This study evaluated the effects of CO2 leakage on the geochemical composition of groundwater in various geological media through long-term column experiments. Four columns were set up with soil representing a silicate aquifer; clean sand; a sand and limestone mixture; and alluvium soil, respectively. The experiments were conducted under the same experimental conditions for approximately one year. As the CO2-saturated synthetic groundwater was introduced into the columns, a decrease in pH and increases in electrical conductivity (EC), alkalinity, and concentrations of cations and trace elements were observed in all geological media. However, different patterns of changes were also observed depending on the mineralogical and physico-chemical characteristics of each material. As the column operation continued, while the pH decreased and low alkalinity values were more evident in the silicate soil and clean sand columns, the carbonate column continued to show high alkalinity and EC values in addition to high concentrations of most cations. The alluvium soil showed distinctive cation-exchange behaviors during the initial introduction of CO2. The results indicate that changes in the geochemical composition of groundwater will depend on the characteristic of the geological medium such as pH buffering capacity and cation exchange capacity. This study can be useful for monitoring and managing the impacts of CO2 leakage in various aquifer environments.

中文翻译：

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不同地质介质中CO2泄漏引起地下水地球化学成分的变化

本研究通过长期柱状实验评估了 CO2 泄漏对各种地质介质中地下水地球化学成分的影响。用代表硅酸盐含水层的土壤设置了四根柱子；干净的沙子；沙子和石灰石的混合物；和冲积土，分别。实验在相同的实验条件下进行了大约一年。随着 CO2 饱和合成地下水被引入柱中，在所有地质介质中都观察到 pH 值降低，电导率 (EC)、碱度以及阳离子和微量元素浓度升高。然而，根据每种材料的矿物学和物理化学特性，也观察到了不同的变化模式。随着列操作的继续，虽然在硅酸盐土壤和干净的沙柱中 pH 值下降和低碱度值更明显，但碳酸盐柱除了大多数阳离子浓度高外，继续显示高碱度和 EC 值。在最初引入 CO2 期间，冲积土表现出独特的阳离子交换行为。结果表明，地下水地球化学成分的变化将取决于地质介质的特性，如pH缓冲能力和阳离子交换能力。这项研究可用于监测和管理各种含水层环境中 CO2 泄漏的影响。在最初引入 CO2 期间，冲积土表现出独特的阳离子交换行为。结果表明，地下水地球化学成分的变化将取决于地质介质的特性，如pH缓冲能力和阳离子交换能力。这项研究可用于监测和管理各种含水层环境中 CO2 泄漏的影响。在最初引入 CO2 期间，冲积土表现出独特的阳离子交换行为。结果表明，地下水地球化学成分的变化将取决于地质介质的特性，如pH缓冲能力和阳离子交换能力。这项研究可用于监测和管理各种含水层环境中 CO2 泄漏的影响。