中文摘要：

以大兴区为研究对象,基于全区99眼机井的地下水水质调查结果,应用数学统计分析方法和水文化学分析软件,研究了北京南部地区地下水中氟化物的分布特征及成因。结果表明：该区域地下水化学类型相对比较简单,以HCO3-Ca.Mg型为主。氟化物在研究区地下水中广泛分布,影响着地下水水质状况。浅层地下水中氟化物浓度变化范围在0.13～1.76mg/L之间,浓度高值区主要分布在研究区南部和东南部。与浅层地下水相比,深层地下水中氟化物浓度较低,未出现超标现象。地下水中氟化物浓度与pH值及Ca2＋浓度分别呈正、负相关关系,与取水深度也存在一定相关关系。地下水中氟化物主要由自然因素造成,但近年来人类频繁活动也影响着水体中氟化物浓度变化。

英文摘要：

The article is focused the distribution characteristic and causes of fluoride in groundwater of the Daxing District by applying mathematics statistical methods and hydrochemical analysis software,based on the groundwater quality survey results of 99 wells in the region.The results show that groundwater chemical type is relatively simple and mainly HCO3-Ca·Mg type water.Fluoride in groundwater is widely distributed in the study area,and has an effect on the groundwater quality.Fluoride concentrations in shallow groundwater range from 0.13 to 1.76mg/L.The areas of high concentration are mainly distributed in south and southeast of the study area.Compared with the shallow groundwater,the fluoride concentrations in the deep groundwater are lower,and the excessive phenomenon does not appear.Fluoride concentration in groundwater has separately positive and negative correlation with pH value and Ca2＋ concentration,and also has some correlation with water depth.Fluoride in groundwater is mainly caused by natural factors,in addition,frequent human activities also affect the fluoride concentration in recent years.