Effect of Dissolved CO2 on a Shallow Groundwater System: A Controlled Release Field Experiment

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• 作者：Robert C. Trautz ; John D. Pugh ; Charuleka Varadharajan ; Liange Zheng ; Marco Bianchi ; Peter S. Nico ; Nicolas F. Spycher ; Dennis L. Newell ; Richard A. Esposito ; Yuxin Wu ; Baptiste Dafflon ; Susan S. Hubbard ; Jens T. Birkholzer
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：January 2, 2013
• 年：2013
• 卷：47
• 期：1
• 页码：298-305
• 全文大小：379K
• 年卷期：v.47,no.1(January 2, 2013)
• ISSN：1520-5851

文摘

Capturing carbon dioxide (CO₂) emissions from industrial sources and injecting the emissions deep underground in geologic formations is one method being considered to control CO₂ concentrations in the atmosphere. Sequestering CO₂ underground has its own set of environmental risks, including the potential migration of CO₂ out of the storage reservoir and resulting acidification and release of trace constituents in shallow groundwater. A field study involving the controlled release of groundwater containing dissolved CO₂ was initiated to investigate potential groundwater impacts. Dissolution of CO₂ in the groundwater resulted in a sustained and easily detected decrease of 3 pH units. Several trace constituents, including As and Pb, remained below their respective detections limits and/or at background levels. Other constituents (Ba, Ca, Cr, Sr, Mg, Mn, and Fe) displayed a pulse response, consisting of an initial increase in concentration followed by either a return to background levels or slightly greater than background. This suggests a fast-release mechanism (desorption, exchange, and/or fast dissolution of small finite amounts of metals) concomitant in some cases with a slower release potentially involving different solid phases or mechanisms. Inorganic constituents regulated by the U.S. Environmental Protection Agency remained below their respective maximum contaminant levels throughout the experiment.