中文摘要：

大荔县地处渭河断陷盆地东部，潜水中氟含量较高，氟的赋存受水文，气候，地形地貌、地质背景、水文地质、水文地球化学等多种因素的制约，根据浅层地下水调查资料采用美国地质调查局的PHREEQC软件来研究地下水中氟赋存规律。该地区降雨量小，蒸发强烈，高氟水的成因可分为，蒸发浓缩型和溶滤富集型。岩性主要为黏土、亚黏土、细砂，孔隙小，富含氟的矿物成分为地下水中高氟提供了丰富的物质来源。地下水水位埋深浅，包气带中毛细上升高度高，导水性差，多层交互含水层结构为高氟地下水提供了得天独厚的赋存条件。结合水文地球化学的作用，研究了氟与其主要络合离子的存在形式和组分浓度以及它们的矿物来源的溶解-沉淀情况，来揭示氟在地下水径流方向上的演化规律。

英文摘要：

The Dali county lies in the eastnorth sag region of Wei river down-faulted basin, There are many factors affecting the shallow groundwater fluorine occurrence, such as the hydrology, climate, terrain, geological background, hydrogeologic conditions and hydrogeochemistry in this area. Based on the shallow groundwater survey data and USGS＇ PHREEQC software, We studied the occurrence characteristics of fluoride in groundwater. The precipitation of the study area is low and the evaporation is strong. The type of high fluoride is evaporation and enrichment, or dissolution and enrichment. The main lithology is clay, sub-clay, fine sand, fine porosity, the mineral components of rich fluoride provides an abundance of matter resources. The level to groundwater depth is shallow, capillary height of the zone of aeration is high, the water conductivity is low, multilayer mutual aquifer construct provide advantaged store water space for fluoride enrichment. Integrating hydrogeochemistry action, in order to reveal the regulation of fluoride flowing the groundwater path, studied the existence forms and percentum-densities of fluoride and the main complicated ions, at the same time, researched dissolution-precipitation problems of their mineral sources.