典型废弃锑冶炼厂土壤重金属污染特征、风险评价及来源解析

Pollution Characteristics,Risk Assessment,and Source Analysis of Heavy Metals in Soil from a Typical Abandoned Antimony Smelting Factory

以贵州省晴隆县大厂镇某典型废弃锑冶炼厂区域表层土壤(0~20cm)为例,系统采集了冶炼厂区域内外共14个点位的土壤样品,分析了土壤中Sb、As、Cd、Cr、Pb、Cu、Zn、Ni和V等重金属污染状况、分布特征及潜在生态风险,并对污染来源进行评价与分析.结果表明,该废弃锑冶炼厂表层土壤重金属ω(Sb)、ω(As)、ω(Cd)、ω(Cr)、ω(Pb)、ω(Cu)、ω(Zn)、ω(Ni)和ω(V)的平均值为4.58~15049.33 mg·kg^(-1),除Cr和Ni外,均超过贵州土壤背景值;Sb和As的单因子污染指数为83.61和7.01,属于重度污染,Pb为无污染-轻微污染;土壤重金属综合潜在生态风险表现为,Sb、As和Cd属于严重潜在生态风险水平,其余重金属处于较重或中度潜在生态风险水平;地累积污染指数评价结果表明研究区土壤主要受Sb和As污染,主要呈现偏重度到严重污染等级;RAC法评价结果表明,Sb是该废弃冶炼厂主要防治对象;两种主要污染物Sb和As的浸出毒性、酸溶态、有效态、胃相和肠相生物可利用态含量较高,具有一定的潜在危险性;相关性分析显示,重金属总量与浸出毒性、有效态、酸溶态、可还原态、可氧化态、胃相提取态和肠相提取态存在一定相关性;APCS-MLR模型表明,Sb、As、Zn、Cu和Cd的来源主要为工业源,Cr和V的来源主要为自然源,Pb的来源主要为混合源.

Considering the surface soil(0-20 cm)from a typical abandoned antimony smelting factory area in Dachang Town,Qinglong County,Guizhou Province,as a case study,a total of 14 soil samples were systematically collected from both within and outside the smelting factory area.The analysis focused on the pollution status,distribution characteristics,and potential ecological risks of heavy metals such as Sb,As,Cd,Cr,Pb,Cu,Zn,Ni,and V in the soil.Additionally,an evaluation and analysis of pollution sources were conducted.The results showed that the mean concentrations of heavy metals including ω(Sb),ω(As),ω(Cd),ω(Cr),ω(Pb),ω(Cu),ω(Zn),ω(Ni),andω(V)in the surface soil of the abandoned antimony smelting factory ranged from 4.58 to 15049.33 mg·kg^(-1).With the exception of Cr and Ni,all values exceeded the background values of soils in Guizhou province.The single factor pollution indices of Sb and As were 83.61 and 7.01,respectively,indicating severe contamination.In contrast,Pb fell within the non-polluted to slightly polluted range.The comprehensive potential ecological risk of soil heavy metals was characterized by severe potential ecological risk levels for Sb,As,and Cd,while the remaining heavy metals fell within a range of moderate to substantial potential ecological risk levels.The assessment of the geoaccumulation index revealed that the soil in the study area was primarily contaminated by Sb and As,predominantly exhibiting contamination levels ranging from moderate to severe.The results from the RAC method suggested that Sb was the dominant focus for remediation in this abandoned smelting factory.The two primary pollutants,Sb and As,exhibited elevated levels in leachate toxicity,acid-soluble fraction,available fraction,gastric phase,and intestinal phase in terms of bioavailable content,indicating a certain potential hazard.Further,correlation analysis indicated a certain correlation between the total amount of heavy metals and leachate toxicity,available fraction,acid-soluble fraction,reducible fraction,oxidizable fraction,gastric phase extractable fraction,and intestinal phase extractable fraction.The APCS-MLR model indicated that the sources of Sb,As,Zn,Cu,and Cd were primarily industrial,while the sources of Cr and V were mainly natural,and Pb originated mainly from mixed sources.