湘潭市锰矿工业区某渠道重金属污染特征

Study of the Characteristics of Heavy Metals Pollution in a Ditch of the Manganese Ore Industrial Zone of Xiangtan City

文章分析了湘潭市锰矿工业区某渠道13个采样点沉积物中Mn、Cd、Pb、Zn和Cr的浓度水平,并采用地积累指数法(Igeo)和潜在生态风险指数法(RI)对其污染现状进行评价。结果表明,渠道沉积物中Cd、Mn、Pb、Zn和Cr平均浓度均高于《全国土壤污染状况评价技术规定》标准值,分别为标准值的107.1、31.42、15.28、7.44和3.32倍。Igeo评价结果表明,渠道沉积物中Igeo表现为Cd>Mn>Pb>Zn>Cr,Cd和Mn的Igeo分别为4.65和3.34;不同采样点Itot(重金属综合积累指数)呈9#>8#>3#>6#>5#>1#>7#>4#>2#>11#>12#>13#>10#的分布特征,8#和9#两个采样点Itot均大于20.0。RI评价结果表明,各污染物对渠道生态风险构成危害的影响程度为Cd>Pb>Mn>Zn>Cr,整个渠道的RI为64.63~19 974.64,平均值为3 316.58,具有极强潜在生态危害。

In this study,the concentrations of heavy metals such as Mn,Cd,Pb,Zn and Cr in the thirteen sediment samples from a ditch of the manganese ore industrial zone of Xiangtan City were analyzed,and geo-accumulation index(I geo)and potential ecological risk index(RI)were used to evaluate the pollution status.The results indicated that the average values of w(Cd),w(Mn),w(Pb),w(Zn)and w(Cr)in the sediments were all higher than the standard values regulated in the provisions for the evaluation technologies of the national soil pollution status,with the average values of 107.1,31.42,15.28,7.44 and 3.32 times respectively of the standard values.The values of I geo in the sediments were ranked in the order of Cd>Mn>Pb>Zn>Cr.The values of I geo of Cd and Mn were 4.65 and 3.34 respectively.The values of I tot presented in the order of 9#>8#>3#>6#>5#>1#>7#>4#>2#>11#>12#>13#>10#,and the values of I tot at 8#and 9#of the sampling points were both over 20.0.Evaluation results of RI showed that the effect degrees of the pollutants on the ecological hazard risks to the ditches were ranked in the order of Cd>Pb>Mn>Zn>Cr.The average RI was 3 316.58(ranging from 64.63 to 19 974.64),indicating an extremely serious ecological risk.