荒漠草原金矿周边土壤重金属分布特征及生态风险评价

Distribution Characteristics and Ecological Risk Assessment of Heavy Metals in Soils Around Gold Deposits in Desert Steppe

以锡林郭勒盟苏尼特右旗境内的毕力赫金矿土壤为试材,采用地统计插值法及单因子指数、内梅罗指数、地累积指数和潜在生态风险指数4种重金属污染评价方法,研究了草原区矿产资源开发对周边区域土壤主要重金属元素空间分布的影响,以期为草原金属矿山的土壤修复和环境治理提供参考依据。结果表明:研究区内4种主要重金属均存在累积情况,其中,As元素有6%点位超过国家土壤农用地二级标准,Cu、Hg、Cd元素皆在管控范围;空间分布上,土壤中Cu、Hg、Cd含量值表现为矿区东侧高于西侧,矿区北侧As含量高于南侧;单因子和地累积指数的土壤重金属污染评价为As>Cd>Cu>Hg,潜在生态风险指数为Cd>Hg>As>Cu,区域的综合生态风险评价结果为RI尾矿库南侧(127.35)>RI尾矿库北侧(118.18)>RI排土场(96.26)。研究区生态风险等级以轻微生态风险为主,10.2%区域处于中等生态风险。

Taking Bilihe gold mine soil in Suniteyou Banner of Xilingol league as the test material, geostatistical interpolation method and single factor index, Nemerow index, geo-accumulation index and potential ecological risk index were used to analyze spatial distribution of major heavy metals in the surrounding soil, in order to provide reference for soil remediation and environmental management of grassland metal mines.The results showed that the four main heavy metals in the study area were accumulated.Among them, 6% of as exceeded the national soil agricultural land grade II standard, and Cu, Hg and Cd were under control.In terms of spatial distribution, the contents of Cu, Hg and Cd in the soil were higher in the east of the mining area than in the west, and the content of As in the north of the mining area was higher than that in the south.The soil heavy metal pollution assessment of single factor and geo-accumulation index were As>Cd>Cu>Hg, and the potential ecological risk index was Cd>Hg>As>Cu.The regional comprehensive ecological risk assessment result as follows, the south side of RI tailings pond(127.35) > the north side of RI tailings pond(118.18) > RI dump(96.26).The ecological risk level of the study area was dominated by slight ecological risk, and 10.2% of the area was at medium ecological risk.