The impact of CO2 on shallow groundwater chemistry: observations at a natural analog site and implications for carbon sequestration

Journal Article · Tue Jan 01 04:00:00 EST 2008 · Environmental Geology

OSTI ID:960752

Keating, Elizabeth ^[1]; Fessenden, Julianna ^[1]; Kanjorski, Nancy ^[2]; Koning, Dan ^[3]; Pawar, Rajesh ^[1]

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1. Los Alamos National Laboratory
2. NON LANL
3. NM BUREAU OF GEOLOGY AND MINERAL RESOURCES

In a natural analog study of risks associated with carbon sequestration, impacts of CO{sub 2} on shallow groundwater quality have been measured in a sandstone aquifer in New Mexico, USA. Despite relatively high levels of dissolved CO{sub 2}, originating from depth and producing geysering at one well, pH depression and consequent trace element mobility are relatively minor effects due to the buffering capacity of the aquifer. However, local contamination due to influx of saline waters in a subset of wells is significant. Geochemical modeling of major ion concentrations suggests that high alkalinity and carbonate mineral dissolution buffers pH changes due to CO{sub 2} influx. Analysis oftrends in dissolved trace elements, chloride, and CO2 reveal no evidence of in-situ trace element mobilization. There is clear evidence, however, that As, U, and Pb are locally co-transported into the aquifer with CO{sub 2}-rich saline water. This study illustrates the role that local geochemical conditions will play in determining the effectiveness of monitoring strategies for CO{sub 2} leakage. For example, if buffering is significant, pH monitoring may not effectively detect CO2 leakage. This study also highlights potential complications that CO{sub 2}carrier fluids, such as saline waters, pose in monitoring impacts ofgeologic sequestration.

• Research Organization: Los Alamos National Laboratory (LANL)
• Sponsoring Organization: DOE
• DOE Contract Number: AC52-06NA25396
• OSTI ID: 960752
• Report Number(s): LA-UR-08-07070; LA-UR-08-7070
• Journal Information: Environmental Geology, Journal Name: Environmental Geology
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
ACID NEUTRALIZING CAPACITY
AQUIFERS
ARSENIC
BUFFERS
CARBON DIOXIDE
CARBON SEQUESTRATION
CARBONATE MINERALS
CHEMISTRY
CONTAMINATION
DEPTH
DISSOLUTION
FLUIDS
GROUND WATER
HAZARDS
IONS
LEAD
LEAKS
LEVELS
MOBILITY
MONITORING
NEW MEXICO
SANDSTONES
SIMULATION
TRACE AMOUNTS
URANIUM
WATER
WELLS