体外模拟法在土壤-人途径重金属污染的健康风险评价中的应用

Health Risk Assessment of Soil-oral Exposure of Heavy Metal Contaminated Soil by in vitro Method

目的对某重金属污染区域的土壤经土壤-人途径的健康风险进行评估,从而为相关环境决策提供理论依据。方法采集重金属污染区和对照区农田和路旁土壤,通过体外模拟装置模拟人体消化系统进行消化,分别取胃和小肠阶段反应液样本离心过滤后检测其Cd、Pb、Zn含量并计算其生物可给性;根据重金属生物可给量进行健康风险评价。结果污染区土壤在模拟胃阶段的Cd、Pb、Zn的生物可给性分别为21%～33%,21%～28%,33%～43%;对照区分别为27%,23%,95%。污染区土壤在模拟小肠阶段的Cd、Pb、Zn的生物可给性分别为16%～19%,3.4%～4.9%,14%～8%;对照区分别为11%,2.6%,18%。污染区儿童在模拟胃阶段Cd、Pb、Zn的生物可给量分别为0.04～1.46、3.09～55.53、3.86～39.39μg/d,成人分别为0.01～0.36、0.77～13.88、0.97～9.85μg/d。对照区儿童分别为0.01、0.74、5.64μg/d,成人分别为0.00、0.19、1.41μg/d。污染区儿童在模拟小肠阶段Cd、Pb、Zn的生物可给量分别为0.03～0.71、0.50～9.92、1.26～9.55μg/d,成人分别为0.01～0.18、0.11～2.48、0.31～2.39μg/d;对照区儿童分别为0.00、0.08、1.07μg/d,成人分别为0.00、0.02、0.27μg/d。结论污染区V2土壤中Pb对当地儿童的健康具有较大的潜在风险,其他数据虽然在相应限量以下,但由于通过土壤-人途径的摄入会增加人体对重金属摄入的总量,从而使健康风险的总量增加。

Objective To assess the health risk of soil-mouth exposure of soil heavy metal pollution by in vitro method. Methods Collected the soil sampling from the heavy metals contaminated field and roadside. Digested the soil sample by in vitro device and determined the content of Cd, Pb, Zn in the solution in the simulated stomach phase and intestine phase respectively with ICP-MS after centrifuging. Calculated the exposure and assess health risk. Results Bioaccessibility of Cd, Pb and Zn at the stomach phase was 21%-33%, 2%-28%, 33%-43% respectively in the polluted areas, and 27%, 23%, 95% in the control area; At the intestine phase was 16%-19%, 3.4%-4.9%, 8%-14% in polluted areas and 11%,2.6%,18% in control area respectively. The amount of available Cd, Pb and Zn in the stomach phase was 0.04-1.46 μg/d, 3.09-5.53 μg/d, 3.86-9.39 μg/d in polluted areas and 0.01 μg/d, 0.74 μg/d ,5.64 μg/d in control area for children, and 0.01-0.36 μg/d, 0.77-3.88 μg/d, 0.97-9.85 μg/d in polluted areas and 0.00 μg/d. 0.19 μg/d, 1.41 μg/d in the control area for adult ; at intestine phase the amount of available Cd, Pb and Zn was 0.03-0.71 μg/d, 0.50-9.92 μg/d, 1.26-9.55 μg/d in polluted areas and 0.00 μg/d, 0.08 μg/d, 1.07 μg/d in the control area respectively for children, 0.01-0.18 μg/d, 0.11-2.48 μg/d, 0.31-2.39 μg/d in the polluted areas and 0.00 μg/d,0.02μg/d,0.27 μg/d in the control area respectively for adult. Conclusion Heavy metals exposure through soil-mouth pathway will increase the total health risk of heavy metal to exposed population.