中文摘要：

基于2006－2007年对研究区野外实地调研和水化学数据的测试分析，以国家地下水质量I类水标准为基值，筛选出12个超标的水化学组分，利用模糊灰色评价方法对地下水环境质量作出评价。结果表明，大荔县地下水绝大部分为5类水．并用熵权赋权法研究导致水质变差的主要水化学组分。结果表明，铁在该区影响最大，其次为氯化物、总硬度、氟化物、溶解性总固体，为苦咸水之源。含水层中铁、总硬度、溶鹪性总固体、硫酸根、卤化物区域性高含量主要由于大荔县特殊的气候、地质背景条件等所决定。而COD、硝酸盐、亚硝酸盐、锰、铬含量的增高由人类活动所为。

英文摘要：

In order to evaluate the groundwater quality and pollution in Dali county, we carried out the field survey and analysis of the water chemistry from 2006 to 2007. Based on the indexes for third-grade water of the Nnational groundwater quality standard of China, we selected 12 hydro-chemical components which exceed the standard to assess the groundwater environment quality using the fuzzy-grey evaluation model. The result shows that the majority of water fall the V type. Further study indicates that the factors affecting water quality are, from great to small, oxide of iron, chloride, total hardness, fluoride, total dissolved solid, which are the source of bitter salt water. The high contents of oxide of iron, total hardness, total dissolved solid, sulfate, halid are determined by geological condition and climate of Dali county, while that of COD, nitrate, nitrite, manganese, and chrome pollutant are mainly caused by human behaviors.