华北平原地下水重金属山前至滨海空间分布特征与规律

Spatial Distribution of Heavy Metals in Groundwater from the Piedmont to Coastal Areas in the North China Plain

结合华北平原水文地质条件,从山前至滨海选取"保定-沧州"、"石家庄-衡水-德州"两个剖面,通过野外采集地下水样品,分别测定了Fe、Mn、Cu、Zn、Pb、Cd、As、Cr、Se等9种重金属元素含量及其他相关指标。结果表明,调查剖面地下水中出现Fe、Mn、Se、Cr超标现象,其中Fe超标严重。本文首次在区域尺度上对华北平原地下水重金属的空间分布进行了分析,分别阐述了两个剖面地下水重金属的横向与垂向分布特征。总体上,随着地下水埋藏深度的增加,重金属离子总量降低,尤其是对人体有害的重金属元素含量降低显著。通过回归分析对地下水中重金属空间变化规律进行了定量分析,其中Cd、As、Zn、Mn元素含量与空间变量呈现显著相关性。本研究结果可为华北平原地下水质量评价与防控提供一定的依据。

Based on the hydrogeologic conditions of the North China Plain, two typical cross sections ＂Baoding-Cangzhou＂ and ＂Shijiazhuang-Hengshui-Dezhou＂ along groundwater gradients from the piedmont to coastal areas in the North China Plain were selected and the groundwater samples were taken twice in a hydrologic year. The concentrations of Fe, Mn, Cu, Zn, Pb, Cd, As, Cr, Se were analyzed. The analytical results show that Fe, Mn, Se, Cr in groundwater exceed the drinking water stand- ards, especially that of Fe. The spatial distribution characteristics of the heavy metals in groundwater of the North China Plain were investigated at regional scale for the first time, horizontally and vertically, respectively. In general, the total amount of heavy metals in groundwater reduces with the increase of depth, especially the harmful elements. Moreover, the relationships between the concentrations of the heavy metals and the space variables including distance away from the piedmont, and depth were established by using the regression method. It is indicated that the concentrations of Cd, As, Zn and Mn show significant correlation with those space variables. The investigation results are expected to have certain implications to the evaluation and control of the groundwater quality in the North China Plain.