乐安江湾头镇段底泥重金属元素的垂直污染分布特征

Perpendicularity Contamination and Distribution Characteristics of Heavy Metal Elements in the Sediments at the Section of Wantou Town of Le An River

采集乐安江中游湾头镇段底泥57cm长的柱状样，采用微波消解、ICP—AES检测底泥柱状样重金属元素的含量，来探讨重金属元素垂直污染分布规律与年度分布特征。底泥样品中Pb、Ni、cr的平均值分别为4．94mg／kg、30．58mg／kg、66．88mg／kg，均在土壤环境质量标准一级标准以内。Zn的平均值为421．38mg／kg，大部分样品在土壤环境质量标准三级标准以内，部分样品远超过三级标准。cu的平均值为203．57mg／kg，是土壤环境质量标准二级标准的2倍多。不同深度的底泥柱状样重金属的含量不一样，Cu在深度18～22cm时有最大值（471．79mg／kg）。底泥柱状样的分析可以反映河流不同年代重金属的污染情况。

To investigate the distributing disciplinarian of perpendicularity contamination and characteristics of years distribution of heavy metal elements, samples from sediments whose depth was from 0 to 57 cm at the section of Wantou town of Le An River were collected. The samples were pretreated by Microwave digestion and determined by ICP - AES. The results showed that the average values of Pb,Ni,Cr in the sediments were 4.94 mg/kg,30.58 mg/ kg and 66.88 mg/kg separately,which were within the first scale standard of Soil Environment Quality. The average value of Zn was 421.37 mg/kg,the Zn concentrations of most of the samples were within the third scale standard of Soil Environment Quality, however part of the samples farly exceeded the third scale standard . The average value of Cu was 203.57 mg/kg,which was 2 times of the second scale standard of Soil Environment Quality. The concentrations of heavy metal elements in the post shape samples of sediment were unlikeliness with the depth. There was the biggest concentration（471.79 mg/kg）of Cu at the depth of 18 - 22 cm. Analysis results of the post shape samples of sediment could reflect contamination state of heavy metals of river in the different years.