentration of As was significantly lower than the background value（p=0.02）.Using baselines value as the criterion of assessment,the 32.6%,29.7%and 51.1%of the samples in urban soils were above the soil baseline values for Pb,Zn and Cu,respectively.None of the soil samples were beyond the soil baseline value for As.For the none-cancer risk,the highest hazard index（HI）of the heavy metals in street soils was As,followed by Pb,Cu and Zn.The total hazard index（THI）was 3.46×10^-1.HI and THI were below the threshold value of 1,which fell in acceptable level.The total cancer risk of As was 8.72× 10^-6,that fell within the range of threshold values（10^-6～10^-4）.The health risk assessment showed heavy metals in urban soils did not have hazard and cancer risk to the children in Yibin.