地表补源水对地下水的水质影响机制研究

Aiming at the serious problem of the continuous decline of groundwater table caused by over-exploitation of groundwater, Jinan and other cities have taken artificial measures to inject surface water or other source water underground for groundwater recharge. In addition to the responsibility of spring protection, citizens in Jinan also cherish the aspiration for high quality drinkable groundwater, but the organic pollution and other risks existing in the micro-polluted source water are likely to be introduced into the groundwater system, which may bring a series of safety issues on water supply. Based on the concrete situation of the groundwater recharge project by surface water conversion in Jinan, the dynamic monitoring and research of recharged water and groundwater quality were carried out in this study. Combined with the historical water quality characteristics of the recharged water and groundwater, the critical parameters of water quality were established. Characteristics of dissolved organic matter (DOM) from the water source in Jinan and corresponding DBPs formation potential (DBPFP) were investigated. Raw waters were fractionated based on molecular weight and hydrophobicity. Particularly, structure variation and subsequent DBPFP of groundwater during recharge process were correlated. The mechanism of groundwater quality change during recharge process was discussed. Results of these studies enriched the pollution control theory system of groundwater recharge project by surface water conversion, providing a scientific foundation and theoretical basis for effectively controlling the health risk of groundwater that may occur in the recharge process by micro-polluted source water supplement.

针对地下水超采导致的地下水位持续下降的严峻问题，济南等城市采用人工措施将地表水或其他水源水注入地下以补充地下水，而济南市不仅有保泉的重任，市民还有饮用优质地下水的美好愿望，但微污染水源水存在的有机污染风险等有可能引入地下水系统，由此可能带来一系列的供水安全问题。本研究结合济南市地表水转换地下水补源工程实施的具体情况，开展地表补源水和地下水水质动态监测与研究，结合地表补源水和地下水的历史水质特征，识别济南地表水转换地下水补源工程关键水质指标；通过研究地表补源水中DOM不同性质组分对地下水消毒副产物生成能力的影响，揭示补源过程中消毒副产物前驱体的结构、形态转化与消毒副产物生成势的相关关系，探讨地下水的水质变化机制，丰富地表水转换地下水补源工程的污染控制理论体系，为有效控制微污染水源水回灌补源过程中可能对岩溶地下水带来的水质健康风险，提供科学依据和理论基础。

如何识别济南市地表水转换地下水补源工程在饮用水水质安全方面的关键指标，研究补源过程中地下水的水质变化机制，对于降低地表水回灌补源过程中可能引入的水质安全风险，具有重要的意义。本项目揭示了济南地表补源水与地下水水质的历史特征，结合地表补源水和地下水水质动态监测与研究，对济南地表补源水、地下水、泉水的主要水质指标建立了PCA降维识别方法，识别了济南市地表水转换地下水补源工程在水质安全上的关键指标。重点对玉符河地表水及其沿岸地下水水样进行了跟踪监测分析，结果表明现阶段人工补源工程尚未对地下水水质特征产生明显改变，但补源水水质变差、水量增大可能会对地下水水质带来不可逆转的改变，为今后评估人工补源工程的累积污染风险和长期实施的可行性提供了研究基础。揭示了地表水补源过程中消毒副产物前驱体的结构、形态转化与消毒副产物生成势的变化规律和机理，回灌补源增加了地下水中亲水性（Hi）和过渡性（Hs）组分的占比，增加了地下水色氨酸类蛋白质和溶解性微生物代谢产物升高的风险。补源后地下水Hi组分单位TOC生成消毒副产物的能力较强，尤其卤乙酸生成能力提高较为明显；阐明了消毒副产物前驱体结构形态与消毒副产物能力及种类的匹配关系，Hi组分生成卤乙酸的能力相对较强，主要存在较多的羧基和醇羟基结构；疏水性（Ho）和Hs组分生成三卤甲烷的能力相对较强，Ho组分存在较多的酚羟基、羰基和碳碳共轭双键结构，Hs组分包含更多的氨基结构。研究揭示了地表水回灌补源过程中，地下水的水质变化机制，为有效控制微污染水源水可能引入地下水的健康安全隐患提供科学基础。