内蒙古托克托县潜水与土壤中氟化物的分布规律及其相关性研究

发布时间：2018-02-26 06:06

本文关键词： 地下水氟化物土壤可溶性氟水文地球化学托克托县　出处：《内蒙古大学》2015年硕士论文　论文类型：学位论文

【摘要】：地下水氟化物超标已经成为影响我国北方干旱半干旱地区饮用水安全的重要因素。其中,内蒙古自治区托克托县地下水中含有的过量氟化物,已经严重影响着当地居民的饮用水安全和社会经济的发展。本文结合水文地质学、地下水动力学及水文地球化学等理论,分析了研究区潜水和土壤中氟化物的分布特征及其赋存规律,并进一步探讨二者的相互作用和影响机理,主要得出以下结论：1.研究区潜水水化学类型主要为NaCl型,而混合CaHCO3型、混合CaMgCl型、CaCl型及NaHCO3型水均较少。研究区的这种水水化学分布主要是由于潜水位埋深较浅,地下水蒸发浓缩强烈,导致低溶解度Ca2+、Mg2+容易析出,而Na+和Cl-由于溶解度较高,因而成为了研究区潜水中的主要水化学成分。2.研究区地下水中氟含量与地下水其它化学组分的相关分析研究表明：对于潜水含水层,阳离子Ca2+与F-相关程度最高,呈显著性负相关,表明Ca2+浓度对潜水含水层中氟化物含量影响较大。3.研究区潜水氟的最小浓度为0.15 mg/L,最大浓度为7.00 mg/L,平均值为2.10mg/L。从总体上看,本区湖积台地地下水潜水氟含量比冲湖积平原高。在整个研究区域内大部分潜水中氟含量超出我国《地下水质量标准》GB/T14848-1993中Ⅲ水水质所规定的1.0mg/L上限,表明潜水水质在一定程度上已产生氟污染,已经不宜作为生活饮用水水源。4.研究区地下水中氟与土壤水溶性氟的空间浓度分布特征具有较高的相似性,都表现出东高西低的趋势；最高值都集中在冲湖积平原及湖积台地中部,最低值都出现在大黑河与黄河沿岸及大黑河以西一带。研究区东部的蛮汉山为该区地下水的主要补给区,自第三纪以来经历了至少四次玄武岩喷发,大量的富氟矿物在漫长的地质演化、风化及水岩相互作用下被带入带湖积台地内沉积,从而成为土壤和地下水中氟化物的重要来源。此外,在冲湖积平原与湖积台地之间的沟谷地带,地势低洼、水动力条件差、加之地下水位埋深较浅,蒸发作用的影响强烈,进一步促进了地下水中氟化物富集。
[Abstract]:The excess fluoride in groundwater has become an important factor affecting the safety of drinking water in arid and semi-arid areas of northern China. This paper combines the theories of hydrogeology, groundwater dynamics, hydrogeochemistry and so on. The distribution and occurrence of fluoride in phreatic water and soil in the study area were analyzed, and their interaction and influence mechanism were discussed. The main conclusions were as follows: 1. The chemical types of diving water in the study area were mainly NaCl type, while mixed CaHCO3 type. The chemical distribution of this water in the study area is mainly due to the shallow buried depth of groundwater and the strong evaporation concentration of groundwater, which results in the easy precipitation of Ca2 Mg2 with low solubility, and the high solubility of Na and Cl- in the study area. Therefore, it has become the main chemical component of groundwater in the study area. 2. The correlation analysis of fluorine content in groundwater and other chemical components of groundwater in the study area shows that the correlation degree between cation Ca2 and F- is the highest for the diving aquifer. There was a significant negative correlation between Ca2 concentration and fluoride content in the aquifer. 3. The minimum concentration of fluoride was 0.15 mg / L, the maximum concentration was 7.00 mg / L, and the average value was 2.10 mg / L. The fluoride content of groundwater in the lake platform is higher than that in the alluvial plain. The fluoride content in most of the phreatic water in the whole study area exceeds the limit of 1.0 mg / L specified in the third water quality of GB/T14848-1993 in China. The results show that the groundwater quality has produced fluoride pollution to a certain extent, and it is not suitable to be used as a drinking water source. 4. The spatial distribution characteristics of fluorine in groundwater and soil water-soluble fluoride in the study area have high similarity. The highest values are concentrated in the alluvial plain and the middle of the lacustrine platform. The lowest values occur along the Dahei River and the Yellow River and to the west of the Dahei River. The Mannghan Mountains in the eastern part of the study area are the main recharge areas for groundwater in this area, and have experienced at least four basalt eruptions since the Tertiary. A large number of fluorine-rich minerals have been brought into the lacustrine terraces during the long geological evolution, weathering and water-rock interaction, thus becoming an important source of fluoride in soil and groundwater. In the gully zone between the alluvial lake plain and the lacustrine platform, the topography is low, the hydrodynamic condition is poor, the groundwater level is shallow, and the influence of evaporation is strong, which further promotes the enrichment of fluoride in groundwater.
【学位授予单位】：内蒙古大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X523

【参考文献】