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.
heavy metalZi Riversedimentstone coalsource identificationpollution assessment
万方数据
维普
