Assessing the health risks of natural CO2 seeps in Italy

Industrialised societies which continue to use fossil fuel energy sources are considering adopting C capture and storage (CCS) technology to meet C emission reduction targets. Deep inshore geological storage of CO2 faces opposition regarding potential health effects of CO2 leakage from storage sites. There is no common scale CCS experience with which to verify predicted risks of engineered storage failure. Examining risk from natural CO2 seeps can guide assessment of potential health risks from leaking onshore CO2 stores. Italy and Sicily are regions of intense natural CO2 degassing from surface seeps which exhibit a variety of expressions, characteristics (e.g., temperature/flux), and location environments. This study quantified historical fatalities from CO2 poisoning using a database of 286 natural CO2 seeps in Italy and Sicily. Human death risk was strongly affected by seep surface expression, local conditions (e.g., topography, wind speed), CO2 flux, and human behaviour. Accidental human death risk from these CO2 seeps was calculated to be 10-8 yr-1 to the exposed population. This value is significantly lower than that of many socially accepted risks. Seepage from future storage sites was modelled to be less that Italian natural flux rates. The authors concluded that with appropriate hazard management, health risks from unplanned seepage at onshore storage sites can be adequately minimised.

Authors: Roberts, Jennifer J.; Wood, Rachel A.; Haszeldine, R. Stuart ;Full Source: Proceedings of the National Academy of Sciences of the United States of America 2011, 108(40), 16545-16548, S16545/1-S16545/9 (Eng) ;