安徽迪沟采煤沉陷区土壤和沉积物重金属特征及潜在生态风险评价

为了解迪沟采煤沉陷区重金属特征与污染状况,采集沉陷区23个土壤样本和35个沉积物样本,分析了铜(Cu)、锌(Zn)、铅(Pb)、镉(Cd)和砷(As)5种重金属的含量,并运用地累积指数法和潜在生态危害指数法评价了迪沟采煤沉陷区土壤沉积物和土壤重金属污染状况以及综合潜在生态风险。结果表明:土壤中As、Cd和Cu的含量高于背景值,沉积物中As、Cu、Cd、Pb的含量高于背景值;21.7%土壤样本中的Cd和80%沉积物样本中的As含量明显高于农用地土壤污染风险筛选值,但低于污染风险管制值;迪沟采煤沉陷区重金属含量整体表现为陆域低于水域、中部区域较高、东西部区域较低的特点。地累积指数评价结果表明,迪沟采煤沉陷区土壤和沉积物污染总体表现为未污染到轻度污染,主要污染物为As和Cd。潜在生态风险指数法评价结果表明,迪沟采煤沉陷区土壤和沉积物潜在生态风险低,重金属潜在生态危害依次为CdAsCuPbZn。研究表明,迪沟采煤沉陷区土壤和沉积物重金属总体生态污染风险较小,但不能忽视Cd和As的潜在污染风险。

Heavy metal characteristics and potential ecological risk assessment of the soil and sediment in the Digou coal mining subsidence area, Anhui, China

Understanding the characteristics and contamination status of heavy metals in the Digou coal mining subsidence area will shed light on how to use water and land appropriately. We collected 23 soil samples and 35 sediment samples in the subsidence area and analyzed the content of elements Cu, Zn, Pb, Cd, and As. We evaluated the status of heavy metal pollution and the potential ecological risks of the soil and sediment in the Digou coal mining subsidence area using the geological accumulation index and potential ecological hazard index methods. The results revealed the following:the As, Cd, and Cu content in the soil and sediment, and the Pb content in the sediment, is higher than the background value; the Cd content in 21.7% and 80% of soil and sediment samples, respectively, is significantly higher than the soil pollution filtered risk value of agricultural land, but still lower than the pollution risk control value; the overall heavy metal content in the Digou coal mining subsidence area is lower in the land area than the water area, higher in the central area, and lower in the east and west areas; and according to the evaluation results of the geoaccumulation index, the soil and sediment pollution status in the Digou coal mining subsidence area generally ranges from clean to slightly polluted, and the main pollutants are As and Cd. According to the evaluation results of the potential ecological risk index, the ecological risk of the soil and sediment in the Digou coal mining subsidence area is low, and the sequence of potential ecological hazards of heavy metals is Cd>As>Cu>Pb>Zn. The overall ecological pollution risk of the soil and sediment in the Digou coal mining subsidence area is relatively low, but the potential pollution risk of Cd and As should not be ignored.