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本次工作利用等离子质谱仪(ICP-MS)对湘江长沙-湘潭-株洲河段河床沉积物重金属含量和铅同位素组成进行了系统的分析。结果表明,河床沉积物富集V、Cr、Mn、Co、Ni、Th、U、Cu、Pb、Zn等多种重金属,其中Cu、Zn、Pb等重金属于株洲段沉积物中达高度至极度富集。沉积物重金属的富集特征暗示沉积物存在较严重的重金属污染。沉积物铅同位素组成以相对富Th铅为特征,具明显的人为源和自然源铅,其~(206)Pb/~(207)Pb值在1.1723至1.1855之间,~(206)Pb/~(208)Pb值在0.4760至0.4786之间。其中自然源铅主要为花岗岩铅,而人为源铅则为铅锌矿矿石铅和燃煤铅构成,即沉积物铅同位素组成为花岗岩铅、铅锌矿矿石铅、燃煤铅组成的三元混合铅。铅同位素比例估算显示,长沙、湘潭段沉积物铅锌矿矿石源铅比例平均依次为23%、32%,燃煤源铅比例平均依次为47%、23%,自然源铅比例平均依次为30%、45%;株洲段沉积物的自然源铅比例较低,平均为17%,而矿石铅和燃煤铅的比例较高,平均依次为34%和49%。V、Mn、Co、Cu、Zn、U等其他重金属与Pb一样,长沙、湘潭段沉积物人为源比例小于67%,株洲段沉积物人为源比例达70%。因此,湘江长潭株段河床沉积物重金属污染问题值得引起高度重视。
In this work, ICP-MS was used to systematically analyze heavy metal contents and lead isotopic compositions of river sediments in the Xiangjiang-Xiangtan-Zhuzhou reach. The results show that riverbed sediments are enriched in heavy metals such as V, Cr, Mn, Co, Ni, Th, U, Cu, Pb and Zn, Enriched. Accumulation characteristics of heavy metals in sediments imply severe heavy metal pollution in sediments. The Pb isotopic compositions of sediments are characterized by relative abundance of Th lead with significant anthropogenic and natural source lead with ~ (206) Pb / ~ (207) Pb ranging from 1.1723 to 1.1855 and ~ (206) Pb / ~ (208) Pb values between 0.4760 and 0.4786. Among them, natural lead is mainly granite lead while man-made lead is composed of lead-zinc ore lead and coal-fired lead. The lead isotopic composition of sediments is granite lead, lead-zinc ore lead and coal-fired lead. lead. Lead isotope ratio estimates show that the lead-zinc ore deposits in the sediments of Changsha and Xiangtan are 23% and 32% on average, respectively, with an average percentage of lead and lead of 47% and 23%, respectively, and that of natural lead is 30% %, 45%. The sediments in Zhuzhou have a lower proportion of natural source lead, with an average of 17%. The proportions of lead and coal are higher with 34% and 49% respectively on average. Other heavy metals such as V, Mn, Co, Cu, Zn and U, like Pb, accounted for less than 67% of the sediments in Changsha and Xiangtan, and 70% of the man-made sediments in Zhuzhou. Therefore, the Xiangtan Changtan strain bed sediment heavy metal pollution deserves great attention.