Potential Impacts of CO2 Leakage on Groundwater Chemistry from Laboratory Batch Experiments and Field Push鈥損ull Tests
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- 作者：Patrick J. Mickler ; Changbing Yang ; Bridget R. Scanlon ; Robert Reedy ; Jiemin Lu
- 刊名：Environmental Science & Technology
- 出版年：2013
- 出版时间：September 17, 2013
- 年：2013
- 卷：47
- 期：18
- 页码：10694-10702
- 全文大小：331K
- 年卷期：v.47,no.18(September 17, 2013)
- ISSN：1520-5851
文摘
Storage of CO2 in deep saline reservoirs has been proposed to mitigate anthropogenically forced climate change. If injected CO2 unexpectedly migrates upward in shallow groundwater resources, potable groundwater may be negatively affected. This study examines the effects of an increase in pCO2 (partial pressure of CO2) on groundwater chemistry in a siliclastic-dominated aquifer by comparing a laboratory batch experiment and a field single-well push鈥損ull test on the same aquifer sediment and groundwater.
Although the aquifer mineralogy is predominately siliclastic, carbonate dissolution is the primary geochemical reaction. In the batch experiment, Ca concentrations increase until calcite saturation is reached at 500 h. The concentrations of the elements Ca, Mg, Sr, Ba, Mn, and U are controlled by carbonate dissolution. Silicate dissolution controls Si and K concentrations and is 2 orders of magnitude slower than carbonate dissolution. Changing pH conditions through the experiment initially mobilize Mo, V, Zn, Se, and Cd; sorption reactions later remove these elements from solution and concentrations drop to pre-experiment levels. The EPA鈥檚 primary and secondary MCL鈥檚 are not exceeded except for Mn, which exceeded the EPA鈥檚 secondary standard of 0.05 mg/L. Push鈥損ull results also identify carbonate and silicate dissolution reactions 2 orders of magnitude slower than batch experiments.
Although the aquifer mineralogy is predominately siliclastic, carbonate dissolution is the primary geochemical reaction. In the batch experiment, Ca concentrations increase until calcite saturation is reached at 500 h. The concentrations of the elements Ca, Mg, Sr, Ba, Mn, and U are controlled by carbonate dissolution. Silicate dissolution controls Si and K concentrations and is 2 orders of magnitude slower than carbonate dissolution. Changing pH conditions through the experiment initially mobilize Mo, V, Zn, Se, and Cd; sorption reactions later remove these elements from solution and concentrations drop to pre-experiment levels. The EPA鈥檚 primary and secondary MCL鈥檚 are not exceeded except for Mn, which exceeded the EPA鈥檚 secondary standard of 0.05 mg/L. Push鈥損ull results also identify carbonate and silicate dissolution reactions 2 orders of magnitude slower than batch experiments.