Potential impacts of CO ₂ leakage on groundwater quality of overlying aquifer at geological carbon sequestration sites: A review and a proposed assessment procedure

One of the risks geologic carbon sequestration (GCS) is leakage injected CO2 into overlying groundwater resources, resulting in potential deterioration quality due to increase acidity, release trace metals and organic compounds, changes microbial activities. A large number studies have been conducted evaluate various aspects impact on aquifers using natural analog, laboratory experiments, field tests, numerical models. In this paper, we an exhaustive review published work, focusing statistical assessment risk posed by elements including Pb, As, Cd, Ba, U identifying knowledge gaps. Key observations from include following: (1) are primary concern because multiple cases showed their concentration higher than maximum contaminant level (MCL) or other regulatory standards, (2) carbonate seemed more vulnerable Pb As contamination but not U, (3) Cd Ba less a concern, only one case Cd/Ba MCL, (4) none concentrations although push–pull test (5) order aggressiveness terms releasing was determined be as follows: batch experiment > column test, (6) there no clear correlation between metal type sediments, aquifer, content clay. Evaluation likely has done case-by-case basis. For further operations storage overview screening sites, suggest use eight-step environmental procedure comprising experiment, modeling testing for assessing vulnerability degradation GCS site. © 2021 Society Chemical Industry John Wiley & Sons, Ltd.