淮北煤矿周边土壤重金属生物可给性及人体健康风险

Bioaccessibility and health risk assessment of heavy metals in the soil around Huaibei coal mining area

为了探究煤矿周边农田土壤重金属污染状况以及评估可能对人体带来的健康危害,本研究以安徽省淮北地区3座主要煤矿为研究区,对土壤重金属含量进行分析,并采用体外胃肠模拟方法(PBET),计算土壤中重金属的生物可给性,并以此修正健康风险评价计算方法.结果表明,土壤中重金属含量平均值(mg·kg-1)分别为Cd (0.16)、Cr (11.82)、Cu (12.03)、Ni (21.86)、Pb (55.09)、Zn (41.46),与国内不同类型矿区相比,淮北煤矿区周边土壤重金属含量较低;重金属的生物可给性平均值大小顺序是:胃阶段:Pb (61.69%)>Cu (51.88%)>Cd (43.88%)>Cr (26.48%)>Zn (17.45%)>Ni (14.57%),小肠阶段为:Cr (58.80%)>Cu (55.71%)>Zn (51.40%)>Ni (39.44%)>Pb (7.59%)>Cd (7.32%);由生物可给性校正后,成人和儿童不同重金属非致癌风险暴露量均小于1,说明成人和儿童均不存在非致癌风险,不同种类重金属的致癌风险为:Cr>Cd>Ni,其中,Cr的致癌风险介于10-6—10-4之间,表明Cr对人群有一定的致癌风险,但在可接受的范围内,且儿童的致癌风险高于成人,经手-口无意摄入是土壤重金属最主要的暴露途径.

In order to study heavy metals contamination in the mine soils and evaluate health risks to human,three main coal mines in the Huaibei city were selected as the research areas,and the contents of 6 kinds of heavy metals in the soil were analyzed.The bioaccessibility of heavy metals in soil was calculated by using in vitro gastrointestinal simulation experiment,and the calculation methods of health risk assessment were corrected.The mean concentration(mg·kg-1)of heavy metals in soils were Cd(0.16),Cr(11.82),Cu(12.03),Ni(21.86),Pb(55.09),Zn(41.46),respectively.Compared to other mining area in different style in China,soil heavy metals content around Huaibei coal mining area were relatively low.The bioaccessibility showed Pb(61.69%)>Cu(51.88%)>Cd(43.88%)>Cr(26.48%)>Zn(17.45%)>Ni(14.57%)in stomach,and Cr(58.80%)>Cu(55.71%)>Zn(51.40%)>Ni(39.44%)>Pb(7.59%)>Cd(7.32%)in intestinal phase.Based on bioaccessibility correction,the hazard quotient for both adults and children were below 1,indicating no non-carcinogenic risk.The carcinogenic risk for heavy metals was in a decreasing order:Cr>Cd>Ni.The cancer risk values of Cr for adults and Cr for children stood in the range of acceptable risk(10-6—10-4).Children were in higher carcinogenic risks than adults.The ingestion was the primary pathway to exposure the carcinogenic risk of heavy metals.