珠江三角洲地区地下水中卤族元素质量浓度背景特征及成因分析

Background features and origin analysis of contents of halogen elements in groundwater of Pearl River Delta

利用珠江三角洲地区1∶25万区域地下水污染调查评价项目所取得的水质数据,采用数理统计方法,在判断元素质量浓度分布类型的基础上,计算该地区卤族元素质量浓度的背景集中特征值和背景值范围,并对背景值统计特征及分布规律进行分析。结果表明,浅层地下水受人类活动影响较大,多呈偏态分布;地下水中卤族元素的分布主要受岩土性质、地下水径流条件、氧化还原环境的影响,另外,Cl、Br的背景质量浓度受海水入侵作用的影响明显,F的高背景质量浓度与温泉出露密切相关。对地下水中卤族元素质量浓度背景值的研究将为地方病防治工作提供重要科学依据。

The natural background levels and ranges of the contents of halogen elements in the Pearl River Delta were calculated and the statistical features and regularity of distribution were analyzed using regional groundwater data at a scale of 1∶ 250 000 and the mathematical statistics method,based on judgment of the distribution patterns of the contents of halogen elements.The results show that the shallow groundwater,influenced by anthropogenic activities,exhibited skewed distribution.The distribution of the halogen elements was mainly affected by rock properties,groundwater runoff conditions,and redox conditions.In addition,the background levels of Cl and Br contents were closely related with seawater intrusion while the high value of F was controlled by the occurrence of thermal springs.Study of natural background levels of the contents of halogen elements would provide a scientific basis for prevention and control of endemic diseases.