德阳石亭江流域马尾河支流某段农田土壤重金属赋存形态特征及潜在生态风险评估

以石亭江流域马尾河支流某段农田土壤为研究对象,通过采集区内的36个土壤样品,测定了土壤中重金属含量及分析了赋存形态,并在此开展了生态风险评价。结果表明,研究区土壤重金属主要以Cd污染为主,超标倍数及污染程度较重;对研究区主要特征污染物Cd进行了Tessier五步连续提取,土壤中Cd主要以残渣态、铁锰氧化物结合和可交换态存在,且重金属Cd主要以难利用态为主,其次为可利用态;基于潜在生态风险指数法和风险编码法(RAC)对土壤中重金属Cd的生态风险进行评价,其Cd污染的潜在生态风险较强。在上述研究基础上,基于Arcgis10.0软件和潜在生态风险指数法对研究重金属的潜在生态风险进行了评价,研究区东北与东南侧区块内土壤重金属Cd潜在生态风险较研究区的其他区域高。

Taking the farmland soil of a section of Mawei River tributary in Shiting River Basin as the research object,36 soil samples were collected to determine the content and form of heavy metals in the soil,and the ecological risk assessment was carried out.The results showed that Cd was the main heavy metal pollution in the study area,which exceeded the standard and the pollution degree was serious.The main characteristic contaminant Cd in the study area was extracted by Tessier five-step extraction.Cd in the soil was mainly in the residual state,Fe/Mn oxide binding state and exchangeable state,and the heavy metal Cd was mainly in the difficult to use state,followed by the available state.Based on the potential ecological risk index method and risk assessment code(RAC),the ecological risk of heavy metal Cd in soil was evaluated,and the potential ecological risk of Cd pollution was relatively strong.On the basis of the above research,the potential ecological risk of heavy metals was evaluated based on the ArcGIS10.0 software and the potential ecological risk index method.The potential ecological risk of soil heavy metal Cd in the northeast and southeast of the study area was higher than that in other study areas.