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

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(〖WTBX〗p〖WTBZ〗=0000)，As含量显著低于四川省土壤背景值(〖WTBX〗p〖WTBZ〗=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(〖WTBX〗HI)依次为HIAs>HIPb>HICu>HIZn，总危害指数THI〖WTBZ〗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〖WTBX〗TCR〖WTBZ〗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。

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

In order to assess the health risk of heavy metals in urban soils to the children (6~12 years old),the health risks of heavy metals were assessed based on the model of health risk assessment and a total of 47 soil 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 (〖WTBX〗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 〖WTBX〗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.