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研究报告

摘要：北三河水系包括接纳了北京、天津大量再生水和污水的温榆河、凉水河和北运河等河流,其沉积物中金属的污染状况是水环境质量的重要指标之一.本研究调查分析了北三河水系8条河流沉积物中金属的污染状况及存在形态,采用地累积指数评价了金属的污染级别,利用相关性分析和主成分分析简要分析了金属的主要来源.研究结果表明,北三河水系沉积物中Fe、Mn、Zn、Cr、Cu、Ni、Pb、Co和Cd的平均浓度分别为24207、538、303、57、48、29、15.2、14和0.27 mg·kg^-1.牛牧屯河部分沉积物中Fe、Zn、Cu、Cr和Ni的浓度高于沉积物质量基准(SQG)中的极有可能产生危害的浓度(PEC)值,很有可能对生物产生危害;而温榆河、还乡河、北运河、凉水河和潮白河中大部分金属浓度高于产生危害的阈值(TEC)而低于PEC水平,也应列入防控对象.河流沉积物中金属积累级别较高的河段多位于郊区和乡镇,可能因为这些区域污水处理率较低.Fe、Cr、Ni、Cu、Mn和Zn在沉积物中主要以残渣态存在,其比例分别可达92.5%、85.2%、87.9%、71.0%、63.4%和57.3%;Pb则主要以可提取态存在,其比例为62.6%.沉积物中Cu、Pb、Ni和Cd元素的存在主要受人类活动的影响,其在北三河水系沉积物中的分布主要受有机碳的控制;Cr和Co的存在则主要受自然因素的影响,其分布主要受铁锰氧化物或矿物质的影响.

Abstract：Beisan River System consists of Wenyu River, Liangshui River, Beiyun River, etc., which receives most wastewater discharge from Beijing and Tianjin.The contamination of metals in sediment of the rivers is an important parameter for evaluating the quality of water environment.In this study, the levels and speciation of metals in sediment from Beisan River System were investigated and the pollution class was evaluated with the CSST sediment quality guideline and geo-accumulation index.The sources of the metals were estimated with correlation analysis and principal component analysis.The results showed the average concentration of Fe, Mn, Zn, Cr, Cu, Ni, Pb, Co and Cd was 24207, 538, 303, 57, 48, 29, 15.2, 14 and 0.27 mg·kg^-1, respectively.The pollution class of metals in sediments from Niumutun River was the highest in the 8 rivers investigated.In the sediments investigated, Fe, Cr, Ni, Cu, Mn and Zn mainly existed in residual fraction, with the ratio of 92.5%, 85.2%, 87.9%, 71.0%, 63.4% and 57.3%, respectively.Pb mainly existed in the extractable fraction with the ratio of 62.6%.Cu, Pb, Ni and Cd in the sediments were mainly influenced by anthropogenic factor and the distribution of these elements was mainly controlled by the content of total organic carbon.In comparison, Cr and Co were mainly influenced by natural factor and the distribution was mainly controlled by Fe and Mn oxides or clay mineral.