河套平原地下水化学特征研究

发布时间：2018-02-15 22:15

  本文关键词： 河套平原 地下水化学 高砷地下水 高铁地下水 高氟地下水　出处：《中国地质大学(北京)》2015年博士论文　论文类型：学位论文

【摘要】：本文详细总结了全球及河套平原地下水砷研究状况,以及砷在自然环境中的分布与富集规律。以河套平原为研究区,在深入分析研究地质构造、水文地质条件、地下水流场、补给径流条件的基础上,依据800余组地下水、地表水样品和岩土样品测试数据,对地下水的主要物理化学指标如:p H、ORP、矿化度、Cl-、SO42-、HCO3-、总砷As、总铁Fe、总磷P、F-等进行了详细的分析研究,刻画了各组分(指标)的区域分布和超标状况,同时进行了水环境分区,研究了水化学类型特征以及各测试指标内在相关性等。在上述研究的基础上,重点论述了As、Fe、F等超标组分的成因机制。主要结论如下:1.通过详细调查研究,查明了河套平原(13000 km2)地下水水化学特征和主要超标组分超标率、分布范围。1)河套平原属于典型的干旱半干旱地区,地下水化学特征主要表现为以碱金属-非重碳酸型为主(占49.29%)为主,其次是碱金属-重碳酸型(占29.76%)和碱土金属-重碳酸型(占16.06%),碱土金属-非重碳酸型较少(占4.88%);2)主要超标组分为As、Fe、Cl-、F-、SO42-、NO3-、总硬度,超标率分别是28.80%(As≥0.05mg/L)、61.56%、52.71%、20.74%、55.21%、2.50%;3)高砷地下水在平原西部以条带状分布在山前低洼地带;在中东部,呈不规则的面状或片状分布,覆盖范围较广,砷含量短距离内变化大,垂向上(80m以浅)随深度有增大趋势;高铁水主要分布在平原中部的冲湖积平原,地势低洼地带和地下水的排泄地带含量最高,高氟水主要以条带状分布在山前的冲洪积扇地带。2.通过多元统计分析,查明了河套平原的地下水化学组分的相关性特征。在全区及西部高砷区,As与P、Fe、F-和p H均呈显著的正相关关系。As与ORP、SO42-呈显著的负相关关系;F-与Ca2+显著负相关,F-与p H值显著正相关。3.通过对主要超标组分成因机理研究,查明了:1)地下水中的砷主要来源于第四纪沉积物和断裂运移的深部地下水;2)高铁地下水主要来源于由黄河携带来的大量的第四系沉积物,其溶出的主要原因是地下氧化还原条件的变化;3)高F地下水主要来源于平原周边的山区,气候、地质构造、水文地质和水化学条件是氟富集的主要因素。
[Abstract]:This paper summarizes in detail the research status of arsenic in groundwater of the whole world and Hetao Plain, as well as the distribution and enrichment of arsenic in the natural environment. Taking Hetao Plain as the study area, the geological structure, hydrogeological conditions and groundwater flow field are studied in depth. On the basis of recharge runoff conditions, based on the test data of more than 800 groups of groundwater, surface water samples and rock and soil samples, the main physical and chemical indexes of groundwater, such as: 1 / p HP ORP, Cl-so _ 4 _ 2-HCO _ 3-, total arsenic, total iron and Fe, total phosphorus Pf- and so on, are analyzed and studied in detail. The regional distribution and exceeding standard of each component (index) are described. At the same time, the water environment zoning is carried out, and the characteristics of hydrochemical type and the inherent correlation of each test index are studied. On the basis of the above research, The main conclusions are as follows: 1. Through detailed investigation and study, the chemical characteristics of groundwater in Hetao Plain (13000 km ~ 2) and the rate of exceeding the standard of main components are found out. (1) the Hetao Plain is a typical arid and semi-arid area, and the chemical characteristics of groundwater are mainly alkaline metal-non-bicarbonate type (49.29%). Secondly, alkali metal-bicarbonate type (29.76%), alkali earth metal-bicarbonate type (16.06%), alkaline-non-bicarbonate type (4.88%) mainly exceeded the standard, and the total hardness, The rates of exceeding the standard are 28.80mg / L ~ (-1) as 鈮，

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