贵州毛石钼矿区土壤及表层沉积物中重金属形态分析及生态风险评价  

Analysis on Speciation and Risk Assessment of Heavy Metals in Soils and Surface Sediments of Maoshi Molybdenum mining Area in Guizhou

作　　者：程俊伟 蔡深文[1] 黄明琴[1] CHENG Junwei;CAI Shenwen;HUANG Mingqin(Zunyi Normal University,Zunyi,Guizhou 563006,China)

机构地区：[1]遵义师范学院,贵州遵义563006

出　　处：《水土保持研究》2021年第1期353-359,共7页Research of Soil and Water Conservation

基　　金：贵州省教育厅青年科技人才成长项目(黔教合KY字[2019]116,黔教合KY字[2019]110);贵州省黔北土壤资源与环境特色重点实验室开放基金(黔教合KY字[2017]010号,KLSREQ2018005)。

摘　　要：为探究稀有金属钼矿区重金属赋存形态及生态风险机制,研究了贵州毛石钼矿区土壤和沉积物中重金属的含量、形态分布及相关性,并利用单因子指数法和内梅罗综合污染指数法进行了污染评价和分析。结果表明:钼矿区周边土壤和沉积物中主要累积污染元素为Mo,Hg和Cu,土壤中含量分别为64.11,1.14,412.76 mg/kg,沉积物中含量分别为281.08,19.55,693.83 mg/kg,远超当地土壤和沉积物背景值。Pb,Cr,Mn,Zn累积水平相对较低,Cd在沉积物中存在局部累积。土壤中,重金属Mo与Cd,Zn呈极显著正相关(p<0.01),其污染可能具有同源性;Mo和Hg主要以残渣态形式存在,生物有效性较低。沉积物中,Mo以可氧化态形式为主,在氧化和碱性条件下容易转化释放,潜在风险提升;Cd和Mn以酸可提取态为主。研究区土壤和沉积物的内梅罗综合污染指数分别高达20.29,167.32,均属于重度污染水平。钼矿区土壤和沉积物中重金属富集特征显著,已经呈现受多种重金属综合污染的严重形势,生态风险极高。The contents,speciation distributions and correlations of heavy metals in the soils and sediments of Maoshi molybdenum mining area in Guizhou were performed in present study to investigate the occurrence characteristic and ecological risk of heavy metals in molybdenum mining areas.The methods of single factor index and Nemerow index were used for evaluation and analysis of metal pollution.The results showed that the main accumulated pollution elements in the soils and sediments around the molybdenum mining area were Mo,Hg,and Cu.The average concentrations of Mo,Hg,and Cu in soils were 64.11 mg/kg,1.14 mg/kg,and 412.76 mg/kg,and in sediments were 281.08 mg/kg,19.55 mg/kg,and 693.83 mg/kg,respectively,which were far beyond the local background values.The accumulation levels of Pb,Cr,Mn,and Zn were relatively low and the Cd accumulated in several sediment samples.Mo was significantly positively correlated with Cd,and Zn in soils(p<0.01),indicating that these metals might come from the same source of pollution.Mo and Hg in soils were mainly in form of residue and had low bioavailability.Mo mainly existed in oxidizable fraction in sediments and easily transformed and released under oxidizing and alkaline conditions.Cd and Mn were mainly in form of acid-soluble extraction.The Nemerow comprehensive indexes of soil and sediment were as high as 20.29 and 167.32,respectively,and both belonged to severe pollution level.The research area was characterized by significant enrichment of heavy metals and have shown a serious situation of comprehensive pollution and extremely high ecological risks.

关 键 词：钼矿区 重金属 分布特征 形态 污染评价 

分 类 号：X833[环境科学与工程—环境工程]