| Several geochemical changes may arise should geologically sequestered carbon dioxide migrate into an overlying potable aquifer. The objective of this research project was to identify the key short-term changes. This was achieved by conducting a leaching test, a pressurized column study, and geochemical modeling.; Elevated carbon dioxide levels introduced to the groundwater resulted in a reduced pH, despite the buffering effects of the carbonate minerals. Other geochemical changes were observed, including the solubilization and precipitation of various mineral phases present in the sediment. Elements most affected were calcium, magnesium, nickel, iron, strontium, and barium, all of which underwent net dissolution, increasing their concentration in the groundwater.; The elevated bicarbonate levels caused the groundwater to become oversaturated with respect to several carbonate minerals, allowing the formation of precipitates, such as siderite. These precipitates reduced the porosity of the sediment, resulting in a net decrease in hydraulic conductivity. |
