松花江表层沉积物重金属空间分布及生态风险评价

Spatial Distribution and Ecological Risk Assessment of Heavy Metals in Surface Sediments from Songhua River

为探究松花江表层沉积物重金属的分布特征和来源,2014年4月采集松花江16份表层沉积物样品。采用全分解法对样品进行消解;并分析重金属Cu、Zn、Cr、Ni、Cd、Pb、As、Hg。结果表明,除Zn和Cr外,其他重金属平均含量高于背景值。参照TEL-PEL生态风险评估体系,Ni、Cu、As、Cd具有一定生态风险,其中Ni、As对底栖动物生态风险较强。高含量的重金属出现河段为中上游水体,通化和吉林市河段水体沉积物重金属含量较高。重金属Cu、Zn主要来自于生活污水的排放,高浓度Cr、Cd、Hg主要来自于工业废水排放,As来自于岩石风化过程。松花江中上游水体大部分点位表层沉积物重金属毒性单元>4,处中-高毒性水平;而下游水体毒性较低。重金属平均毒性呈As>Ni>Cr>Pb>Zn>Cd>Cu>Hg,其中As和Ni贡献率最高。

In order to study the spatial distributions and sources of heavy metals in surface sediments from Songhua River,16 surface sediments were collected in April 2014. The sediments were subjected to a total digestion technique and analyzed for Cu,Zn,Cr,Ni,Cd,Pb,As and Hg. Results showed the average concentrations of all the heavy metals except Zn and Cr were higher than background values. Based on TEL-PEL ecological risk assessment,certain ecological risks were possessed by Ni,Cu,As and Cd,in which Ni and As had strong risks to the benthonic animals. Patches with higher heavy metal concentrations occurred on the middle and upper reaches of Songhua River and sediments with higher heavy metal concentrations were located in the river reaches of Tonghua and Jilin. The heavy metal loads such as Cu and Zn might come from the common sources due to domestic sewage,while higher concentrations of Cr,Cd and Hg might come from the common sources due to industrial sewage. However,As dominated by parent rocks. Heavy metals in surface sediments from the middle and upper reaches of Songhua River were higher than 4,indicating moderate-high toxicity. The average heavy metal toxic units decreased following the order As Ni Cr Pb Zn Cd Cu Hg with higher contributions of As and Ni.