钒钛磁铁矿冶炼渣场周边土壤-鱼塘-河流系统中钒铬分布特征及生态风险评价

Distribution Characteristics and Ecological Risk Assessment of Vanadium and Chromium in Soil-fishpond-river System around Vanadium Titanium Magnet Smelting Slag Field

为探究冶炼废渣中钒(V)和铬(Cr)对周边环境的影响,采集渣场周边土壤、沉积物、鱼塘底泥、鱼塘水和河水样品,分析V和Cr的浓度、赋存形态,并采用富集因子法、地质累积指数法和潜在生态风险指数法对V和Cr的污染状况和生态风险进行评价。结果表明,研究区土壤中V和Cr平均含量分别约为四川省背景值的2.6和4.0倍,富集程度分别为轻微和中度富集;沉积物中V、Cr平均含量分别约为对照沉积物的5.0和3.2倍,底泥中V、Cr平均含量分别约为对照沉积物的5.5和1.4倍,V和Cr富集程度均为中度和轻微富集;水样表现为V污染,鱼塘水和河水V平均浓度分别约为金沙江水样的17.6和1.8倍。研究区V和Cr主要以残渣态形式存在于土壤中,其占比分别为57.1%和89.4%,沉积物和底泥中V和Cr残渣态占比分别为20.1%和74.9%,各环境介质中V的生物可利用率及迁移率要远高于Cr;结合V和Cr地球化学性质分析,研究区环境介质中V和Cr可能主要以V 5+和Cr 3+形式存在。污染评价结果表明,土壤中V、Cr污染程度分别为轻微和中度污染,沉积物与底泥中V、Cr污染程度分别为中度和轻微污染,V和Cr均对生态系统构成轻微风险。因此,为保护研究区域生态系统和公共健康,应尽快修复受污染土壤和沉积物。

To investigate the impact of V and Cr from smelting slag on the surrounding environment,samples of soil,sediment,pond bottom mud,pond water and river water were collected.The concentration and occurrence form of V and Cr were analyzed,and their pollution status and ecological risk of V and Cr were evaluated by using enrichment factor method,geological accumulation index method and potential ecological risk index method.The study reveals that the mean concentrations of V and Cr in the soil of the study area were 2.6 and 4.0 times of the background value in Sichuan Province,with slight and moderate degrees of enrichment.Additionally,the mean concentrations of V and Cr in the sediment were 5.0 and 3.2 times of those in the control sediment,while the mean concentrations of V and Cr in the pond bottom mud were 5.5 and 1.4 times of those in the control,respectively.The degree of V and Cr enrichment was moderate and slight.The water samples exhibited V pollution,and the average concentration of V in fishpond and Baguan River water being roughly 17.6 and 1.8 times of that of Jinsha River water samples,respectively.In the study area,V and Cr primarily exist in the residual fraction in the soil,accounting for 57.1%and 89.4%,respectively.The residual fraction of V and Cr in the sediment and pond bottom mud accounts for 20.1%and 74.9%,respectively.The bioavailability and mobility of V in each environmental medium of the study area is much higher than that of Cr.Combined with the analysis of the geochemical properties of V and Cr,V and Cr in the environmental medium of the study area may exist mainly in the form of V 5+and Cr 3+.The pollution evaluation results indicate that the contamination levels of V and Cr in the soil were slight and moderate,whereas both V and Cr in sediment showed slight and moderate contamination.Consequently,both V and Cr pose a slight risk to the ecosystem.Therefore,it is imperative to remediate the contaminated soil and sediment promptly to safeguard the ecosystem and public health in the study area.