A new study has revealed that leakage of carbon dioxide injected deep underground to help fight climate change could turn up in drinking water aquifers near the surface, driving up levels of contaminants in the water tenfold or more in some places.
“We found the potential for contamination is real, but there are ways to avoid or reduce the risk,” said Robert B Jackson at Duke University.
“Geologic criteria that we identified in the study can help identify locations around the country that should be monitored or avoided. By no means would all sites be susceptible to problems of water quality,” he said.
Storing carbon dioxide deep below Earth’s surface, a process known as geosequestration, is part of a suite of new carbon capture and storage (CCS) technologies being developed by governments and industries worldwide to reduce the amount of greenhouse gas emissions entering Earth’s atmosphere.
It is designed to capture and compress CO2, emissions at their source, typically power plants and other industrial facilities, and transport the CO2 to locations where it can be injected far below the Earth’s surface for long-term storage.
After a year’s exposure to the CO2, analysis of the samples showed that “there are a number of potential sites where CO2 leaks drive contaminants up tenfold or more, in some cases to levels above the maximum contaminant loads set by the EPA for potable water,” Jackson said.
“Along with changes in carbonate concentration and acidity of the water, concentrations of manganese, iron and calcium could all be used as geochemical markers of a leak, as their concentration increase within two weeks of exposure to CO2,” Jackson said.
The study appears in the online edition of the journal of Environmental Science & Technology.
