河北省农田土壤重金属污染及健康风险评价

目的 分析河北省农田土壤重金属污染现状及健康风险。方法 应用分层随机抽样法，于2014年在全省范围采集2 700份农田土壤样本，检测其中铅、镉、铬含量，运用美国环保局（USEPA）推荐的模型进行健康风险评价。结果 铅、镉、铬平均含量依次为18.52、0.4、39.63 mg/kg；13.74%的样本镉含量超出国家二级标准，铅、铬含量均未超标；重金属通过皮肤接触产生的非致癌风险为1.7×10^-6~8.25×10^-4，大小依次为铬>铅>镉，均低于非致癌风险阈值1；镉、铬致癌风险为4.40×10^-9~4.34×10^-5，在可接受水平内（10^-6~10^-4）；镉造成的成人预期寿命损失为0.03~1.17 min，铬为29.22~269.77 min。结论 河北省部分农田土壤已受到镉污染，重金属经皮肤接触产生的非致癌风险和致癌风险均不会对人体造成健康危害。

Status and health risk assessment of farmland soil heavy metal contamination in Hebei province

Objective To analyze the status and health risk of farmland soil heavy metal contamination in Hebei province.Methods Totally 2 700 farmland soils samples were collected with stratified random sampling in Hebei province in 2014;then contents of lead,cadmium,and chromium in the soil samples were determined.The health risks related to the soil heavy metal contaminations were estimated using health risk assessment model recommended by the United States Environmental Protection Agency.Results The average content of lead,cadmium,and chromium were 18.52,0.4,and 39.63 mg/kg,respectively.The content of cadmium in 13.74% of soil samples exceeded the national secondary standard;while the content of lead and chromium did not exceed the national standard.The range of non-carcinogenic risks related to the soil heavy metal contamination was from 1.7 10^-6 to 8.25 10^-4;the health risks related to the contamination of the three metals decreased in an order of chromium,lead,and cadmium and were all less than the thresholds of 1.The range of carcinogenic risk of cadmium and chromium contamination was from 4.40 10^-9 to 4.34 10^-5,which was within the range of acceptable risk (10^-6-10^-4).The life expectancy loss due to soil cadmium contamination ranged from 0.03 minute to 1.17 minutes and that due to chromium contamination ranged from 29.22 minutes to 269.77 minutes.Conclusion There was farmland soil cadmium contamination but there were neither non-carcinogenic nor carcinogenic health risk related to the skin contact to farmland soil lead,cadmium,and chromium contamination in Hebei province.