温榆河水体中重金属含量分布及赋存状态解析

利用错流超滤技术对采集的温榆河水样中Fe、Mn、Al、Zn、Cu、Cr和Pb等金属元素进行了分离,研究温榆河重金属分布及赋存状态变化.研究发现,温榆河沿程重金属含量多数超出了《地表水环境质量标准》(GB3838—2002)的Ⅰ类水标准,Pb超过了Ⅱ类水标准;其中Fe、Al、Cu、Pb等元素主要以颗粒态存在,Mn、Zn则主要以溶解态存在,而Cr在颗粒态和溶解态中含量相当.温榆河沿程各点金属元素在胶体态和真溶解态中均有分布,Mn、Al、Zn、Pb等元素以真溶解态存在量较多,而Fe、Cr、Cu等元素则以胶体态存在量较多,其中,河流中的Cu元素分布状态受外界影响严重,Cr和Mn的分布状态不易受外界因素影响,Fe的分布状态易受总含量的影响,Al和Zn的分布状态易受pH值的影响,Pb的分布状态易受河流富氧状态的影响.通过胶体态重金属与胶体态有机碳的相关性分析发现,温榆河中胶体态Fe、Mn、Zn及Al主要以无机胶体态存在;而胶体态Cu、Cr和Pb则主要以有机胶体态存在.

Distributions of trace metals in the surface water in Wenyu River

Trace metals such as Fe,Mn,Al,Zn,Cu,Cr and Pb from surface water in Wenyu River were isolated using the cross-flow ultrafiltration technique.The concentrations and distributions of these trace metals were investigated in this study.The results showed that the concentrations of most heavy metals in Wenyu River were higher than the Class Ⅰ of the environmental quality standards for surface water(GB 3838—2002) .Fe,Al,Cu and Pb mainly existed in the granular form,while Mn and Zn mainly existed in the dissolved form.Among the dissolved forms,Mn,Al,Zn and Pb mostly existed in true dissolved forms with molecular weights lower than 1 kDa,while Fe,Cr and Cu mainly existed in the colloidal form with molecular weights higher than 1 kDa.The distributions of trace metals were affected by the external factors,especially Cu.The distribution of Fe tended to be affected by the total concentration,Al and Zn by pH,and Pb by dissolved oxygen.In comparison,the distributions of Cr and Mn were hardly affected by external factors.According to the correlations between concentrations of colloidal Cu,Zn,Cr,Fe,Mn,Al,and Pb and colloidal organic carbon in the 1 kDa～0.22 μm fraction,colloidal Fe,Mn,Zn and Al predominantly existed in the inorganic colloidal form,while colloidal Cu,Cr and Pb mainly existed in the organic colloidal form in Wenyu River.