Geochemical Impacts to Groundwater from Geologic Carbon Sequestration: Controls on pH and Inorganic Carbon Concentrations from Reaction Path and Kinetic Modeling
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- 作者：Richard T. Wilkin ; Dominic C. DiGiulio
- 刊名：Environmental Science & Technology
- 出版年：2010
- 出版时间：June 15, 2010
- 年：2010
- 卷：44
- 期：12
- 页码：4821-4827
- 全文大小：261K
- 年卷期：v.44,no.12(June 15, 2010)
- ISSN：1520-5851
文摘
Geologic carbon sequestration has the potential to cause long-term reductions in global emissions of carbon dioxide to the atmosphere. Safe and effective application of carbon sequestration technology requires an understanding of the potential risks to the quality of underground sources of drinking water. In particular, concern is warranted regarding the potential for CO2 leakage through geological features and abandoned wells that may result in detrimental perturbations to subsurface geochemistry. Reaction path and kinetic models indicate that geochemical shifts caused by CO2 leakage are closely linked to mineralogical properties of the receiving aquifer. CO2 gas dissolution into groundwater and subsequent reaction with aquifer minerals will control the evolution of pH−bicarbonate envelopes. These parameters provide geochemical context for predicting how regulated contaminants associated with aquifer solids will respond via various mineral−water reaction processes. The distribution and abundance of carbonate, silicate, oxide, and phyllosilicate minerals are identified as key variables in controlling changes in groundwater geochemistry. Site-specific risk assessments may require characterization of aquifer geology, mineralogy, and groundwater chemistry prior to CO2 injection. Model results also provide a frame of reference for developing indicative measurement, monitoring, and verification (MMV) protocols for groundwater protection.