黑河流域地下水水化学特征分析化学专业.docx

Abstract 黑河流域地下水水化学特征分析 摘要 黑河流域是我国西北地区第二大内陆河流域，是我国主要的生态危急区之一，也是我国水资源稀缺地区，水环境急剧恶化已经严重影响区域可持续发展。本文通过分析黑河流域地下水主要阴离子（Cl-,SO42-,HCO3-，F-和NOx-）和主要阳离子（Na+,Ca2+,Mg2+及K+）的含量，运用相关性分析法、离子比值法、Piper图法及氯碱性指数法等研究方法对黑河流域地下水的水化学特征和地下水的离子交换效果分析，揭示黑河流域地下水的水化学主要离子的来源及其分布特征，从而为黑河流域地下水水质评价提供科学依据。主要结论如下： 1. 黑河上游地下水的pH值是7.4—8.3，上游的电导率（EC）的范围是5—3186µS/cm， TDS的范围是3—1752mg/L；；中游的pH值范围是6.2—9.4，EC的范围是256—12400µS/cm，TDS的范围是111—6160mg/L，；下游的pH值范围为5.6—9.3µS/cm， EC的范围是344—7592µS/cm， TDS的范围为118—5833mg/L，平均值为1136mg/L。可知中游和下游的pH、EC、TDS的含量变化范围大于上游，中游流域为平原，表明中游和下游受人类活动环境影响的程度较大。 2. Piper图结果表明黑河上游地下水水化学类型以HCO3- — Ca2+ ▪ Mg2+型、SO42- — Ca2+ ▪ Mg2+型为主，中游以SO42- ▪ HCO3- ▪ Cl- — Mg2+型、SO42- ▪ HCO3- ▪ Cl- — Mg2+型为主，下游以SO42- ▪ Cl- — Na+ ▪ Mg2+型为主，产生差异的原因可能是黑河流域地下水水化学组分的控制作用不同。 结合Gibbs图，黑河流域上游地下水的样品点落在水岩相互作用区域，中游和下游的样品点落在水岩作用和蒸发浓缩作用区域以及两个区域中间。说明黑河流域地下水上游水化学成分主要受水岩相互作用影响，中游和下游的水化学组分的形成是水岩相互作用和蒸发浓缩作用的双重影响产生的。 3. 氯碱性指数（CAI）的结果，若CAI1和CAI2均为正值，表明离子交换主要发生在高盐度的地下水中。如果为负值，表示氯-碱不平衡，发生阳离子-阴离子交换反应。本研究中黑河上游和中游的地下水的CAI1为负，CAI2为正，表明黑河中游和上游氯碱不平衡，发生了阴阳离子互相交换的反应；而黑河下游地下水的CAI1和CAI2均为正，表明黑河下游流域的离子交换作用也是影响地下水的水化学成分的一个重要机制。 4. 黑河流域中游流域的地下水中的F-的含量随深度的增加而降低的趋势，但是趋势并不明显；下游流域的地下水中F-的含量随着深度的增加有明显的增加趋势。其原因是黑河中游和下游区域蒸发作用强烈，地下水滞留时间较长，易于氟的富集。黑河流域上游区域的地下水中亚硝态氮的平均值为0.160mg/L，硝态氮平均值为2.261mg/L；中游的亚硝态氮的平均值为20.262mg/L，硝态氮的平均值为20.262mg/L；下游的亚硝态氮平均值为0.913mg/L，硝态氮的平均值为13.201mg/L。表明了亚硝态氮和硝态氮的含量在不同区域的关系：亚硝态氮的含量在黑河整个流域呈现如下关系：下游>上游≈中游；硝态氮在黑河流域的分布表现为：中游>下游>上游，说明了上游地下水的水质良好，中游和下游地下水的氮污染较为严重。 关键词：黑河流域，地下水，水化学特征，氯碱性指数，Gibbs图 Abstract The Heihe River Basin is the largest inland river basins in northwestern China and one of the major ecologically critical areas in China. In this paper, by using the correlation analysis, ion ratio method and Piper diagram analysis the main ions (Na+,Ca2+,Mg2+,K+，Cl-,SO42-,HCO3-，F-，NOx-) of groundwater in the Heihe River Basin and using the chlor-alkali index method analysis the ion exchange effect in the groundwater of the Heihe River Basin, revealed the source and distribution characteristics of the main hydrochemical ions of groundwater in the Heihe River Basin, thus providing a scientific basis for groundwater quality assessment in the Heihe River Basin. The main conclusions are as follows: 1. By Analysising the index ​​of pH, EC and TDS of groundwater in the upstream, midstream and downstream of Heihe River. It was found that the content of pH, EC and TDS in the middle and lower reaches was much larger than that in the upstream, and the variation range was very large. This indicated that the midstream and downstream were affected by the environment (including geological rock environment and artificial living environment) to a greater extent. 2. The water chemistry types in the upper reaches of the Heihe River were mainly HCO3- — Ca2+ ▪ Mg2+type、SO42- — Ca2+ ▪ Mg2+ type, the water chemistry type of groundwater in the middle reaches of the Heihe River were SO42- ▪ HCO3- ▪ Cl- — Mg2+type、SO42- ▪ HCO3- ▪ Cl- — Mg2+type, the water chemistry type of spring water samples downstream of the Heihe River is SO42- ▪ Cl- — Na+ ▪ Mg2+type. 3. According to Gibbs map, the water chemical composition in the upper reaches of the Heihe River Basin was mainly affected by the interaction of water and rock. The formation of hydrochemical components in the middle and lower reaches is caused by the dual effects of water-rock interaction and evaporation. 4. According to the chlor-alkali index, the chlor-alkali index was imbalance of groundwater in the upper and middle reaches of the Heihe River, it indicated that the exchange of anions and cations occured. The ion exchange in the lower reaches of the Heihe River is also an important mechanism affected the water chemical composition of groundwater, and indicates the lower reaches of the Heihe River, and the salinity of groundwater in the Heihe River basin is high. 5. The content of F- in groundwater in the middle reaches of the Heihe River Basin hsd the trend of decreasing with increasing depth, but the trend was not obvious. The content of F- in groundwater in the downstream basin has a significant trend of increasing with the increasing of depth. The content of fluorine in the Heihe River Basin is affected by climatic and hydrogeological conditions, pH, major ions of water chemistry, types of water chemistry and human production activities. 6. The relationship of the “trinitrogen” content among different regions: the content of nitrite nitrogen in the whole basin of Heihe had the following relationship: Downstream is greater than upstream is greater than midstream, where the gap of nitrite content in the upstream basin and middle reaches was not large; the distribution of nitrate nitrogen in the Heihe River Basin is: Midstream greater than downstream greater than upstream. Keywords: the Heihe River Basin, groundwater, hydrochemical characteristics, chloralkaline index, Gibbs diagram 51 目录 目 录 摘要 I 第一章 绪论 1 1.1 研究背景及意义 1 1.2 国内外研究进展 2 1.2.1 国外研究进展 2 1.2.2 国内研究现状