土壤重金属空间特征及潜在生态风险评价——以西南某典型毒重石成矿区为例

Spatial characteristics and potential ecological risk assessment of heavy metals in soil——A typical toxic and heavy stone metallogenic area in southwest China was taken as an example

为了解在典型毒重石成矿区的土壤重金属空间特征、展布规律及污染状况,在成矿区内及周边采集土壤表层样267件,分别测试pH和Cd、Hg、Pb、Cr、As、Ni、Zn、Cu这8种重金属含量。采用单因子污染指数法、地累积指数法和潜在生态危害指数法,评估该区土壤重金属空间规律及潜在生态风险。结果表明,调查区内除了Pb外,其余重金属平均值都高于重庆市土壤背景值,呈现不同程度的积累;单因子污染指数评价结果表明,Cd元素属于中—重度污染,其余Cr、Pb、Hg、Cu、Ni、Zn、As属于清洁土。地累积指数评价结果表明,土壤中Cd污染较严重,处于中污染状态,Cu、Ni、Zn、As、Hg总体呈轻污染,Cr和Pb无污染。潜在生态风险评价结果显示,毒重石成矿区的主要危害元素指示为镉(Cd)元素和汞(Hg)元素。其中,Hg的生态风险级以中等到强为主;Cd的生态风险级呈中等、强、很强、极强。

In order to understand the spatial characteristics,distribution rules and pollution status of soil heavy metals in typical toxic-heavy stone metallogenic areas,267 soil surface samples were collected in and around the metallogenic areas,and the pH value and the content of 8 heavy metals including Cd,Hg,Pb,Cr,As,Ni,Zn and Cu were tested respectively.The spatial law and potential ecological risk of heavy metals in soil were evaluated by single factor pollution index,land accumulation index and potential ecological hazard index.The results of the the average value of other heavy metals in the survey area was higher than the background value of soil in chongqing except Pb,showing different degree of accumulation.The result of single factor pollution index evaluation shows that Cd belongs to medium to heavy pollution,and the rest Cr,Pb,Hg,Cu,Ni,Zn and As belong to clean soil.The evaluation results of geocumulative index show that Cd pollution in the soil is serious,in the state of medium pollution,Cu,Ni,Zn,As,Hg are generally light pollution,Cr and Pb no pollution.According to the assessment results of potential ecological risk,Cd and Hg are the main ecological hazard elements.Hg is mainly m edium to strong risk,while Cd is mainly medium,strong,high,extrmely ecological risk.