长江南京段沉积物元素特征及地球化学意义

Elemental characteristics and geochemical significance of sediments in Nanjing section of Yangtze River

采集了长江南京八卦洲段悬浮物、漫滩柱状沉积物和表层沉积物样品,分析了Al、Fe、Mn、Hg、Ni、Cr、Cu、Pb、Cd、Co、Zn含量。结果表明,柱状沉积物元素含量垂向变化较小,反映沉积物来源比较稳定;表层沉积物微量元素含量因子分析反映元素主要受流域地质影响,Cd、Cu、Pb、Zn等元素还叠加人为活动的影响;悬浮物与长江中下游成矿带地质体的Pb同位素206Pb/207Pb比值非常接近,表明长江中下游成矿带来源悬浮物携带以Cd为代表的重金属对江苏沿江土壤重金属富集胚层起着重要的塑造作用。

The authors collected systemically the samples on the suspensions,sedimentary columns and surface sediments in Nanjing section in the Yangtze River and analyzed their concentrations of Al,Fe,Mn,Hg,Ni,Cr,Cu,Pb,Cd,Co and Zn.It was concluded that,the vertical variation for the element concentration of columnar sediments was small;reflecting the sources of sediments was steady.The principal factor analysis of trace elements in surface sediments suggested that element concentrations were dominated by valley geology;however,the elements of Cd,Cu,Pb and Zn were principally associated with human activities.Similar isotope ratios between suspensions and geological mass in metal deposits along the middle and lower reaches of Yangtze River,suggesting Cd-enriched heavy metal carried by the suspension from the metallic belt of the middle and lower reaches of Yangtze River played an important role in the enrichment and molding of soils and heavy metals in deposits along the Yangtze River in Jiangsu Province.