甘肃陇南锑矿泄露区土壤重金属污染及风险评价

Pollution and risk assessment of heavy metals in soil of antimony mine leakage area in Longnan,Gansu Province

陇南(甘肃)地区锑矿发生尾矿泄露,导致矿区采矿废物蔓延到周边农田土壤,事故发生后,对部分地区进行了紧急土壤清理。在清理过后的土壤(20-40 cm)取样,进行土壤重金属浓度测定,并通过地质累积指数(Igeo),富集因子(EF),潜在风险评价(RI),主成分分析(PCA)和相关性等技术对重金属的污染程度和来源识别进行了评价和分析。结果表明:Sb、Hg、Al、Cu、Ga、Ge和Zn的平均浓度高于甘肃省的背景含量,尤其Sb和Hg是主要污染物。从潜在风险评价指数计算的所有综合污染指数表明土壤受到重金属污染严重(RI>600)。主成分分析和相关性表明,Sb,Hg,Pb和Zn主要来源于人为的矿区活动,Ga和Ge是受自然源和人为活动共同影响,Cu、Al和Ni主要是自然来源。

The tailings leakage occurred in Longnan(Gansu)antimony mine and the mining waste spread to the surrounding farmland soil.After the accident,the soils were urgently cleaned in some areas.The cleaned soil samples(20-40 cm)were collected and the concentrations of heavy metals were identified.The pollution level and the source seeking of heavy metals were evaluated and analyzed by geological accumulation index(Igeo),potential risk assessment(RI),principal component analysis(PCA)and correlation.The results show that the average concentrations of Sb,Hg,Al,Cu,Ga,Ge and Zn are higher than the background concentrations in Gansu Province,with Sb and Hg being the main pollutants.All the comprehensive pollution indexes calculated from the potential risk assessment index showed that the soils were seriously polluted by heavy metals(RI>600).Principal component analysis and correlation show that Sb,Hg,Pb and Zn are mainly from human activities,Ga and Ge are affected by both natural and human activities,and Cu,Al and Ni are mainly from natural sources.