School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510006, PR China.
School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510006, PR China; School of geography and planning, Sun Yat-Sen University, Guangzhou 510006, PR China.
Sci Total Environ. 2020 Jul 1;724:137930. doi: 10.1016/j.scitotenv.2020.137930. Epub 2020 Mar 13.
A comprehensive understanding of the impacts of natural and human activities on groundwater evolution is critical for sustainable groundwater resource management, as groundwater quality degradation from urbanization has raised widespread concerns. However, conclusions based only on basic hydrochemical data would be fragmentary because complex processes occur with high concentrations of pollutants in rapidly urbanized areas. Thus, the hydrogeochemical and multi-isotope approaches were combined to elucidate the groundwater hydrogeochemical evolution in such an area. The results demonstrated that the major hydrochemical types of groundwater were ClNa and HCO-Ca in 2018 and that the hydrochemical patterns had changed since 1980. The predominant controlling factors for groundwater hydrochemistry were rock weathering due to carbonic, sulfuric and nitric acids, while the cation exchange and evaporation processes acted as natural factors; redox reactions, including denitrification, sulfate reduction, and methanogenesis, also affected groundwater hydrochemistry. The impacts of anthropogenic activities on groundwater hydrochemistry consisted of direct impacts that referred to the infiltration of manure and septic waste responsible for the occurrence of high NO content and part of the SO content in groundwater and indirect impacts that included the following issues: (1) acid rain accelerated water-rock interactions and resulted in the accumulation of SO; (2) sulfate reduction and methanogenesis increased the HCO content and expanded the distribution of HCO-type water; (3) organic matter associated with manure and septic waste accelerated the development of a reducing environment in groundwater; and (4) the occurrence of a strong reducing environment promoted the release of Mn, aggravated heavy metal pollution and imposed adverse effects on the ecological system.
全面了解自然和人为活动对地下水演化的影响，对于可持续的地下水资源管理至关重要，因为城市化导致的地下水质量退化已引起广泛关注。然而，仅基于基础水文化学数据得出的结论是不完整的，因为在快速城市化地区，存在高浓度污染物的复杂过程。因此，本研究结合水文地球化学和多同位素方法来阐明该地区的地下水水文地球化学演化。结果表明，2018 年地下水的主要水化学类型为 Cl-Na 和 HCO-Ca，自 1980 年以来，水化学模式发生了变化。地下水水化学的主要控制因素是碳酸、硫酸和硝酸作用下的岩石风化，阳离子交换和蒸发过程是自然因素；还原反应，包括反硝化、硫酸盐还原和产甲烷作用，也影响了地下水水化学。人为活动对地下水水化学的影响包括直接影响和间接影响：直接影响是指厩肥和化粪池废物的渗透，导致地下水 NO 含量高和部分 SO 含量的出现；间接影响包括以下几个方面：（1）酸雨加速了水-岩相互作用，导致 SO 的积累；（2）硫酸盐还原和产甲烷作用增加了 HCO 的含量，扩大了 HCO 型水的分布；（3）与厩肥和化粪池废物相关的有机物加速了地下水还原环境的发展；（4）强还原环境的出现促进了 Mn 的释放，加重了重金属污染，并对生态系统产生不利影响。
