Trace element mobility during the injection of water-dissolved CO2 into basalts

[Geoengineering News]

https://www.nature.com/articles/s41598-026-57307-6

Authors: Abdirizak Omar, Mouadh Addassi, Niccolo Menegoni, Serguey Arkadakskiy, Jakub Fedorik, Zeyad Ahmed, Noushad Kunnummal, Thomas Finkbeiner, Sigurdur R. Gislason, Abdulkader Afifi, Hussein Hoteit & Eric H. Oelkers 

10 June 2026

Abstract

In-situ carbon mineralization in basalts has been identified as a permanent and scalable method to sequester CO2 in the subsurface. The extent of potentially toxic trace element mobilization during basalt dissolution, however, remains poorly constrained. The Jizan carbon sequestration pilot was undertaken to assess the potential for carbon disposal through the mineralization of water-dissolved CO2 injected into subsurface basalts in arid regions. The temporal evolution of trace element and potentially toxic metal concentrations in the Jizan groundwater during and following the injection of CO2-charged water and its recirculation has been assessed. Twenty-eight representative production well fluid samples were selected and analyzed by ICP-MS. Element mobility was quantified by comparing the increase in concentration of the selected elements in the aqueous phase to the corresponding increase in sodium concentration. Results indicate that the mobility of trace elements in the Jizan system is limited, with the average mobility of most trace elements remaining below 20% of that of sodium. Furthermore, the maximum measured concentrations of most trace elements are significantly below the acceptable levels in drinking water before, during, and after the CO2 injection. These observations suggest the risk of groundwater pollution during in-situ carbon mineralization efforts in basalt is likely minimal.

Source: Scientific Reports