赣东北典型重(类)金属污染农田土壤人体健康风险评估

Health Risk Assessment of Typical Heavy Metal(Metalloid)Contaminated Farmland Soils in Part of Northeast Jiangxi

目前关于农田污染土壤直接接触人体的健康风险没有明确的评估规范,部分研究主要采用并不完全适用的建设用地相关参数对农田人群进行健康风险评估,更贴近农田暴露场景相关评估参数的选择仍需进一步探讨。本研究在江西省东北部采集了重(类)金属污染较重表层农田土壤样品,分析了土壤中6种重金属镉、砷、镍、锌、铊和铜的含量,利用我国生态环境部推荐的健康风险评价模型,以农民为暴露对象对该农田土壤进行人体健康风险评价,重点探讨了每日经口摄入土壤量(oral soil ingestion rate, OSIR)、空气中可吸入颗粒物浓度(air inhalable particulate matter concentration, PM10)、每日呼吸空气量(daily air inhalation rate, DAIR)3个参数对评价结果的影响。对比建设用地风险评估推荐参数,更贴近农田暴露场景的上述3个评估参数主要通过增大经口暴露与经呼吸暴露途径的暴露量,显著提升风险水平,其中OSIR和PM10的敏感性比例为100%。单因子砷、镍、镉致癌风险水平超过1.0×10^(-6)的点位占比分别达100%、50%与90%;单因子镉、砷、镍、锌、铊和铜危害商水平超过1的点位占比分别为0%、85%、20%、0%、0%、0%。这些结果表明研究区域农田土壤重(类)金属污染的潜在致癌风险不容忽视,为全面评估农田土壤污染人体健康风险提供参考。

Currently,there are no clear assessment norms about the health risk of direct human exposure to contami-nated soil on farmland.Parameters related to construction land were applied in some studies assessing health risk of farmland populations,which were not exactly applicable.Further exploration is required for the selection of evalua-tion parameters more closely related to farm exposure scenarios.In this study,soil samples from the heavily contami-nated surface farmland in northeastern Jiangxi Province of China were collected and the contents of six heavy metals(metalloid),including cadmium,arsenic,nickel,zinc,thallium and copper in the soil were analyzed.Using the health risk evaluation model recommended by the Ministry of Ecology and Environment of China,human health risk evalu-ation of this farmland soil was conducted with farmers as the exposure target.The impact of three parameters on the evaluation results,namely,daily oral soil ingestion rate(OSIR),air inhalable particulate matter concentration(PM10),and daily air inhalation rate(DAIR),was investigated.Compared with the recommended parameters for risk assess-ment of construction land,the above three assessment parameters,which are closer to the exposure scenario of agri-cultural land,significantly increase the risk level mainly by increasing the exposure through oral and respiratory ex-posure pathways,where the sensitivity ratio of OSIR and PM10 is 100%.The percentages of sites with single-factor arsenic,nickel and cadmium carcinogenic risk levels exceeding 1.0×10^(-6) were 100%,50% and 90%,respectively;while the percentages of sites with single-factor cadmium,arsenic,nickel,zinc,thallium and copper hazard levels ex-ceeding 1 were 0%,85%,20%,0%,0% and 0%,respectively.These results indicate that the potential carcinogenic risk of heavy metal or metal-like contamination of agricultural soils in the study area cannot be ignored,and provide a reference for a comprehensive assessment of the human health risk of agricultural soil contamination.