化工地块污染土壤中砷的生物有效性研究

Bioavailability of Arsenic in Contaminated Soil of in a Chemical Industry Site

生物有效态重金属通过土壤进入人体的途径是工业地块人体健康风险评估较少关注的内容,有效态重金属含量的准确性影响了人体健康风险评估结果的可靠性。以某典型的化工地块为例,采集不同污染程度的土壤样品,采用Tessier顺序提取方法测定土壤不同形态砷含量和砷的生物活性系数,采用In Vitro胃肠模拟实验计算砷在胃和小肠阶段的生物有效性,对比开展砷的生物有效性研究。结果表明,土壤样品中残渣态砷含量占比最高,而有效态砷含量占比较低,生物活性系数为0.0024~0.0210;胃和小肠阶段吸收的有效态砷含量与土壤砷含量呈线性正相关关系,砷的生物有效性为0.78%~36.81%;Tessier顺序提取法得到的有效态砷含量与In Vitro方法相比是偏低的。建议在进行重金属污染土壤的人体健康风险评估时,针对性地开展消化系统模拟实验,得到较为可靠的有效态重金属含量数据。

The way of bioavailable heavy metals entering human body through soil is less concerned in human health risk assessment of industrial sites.The accuracy of bioavailable heavy metal content affects the reliability of human health risk assessment results.Taking a typical chemical industry site as an example,soil samples with different pollution levels were collected.Tessier sequential extraction method was used to determine the content of different forms of arsenic in soil and the biological activity coefficient of arsenic.In Vitro gastrointestinal simulation experiment was used to calculate the bioavailability of arsenic in the stomach and small intestine,and the bioavailability of arsenic was compared.The results showed that the content of residual arsenic in soil samples was the highest,while the content of available arsenic was relatively low,and the biological activity coefficient was 0.0024~0.0210.There was a linear positive correlation between the available arsenic content absorbed in the stomach and small intestine and the arsenic content in the soil.The bioavailability of arsenic was 0.78%~36.81%.The available arsenic content obtained by the Tessier sequential extraction method was lower than that obtained by the In Vitro method.It is suggested that in the human health risk assessment of heavy metal contaminated soil,the digestive system simulation experiment should be carried out to obtain more reliable data of available heavy metal content.