Do we need a backup plan for the backup plan?

A newly released article raises some serious questions about storing CO2 underground in geological formations. The study involved the injection of CO2 into a brine and oil reservoir on the US Gulf Coast. It turns out that the CO2 made the brine water much more acidic, which means that minerals are much more easily dissolved, and the integrity of the reservoir could ultimately be compromised.

From the abstract:

"This rapid dissolution of carbonate and other minerals could ultimately create pathways in the rock seals or well cements for CO2 and brine leakage. Dissolution of minerals, especially iron oxyhydroxides, could mobilize toxic trace metals and, where residual oil or suitable organics are present, the injected CO2 could also mobilize toxic organic compounds. Environmental impacts could be major if large brine volumes with mobilized toxic metals and organics migrated into potable groundwater."

A more general explanation can be found here.

[via Treehugger]