ASSESSING THE BIOAVAILABILITY OF CONTAMINANTS IN MARINE SEDIMENTS ASSOCIATED WITH CO2 LEAKAGES

Abstract

Carbon capture and storage (CCS) in marine geological formations has been proposed as a mitigation measure for the prevention of global warming. However, leakage of the stored CO2 may occur over time, leading to various effects on ecosystems, especially those related to the mobility of contaminants present in the sediments. This project aims to investigate the potential environmental impacts associated with the acidification of marine sediments subject to leakage of CO2, through the evaluation and modeling of contaminant mobility, bioavailability and toxicity. To this end, a simulator of CO2 leakage is being developed on a laboratory scale for conducting ecotoxicological tests. An innovative methodology for integrating data based on a model that uses "lines of evidence" (LOEs) to monitor the quality of sediment from contaminated areas will be used. This model includes the physicochemical characterization of sediments, the study of the concentration of metals that are mobilized from the sediments to the water column due to the acidification, the toxicity measured in laboratory in both sublethal and lethal levels, and studies of bioaccumulation, taking into account changes in the pH levels. This method allows predicting the effects of CO2 leakage in small or large scale, as well as the immediate and long-term effects and the levels of impact. The results will be applied to regulate the use of this technology in Brazilian jurisdictional waters and optimize test protocols for risk assessment of this new activity, thus providing a tool for decision making that can be used by the proper environmental agencies and companies in the oil and gas sector.