耀县幅地下水水化学特征及硝酸盐污染来源分析

发布时间：2018-02-17 06:32

本文关键词： 地下水水化学特征硝酸盐因子分析法土地利用方式　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：耀县幅位于陕西省铜川市东南部,近些年由于该地区社会经济的迅速发展,对地下水开发利用程度也日益加大,加之村民饮用水基本以地下水为主,所以研究该地区地下水的污染情况迫在眉睫。本文通过研究耀县幅地区的水文地质条件,结合地质地貌形态,先从大体上掌握该地区地下水的补径排条件;然后通过水化学分析,揭示了区域内地下水水中主要离子的变化特征,再根据水质报告对该地区的地下水进行等级分类,结合水化学特征初步判断造成污染的主导离子是硝酸根。最后运用因子分析法具体研究污染来源,再结合GIS技术,重点对区域内的硝酸盐进行污染源解析。得出主要结论如下:(1)研究区内不同水体水化学类型主要以HCO3-、Na+、Ca2+、Mg2+为主,占所有样点水化学类型的52%,其次为HCO3-、Na+和HCO3-、Na+、Mg2+型水,阳离子以Ca2+和Na+为主,阴离子以HCO3-为主。除了含水层岩性等自然作用外,人类活动尤其也是影响地下水水化学成分的重要因素,在该地区主要表现为农业活动。(2)根据各离子的检测结果,NO3-是超标最为严重的离子,其超标率为22.5%,而NH4+和NO2-基本未检出。由此可见NO3-为研究区内“三氮”污染的主要污染物。(3)采用因子分析法对Cl-、SO42-、HCO3-、Na+、Ca2+、Mg2+、PO43-、NO3-、F-共9种离子分析。最终得到三个公因子对方差贡献率较大,第一公因子为Ca2+、Mg2+、Cl-、SO42-、NO3-,综合了自然成分和农业化肥中的主要成分,体现了人类活动对天然地下水质的影响;第二公因子为Na+、HCO3-,是天然地下水中的常规组分,体现了自然作用对地下水水质的影响。第三公因子为PO43-,也主要来自农业施肥,体现了人类活动对地下水质的影响。(4)做出区内NO3-含量分布与土地利用类型叠加图,其中土地利用方式主要包括农田、城区、混合用地和未利用土地四种,结果显示农田的硝酸盐污染最为严重,其次是城区和混合类型土地。
[Abstract]:The Yaoxian area is located in the southeast of Tongchuan City, Shaanxi Province. In recent years, due to the rapid development of social economy in this area, the degree of exploitation and utilization of groundwater has also been increasing day by day. In addition, villagers' drinking water is basically dominated by groundwater. Therefore, it is urgent to study the groundwater pollution in this area. By studying the hydrogeological conditions in Yaoxian area and combining with the geological and geomorphological morphology, this paper first grasps the groundwater recharge and drainage conditions in general; Then, by means of hydrochemical analysis, the variation characteristics of the main ions in the groundwater in the area are revealed, and the groundwater in the area is classified according to the water quality report. Combined with the chemical characteristics of water, it is preliminarily judged that the dominant ion causing pollution is nitrate. Finally, the source of pollution is studied by factor analysis method, and then combined with GIS technology. The main conclusions are as follows: (1) the main hydrochemical types of different water bodies in the study area are mainly HCO _ 3-Na-Na _ 2 Ca _ 2 + mg _ 2, accounting for 52% of all the water chemical types, followed by HCO _ 3-N _ Na and H _ CO _ 3-Na-Na / mg _ 2 type water. The cations are mainly Ca2 and Na, and the anions are HCO3-. In addition to natural effects such as aquifer lithology, human activities are also important factors affecting the chemical composition of groundwater. In this area, the main manifestation is agricultural activity. (2) according to the results of each ion detection, no 3- is the most serious ion in excess of the standard. The rate of exceeding the standard was 22.5, while NH4 and NO2- were not detected. It can be seen that NO3- is the main pollutant of "three nitrogen" pollution in the study area. The factor analysis method was used to analyze nine kinds of ions of Cl-so _ 42-HCO _ 3-Na ~ (2 +) Ca ~ (2 +) O _ (4-O _ (3) O _ (3) O _ (3) O _ (3) O _ (-) -F-). Finally, the difference contribution rate of each other among the three common factors was obtained. The first common factor is Ca2 mg _ 2Cl-C _ 2SO _ 42-no _ 3-which synthesizes the natural composition and the main components of agricultural fertilizer, which reflects the influence of human activities on the natural underground water quality, and the second common factor is Na _ 2O _ 3, which is a conventional component of natural groundwater. The third common factor is PO43-which mainly comes from agricultural fertilization, which reflects the influence of human activities on groundwater quality. The results showed that the nitrate pollution in farmland was the most serious, followed by urban area and mixed land.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P641.3;X523

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