内蒙古某矿区土壤中砷的分布及赋存形态研究

Study on the Distribution and Occurrence State of Arsenic in Mine Soil,Inner Mongolia

本文以内蒙古某矿区土壤环境为研究对象,利用Ag-DDC比色法测定了研究区不同位置土壤中砷的含量,分析了该矿区土壤砷的分布特征;采用化学逐级提取法对土壤中砷的赋存形态进行了研究。结果表明:研究区土壤样品中总砷含量平均值为8.35mg/kg,低于国家二级标准,但土壤中砷含量及分布与煤矿开采密切相关;开采高砷煤矿,其周边土壤中的砷含量会相应增加;土壤中各形态砷含量存在差异,所占比例依次为:残渣态砷(62.79%)>钙型砷(15.74%)>铁型砷(12.47%)>铝型砷(7.17%)>交换态砷(1.56%)>水溶态砷(0.27%);且非有效态砷含量(62.79%)要高于有效态砷(37.21%)。

The colorimetric analysis of Ag-DDC was used to determine the content of As in soils from different positions, which were sampled from the mining area, Inner Mongolia. The distribution features of As in mine soil were analyzed and the chemi- cal sequential extraction method was used to investigate the occurrence state of As. The results showed that the average content of total As in the soil samples is 8.35 mg/kg, which is lower than the national level 2 standard. But the content and distribu- tion of arsenic in soil are ciosely related to the development of mining area. During high-As coal mining, it was found that the content of arsenic in soil around the mine was increased. The content of arsenic varied with the occurrence state of As. The re- sults showed that As content varied from high to low in the order of residue-state arsenic（62.79%） , calcium-type arsenic （15.74%） , iron-type arsenic （12.47%）, aluminum-type arsenic （7. 17%）, exchanged arsenic （1.56%） and dissolved arsenic （0. 27%） and the content of nomavailable arsenic （62.79%） was higher than that of available arsenic （37.21%）.