东苕溪中下游沉积物重金属污染特征与评价

Distribution Characteristic and Environmental Assessment of Heavy Metals in Sediment from Middle-Lower Reaches in East Tiaoxi River

于2009年10月和2010年5月在东苕溪中下游河段采集沉积物样品34个,测定了沉积物中As、Cd、Cr、Cu、Hg、Ni、Pb和Zn的含量,并用地积累指数法对沉积物中重金属污染进行评价分析。结果表明,Hg和Ni含量属于国家一级土壤标准;Cr、Cu、Pb、Zn含量基本属于国家一级至二级土壤标准;2009年As含量属于国家一级至二级土壤标准,2010年As含量属于国家二级至三级土壤标准;Cd污染最严重,属于国家三级土壤标准。采用地积累指数法对东苕溪中下游沉积物中重金属的污染状况进行评价,结果显示,Cd污染最严重,As次之,Cr污染最轻;东苕溪中下游河段76.5%的样品重金属浓度具有增大的趋势。

Thirty-four sediment samples were collected from middle-lower reaches of East Tiaoxi River in October 2009 and May 2010.The concentrations of As,Cd,Cr,Cu,Hg,Ni,Pb,Zn in the sediments were measured and heavy metal pollution was assessed with index of geoaccumulation.The results showed that the contents of Hg and Ni did not exceed the standards of Grade I of National Environmental Quality Standard for Soils in China;the contents of Cr,Cu,Pb,Zn were mainly between the standards of Grade I and Grade II;the content of As was changeable which was between the standards of Grade I and Grade II in October 2009,while it was between the standards of Grade II and Grade III in May 2010;the content of Cd was mostly belong to Grade III.Results with integrative index of geoaccumulation showed that the pollution of Cd was the most serious;As took the second place;Cr was the best of all heavy metals;The integrative index of geoaccumulation in 76.5% sampling sites showed an increasing trend of pollution.