西南典型菜地土壤重金属健康风险和毒性效应

Health risk and toxic effect of heavy metals in soils from typical vegetable planting areas in southwest China

为揭示我国西南典型蔬菜种植区土壤中重金属的污染特征及人体健康风险,选择通海县菜地土壤为研究对象,分析了土壤中Cd、As、Pb、Cr、Ni、Cu和Zn的积累特征,结合体外胃肠模拟法(SBRC)和胃上皮细胞(GES-1)毒性实验评估土壤中重金属生物可给性与人体健康风险,并利用细胞毒性研究验证健康风险.结果表明:菜地土壤中7种重金属仅Cd的平均含量超出农用地土壤污染风险筛选值(GB 15618-2018),且变异系数(72.73%)最大;Cr、Cd和Zn的平均含量超出了云南省土壤背景值;土壤重金属生物可给性差异较大,Cd的生物可给性(35.31%)最高;研究区可能存在由重金属引起的致癌风险,非致癌风险不明显,Cr、As和Ni是致癌风险的主要贡献元素;基于生物可给性的综合非致癌风险(HI)和综合致癌风险(CR)均小于基于总量的评价结果;健康风险的细胞毒性验证实验表明生物可给态重金属暴露后抑制了细胞活性,改变细胞形态,诱发了明显的胃上皮细胞损伤.

To figure out the pollution characteristics of heavy metals in soils from typical vegetable planting areas in Tonghai,southwest China,we collected 151soil samples and measured the concentrations of Cd,As,Pb,Cr,Ni,Cu,and Zn.Besides,the bioaccessibility and cytotoxicity of heavy metals were investigated by in vitro gastrointestinal simulation method(SBRC)combined with the human gastric mucosa cells GES-1model.Our results showed that the Cd level in soils exceeded the risk screening value(0.6mg/kg,6.5<pH≤7.5,GB 15618-2018)with the greatest coefficient of variation being 72.73%.The average content of Cr,Cd,and Zn exceeded the soil background values of Yunnan Province.In addition,the bioaccessibility of heavy metals in soil varied greatly,with Cd being the highest at 35.31%.There may be carcinogenic risk caused by metals in the study area,where Cr,As and Ni were the main contributors to carcinogenic risks.However,the non-carcinogenic risk was not obvious.The comprehensive non-carcinogenic risk(HI)and comprehensive carcinogenic risk(CR)based on bioaccessibility data were both lower than those based on total concentrations.To validate the above-mentioned results,GES-1cells were employed and exposed to all bioaccessible extracts of soils,cell viability significantly decreased(P<0.05),and cell morphology was altered in all groups,indicating bioaccessible extracts of soils could induce gastric epithelial cell damage.