【作者】 龙文华；

【导师】 陈鸿汉；

【作者基本信息】 中国地质大学（北京） ， 环境科学与工程， 2010， 博士

【摘要】 随着地下水开采,通辽市城区附近浅层地下水中出现TDS和总硬度超标现象,威胁到了当地生产及生活用水安全。因此,本文以“西辽河平原地下水资源及其环境问题调查评价”项目为支撑,综合应用水文地质学、水文地球化学、水文地球化学模拟的理论与方法,对通辽市城区附近浅层地下水化学成分的时空演变规律进行了深入的研究。研究区第四系浅层含水层（80m以上）主要岩性为中细砂、细砂、粉砂和泥质细砂组成。地下水以大气降水和侧向径流补给为主,水质总体较好,多数为良好级别以上的水,水化学类型以HCO₃-Ca、HCO₃-Ca·Mg为主,部分为较差级别水,市区附近出现HCO₃·SO₄-Ca·Mg、HCO₃-Ca·Na及HCO₃-Na·Ca型水。TDS均小于lg/L,大部分地区浅层地下水为微硬水。通辽市城区降落漏斗中心附近,TDS含量较高,最高为962.99mg/L,这里出现了一些极硬水。水化学演化分析结果表明TDS和总硬度总体上呈增加趋势,在通辽市城区东部增加最快。到2003年,TDS增加了662.99mg/L,硬水分布面积达1427.8km2,极硬水超过100km2。沿地下水流向,文石、方解石和白云石的饱和指数从小于0到大于0呈递增的变化趋势,由不饱和逐渐变为饱和。水文地球化学模拟显示地下水径流过程中发生了方解石、白云石、文石、盐岩、石膏和二氧化碳的溶解,以及钙离子的吸附和钠离子解析,使得浅层地下水的TDS和总硬度增加。影响和决定研究区浅层地下水化学成分形成及演化规律的因素主要包括水—岩相互作用和人类活动因素的影响。①溶解沉淀作用、阳离子交换吸附作用、蒸发浓缩作用共同决定了研究区浅层地下水化学成分的形成特征；②地下水超量开采,水位持续下降,改变了地下水运动的流场,原饱水带变为包气带,还原环境转化为氧化环境,同时增加了大气降水等垂直入渗补给途径,加大了对Ca2+、Mg²+、Na^、Cl等离子的淋滤过程,直接影响了浅层地下水TDS和总硬度的含量；③农业灌溉的不正确施肥、在城镇周围生活垃圾及工业废渣的随意堆放及渗井、渗坑的存在等人为污染直接导致浅层地下水受到严重污染。更多还原

【Abstract】 With the development of groundwater, The TDS and total hardness of the shallow groundwater exceed the standard near Tongliao City, which threats the safety of domestic and industrial water usage. Therefore, supported by the project of "Assessment of groundwater resource and its environmental problems in Xiliao River Plain", this dissertation focused on the in depth study on the spatial-temporal evolution of shallow groundwater chemical characteristics in Tongliao City, which integrated the theories and methodologies of hydrogeology, hydro-geochemistry, and hydrogeochemical simulation.The study area focus on the Quaternary shallow groundwater aquifer （with thickness of more than 80m）, which mainly consists of medium-find sand, fine sand, silty sand, and shaly fine sand. Precipitation and lateral flow are the main recharge of the groundwater. In general, the groundwater quality was relatively good, most of which can be classified into the standard of good or better. The major hydrochemical type of groundwater is HCO₃-Ca and HCO₃-Ca·Mg. Groundwater with relatively poor quality existed in some parts. Close to the city, groundwater exhibited the hydrochemical type of HCO₃·SO₄-Ca’Mg, HCO₃-Ca·Na and HCO₃-Na·Ca. Overall, TDS was less than lg/L and most part of the region possessed the relative hard water. Near the depression cone in the Tongliao City, TDS was higher, which ranged up to 962.99mg/L, with extremely hard water occurred. Based on the analysis of evolution of groundwater chemicals, TDS and Hardness tended to increase, which increased greatly in the suburbs in Tongliao City. By 2003, TDS increased 662.99mg/L, the area covered by hard water reached to 1427.8 km², while the extremely hard water covered an area of over 100 km².Along the flow direction, saturation index of aragonite, calcite and dolomite increased from less than zero to larger than zero, which means they changed from unsaturation to saturation gradually. The hydrogeochemical simulation indicated that the increase in TDS and total hardness resulted from the dissolving of aragonite, calcite, dolomite, halite, gypsum and C02（g） dissolved into shallow groundwater, which caused TDS and hardness increasing, as well as the adsorption of calcium ion and dissociative of sodium ion during the groundwater flow process..The major factors that affected the formation and evolution of shallow groundwater chemical characteristics are water-rock interaction and human activities.①the formation of shallow groundwater chemical characteristics depended on the processes of dissolution-precipitation, cation exchange and absorption, as well as evaporation and concentration;②over-development of groundwater and decreasing of groundwater table changed the flow path of groundwater, so that the saturated zone became vadose zone, and the reduction environment changed to oxidation. In addition, vertical recharge increased such as precipitation, which enhanced the eluviations of ions such as Ca²⁺, Mg²⁺, Na⁺and C1, resulting directly in the TDS and total hardness of groundwater.③Human activities such as incorrect fertilization in agricultural irrigation, randomly stacking of domestic wastes and industrial wastes around the city, and the existing of leakage wells and pits directly and severely polluted the groundwater.更多还原