资水下游某石煤矿区沉积物重金属污染评价和来源解析

以资水下游某石煤矿区为研究区域，分析该矿区河流沉积物中重金属的空间分布、污染程度和来源。研究共采集了28个表层沉积物样本，并对其中8种重金属的含量进行了测定，包括镉（Cd）、铬（Cr）、汞（Hg）、砷（As）、铅（Pb）、铜（Cu）、镍（Ni）和锌（Zn）。采用地累积指数和潜在生态风险指数进行重金属污染评价，运用主成分分析（PCA）、正定矩阵因子（PMF）等方法识别重金属污染来源。结果表明，除Cr外，Cd、Hg、As、Pb、Cu、Zn、Ni含量的中值均高于洞庭湖水系沉积物背景值。其中，Cd、As含量超标问题较为严重，超过《土壤环境质量 农用地土壤污染风险管控标准（试行）》（GB 15618—2018）风险筛选值的样点比率分别为96.55%、58.62%。地累积指数和潜在生态风险指数分析表明，沉积物中Cd、Hg污染最为严重，Cr污染程度最低。沉积物重金属主要来源为石煤开采源、交通和农业混合源、自然源以及大气沉降源，贡献率分别为33.8%、20.4%、17.7%和28.1%。研究表明，研究区沉积物受到石煤开采影响，重金属Cd超标严重，应加强管控。

Evaluation assessment and source analysis of heavy metals in sediment near the stone coal mining area in the lower reaches of the Zi River，China

In this study, the downstream area of a shale coal mining site located along the Zi River was selected as the research area to analyze the spatial distribution, pollution levels, and sources of heavy metals in the river sediment of the mining region. A total of 28 surface sediment samples were collected, and the concentrations of eight heavy metals were determined：cadmium（Cd）, chromium（Cr）, mercury（Hg）, arsenic（As）, lead（Pb）, copper（Cu）, nickel（Ni）, and zinc（Zn）. The Geo-Accumulation Index and Potential Ecological Risk Index were employed to assess the level of heavy metal pollution. Various methods, such as Principal Component Analysis（PCA） and Positive Matrix Factorization（PMF）, were applied to identify the sources of heavy metal pollution. The results indicated that apart from Cr, the median concentrations of all heavy metals were higher than the background values of the sediment in the Dongting Lake Basin. Specifically, Cd and As demonstrated severe contamination, with the percentage of sampling points exceeding the risk screening values specified in the Soil Environmental Quality Risk Control Standard for Soil Contamination of Agricultural Land（Trial）（GB 15618—2018） being 96.55% and 58.62%, respectively. The Geo-Accumulation Index and Potential Ecological Risk Index analysis showed that Cd and Hg were the most severe pollutants in the sediment and Cr the least. The main sources of heavy metals in the sediment were identified as shale coal mining, mixed sources from transportation and agriculture, natural sources, and atmospheric deposition, contributing 33.8%, 20.4%, 17.7%, and 28.1%, respectively. In summary, the sediments in the study area are seriously affected by the mining of stone coal, leading to the serious exceedance of Cd content. Therefore, pollution management and control should be strengthened.