对广东省雷州半岛 2009-2017 年地下水环境质量调查项目涉及的 102 个钻孔的水化学数据进行分析,发现该区域地下水的铁(Fe)、锰(Mn)含量和 pH普遍超标,导致当地地下水水质以Ⅳ~Ⅴ类居多,不适宜直接作为生活饮用水.其中,中层含水层的 Fe、Mn超标最显著,且二者具有十分一致的水文地球化学行为特征,因此,该层是解析超标机理的关键层位.松散沉积含水层的 Fe、Mn、pH超标问题比基岩裂隙溶隙含水层和交互含水层更突出.湛江组和北海组两个相邻松散岩类地层均含有丰富的铁锰质矿物或结核,应加强对这两个地层的地球化学分析,以进一步解析相关指标超标的地球化学机理.最后,就该区域地下水水质超标机制研究与水质管控提出了建议.
Based on the analysis of the hydrochemical data of 102 boreholes obtained from the groundwater environmental quality surveys in Leizhou Peninsula of Guangdong Province from 2009 to 2017,it was found that the Fe and Mn content and pH of the groundwater in this area genenally exceeded the standard,resulting in the majority of class Ⅳ-Ⅴ grades in the classification for groundwater quality,which is not suitable to be directly used as drinking water.The highest levels of excessive Fe and Mn were found in the middle aquifer,where Fe and Mn exhibited consistent hydrogeochemical behaviour characteristics,indicating that it was the key layer for analyzing the mechanism of exceeding the limit.Compared with bedrock fissure aquifers and interacted aquifers,unconsolidated sedimentary aquifers had the most prominent problems of Fe,Mn and pH exceeding the national drinking water standards.The two adjacent unconsolidated sedimentary strata of Zhanjiang Formation and Beihai Formation were rich in ferric manganese minerals or nodules.The geochemical analysis for these two strata should be strengthened to further analyze the geochemical mechanism of the excess of the relevant indicators.Finally,suggestions on the study of the mechanism of groundwater quality exceeding the standard and groundwater quality control in this region were put forward.