integrated approach to determine sediment quality in areas above CO₂ injection and storage in agreement with the requirements of the international conventions on the protection of the marine environment

The urgent need to reduce the greenhouse emissions to the atmosphere has leaded to study new systems to capture and store carbon dioxide (CO₂). The sequestration of CO₂ in marine geological formations is one of these systems proposed at the international level to effectively reduce the concentration of atmospheric CO₂. Although permanent containment is expected, it is necessary to determine the risk of leakage to the marine environment. The integrated model for the evaluation of the environmental quality of the marine environment will contribute to determine the potential environmental pathways and effects that are relevant to the consideration of the potential consequences of the leakage of CO₂ and incidental associated substances from the geological formations to the marine environment. In addition, this model will satisfy the requirements for a safe CO₂ storage in sub-seabed geological formations set in the international conventions on the protection of the marine environment (1992 OSPAR Convention and 1996 London Protocol). The objective of this paper is to show how to adapt classical methodologies based on a weight-of-evidence approach to establish the impact of CO₂ leaks in the sediment quality. It is described how the classical methods should modify their application when acidification occurs related to CO₂ leaks being the main potential impact in these areas.