Carbon capture and storage could contaminate drinking water

Industrial pipework

Instead of dumping carbon deep underground we could be exploring ways to re-use it, such as in producing hydrocarbons or algae

Capturing and then burying carbon dioxide deep underground in a bid to reduce emissions may lead to a contamination of water aquifers

Government-supported plans to bury the carbon produced by power stations underground - to reduce greenhouse gas emissions - could contaminate our water supplies, suggests a study.

With fossil fuel-burning power stations continuing to be built rather than closed down there has been recent focus on technologies that capture and store the carbon pollution produced. So-called carbon capture and storage (CCS) sees captured carbon compressed into a liquid, so that it takes up less space, and then potentially buried deep underground.

Although no commercial plants are yet in operation the US, UK and EU Commission are planning to fund both coal and gas plants demonstrating the technology. The International Energy Association (IEA) estimated that after 2020, 98 per cent of new coal power plants would be built with CCS capability.

However, the study by scientists from Duke University in the US found that leaks from carbon dioxide buried underground could bubble into drinking water aquifers near the surface and drive up contaminants in the water by ten times or more and above environmental limits. They collected core samples from freshwater aquifers in the US that overlie potential CCS sites and then studied their reaction to exposure to CO2 over the course of a year in the laboratory.

'The fear of drinking water contamination from CO2 leaks is one of several sticking points about CCS and has contributed to local opposition to it,' said study author Professor Robert Jackson. 'We examined the idea that if CO2 leaked out slowly from deep formations, where might it negatively impact freshwater aquifers near the surface, and why.'

Jackson said they had identified markers, including changes in carbonate concentration and acidity of the water, concentrations of manganese, iron and calcium which could all be used as early warnings of CO2 leaks.

A spokesperson for the department for energy and climate change in the UK said any potential storage of CO2 underground would be monitored closely by the Environment Agency to avoid possible contamination issues.

In Fixing Climate, the authors Robert Kunzig and Wallace Broecker estimate that a year of the world's fossil fuel emissions, if liquified and stored, would bury Manhattan Island to the 85th floor of the Empire State Building.

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