赫章土法炼锌区水-沉积物重金属污染的时空变化特征

Spatial and Temporal Variation Characteristics of Heavy Metal Pollution of Water-sediments in Stream of Zinc Smelting Area,Hezhang of Guizhou,China

对赫章土法炼锌区河流水体和沉积物重金属污染状况及时空变化特征进行了研究。结果表明,水体和沉积物受到多种重金属污染:地表水体中Pb、Zn、Cd的均值分别为137.19×10-3、1 919.38×10-3、14.21×10-3 mg.L-1,分别是地表水环境质量标准Ⅲ类水质标准的2.74、1.91、2.84倍;沉积物中Cu、Pb、Zn和Cd的均值分别为702.79、3 242.8、5 427.6、32.19 mg.kg-1,分别是土壤环境质量标准三级标准的1.76、6.49、10.86、32倍。水体和沉积物中Cu、Pb、Zn和Cd沿河流总体呈无规律性的变化,受炼锌废渣堆和铅锌选矿厂影响的地点,水体和沉积物重金属含量均较高,污染严重。近10年来,炼锌区河流水体和沉积物重金属污染仍然很严重,水体重金属污染呈加重特征,沉积物中Pb、Zn污染呈减轻趋势,Cd和Cu污染则加重。

The spatial-temporal variations of heavy metals in water and sediments of a stream affected by zinc smelting industry in Hezhang,Guizhou Province,were studied.It was found that water and sediments had been polluted by heavy metals.The average concentrations of lead,zinc and cadmium in surface water were respectively 137.19×10-3,1 919.38×10-3 and 14.21×10-3 mg·L-1,which were 2.74,1.91 and 2.84 times of Class Ⅲ of environmental quality standards for surface water,respectively.Also,the average concentrations of copper,lead,zinc and cadmium in sediments were 702.79,3 242.8,5 427.6 and 32.19 mg·kg-1,which were 1.76,6.49,10.86 and 32 times as much as the Class Ⅲ of soil environmental quality standard,respectively.Affected by the waste residue of zinc smelting and lead or zinc processing factories,concentrations of copper,lead,zinc and cadmium varied in both water and sediments along the river.In last decade,it was found that concentrations of heavy metals increased in water,which showed serious pollution in the study area.However,the contents of lead and zinc in sediments decreased and that of cadmium and copper increased at the same period.