摘要:
通过水文地质调查、水样采集,结合地下水流动系统、统计分析、吉布斯图、Piper三线图和相关性分析,对土默川平原地下水水化学特征进行研究.结果表明,该区地下水呈弱碱性,水化学类型以HCO3-Ca型和Cl-Na型为主.潜水水化学成分主要受水-岩相互作用和蒸发浓缩作用影响,承压水水化学成分主要受水-岩相互作用过程控制.79个潜水样品中方解石和白云石饱和指数小于0的分别为1个和5个,56个承压水样品中饱和指数小于0的均为20个.区域地下水的弱碱性环境、高Na+、低Ca2+为高氟水的形成提供了条件,受蒸发浓缩作用影响潜水高氟区主要分布于托克托县城以东地下水的滞留排泄区;受含水层介质的影响承压水高氟区主要分布于湖积台地区域.局部区域地下水的强还原环境,铁、锰氧化物和氢氧化物的还原性溶解以及HCO-3的竞争吸附是形成高砷水的重要原因,受哈素海湖相沉积物的影响潜水高砷区主要分布在哈素海—高泉营一带;受铁氧化物、氢氧化物还原性溶解及地下水径流条件的控制,承压水高砷区主要分布在平原中部大黑河沿岸.
Abstract:
Based on the hydrogeological investigation and sample collection and combined with the groundwater flow system, statistical analysis, Gibbs analysis, Piper diagram and correlation analysis, the authors investigated the hydrogeochemical characteristics of groundwater in the Tumochuan plain. The results show that the groundwater in this area is of weak alkalinity, and the groundwater chemistry is mainly of HCO3-Ca and Cl-Na type. The chemical composition of the unconfined water is mainly influenced by the water-rock interaction and the evaporation concentration. The chemical composition of the confined water is mainly controlled by the water-rock interaction. In 79 unconfined water samples, the saturation index of calcite and that of dolomite less than 0 are 1 and 5, respectively. In 56 confined water samples, the saturation index of calcite and that of dolomite less than 0 are both 20. The weakly alkaline environment of regional groundwater, high Na+ and low Ca2+ provide the conditions for the formation of high-fluorine water. Influenced by the evaporation and concentration, the high-fluorine unconfined water is mainly distributed in discharge area of groundwater in the east of Tuoketuo County. Influenced by the aquifer media, the high-fluorine confined water is mainly distributed in the lacustrine platform. The strongly reducing environment of local groundwater together with Fe, Mn oxides and hydroxides of the reductive dissolution as well as competitive adsorption of HCO- 3 is an important reason for the enrichment of arsenic in this area. Influenced by sediments in Hasu Lake, the high-arsenic unconfined water is mainly distributed in Hasu Lake and Gaoquanying. Under the control of Fe oxides and hydroxides of the reductive dissolution and groundwater flow conditions, the high-arsenic confined water is mainly distributed along the bank of Dahei River in the middle of the plain.
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