title: Effects on the mobility of metals from acidification caused by possible CO₂ leakage from sub-seabed geological formations.
abstract: Carbon dioxide capture and storage (CCS) in submarine geological formations has been proposed as a mitigation measure for the prevention of global warming. However, leakage of CO2 to overlying sediments may occur over time, leading to various effects on ecosystems. Laboratory-scale experiments were performed, involving direct release of carbon dioxide into sediment, inside non-pressurized chambers, in order to provide data on the possible effects of CO2 leakage from geological storage sites on the fate of several metals. Marine sediments from three sites with different levels of contamination were sampled and submitted to acidification by means of CO2 injection. The experiment lasted 10 days and sediment samples were collected at the beginning and end of the experiment and pore water was extracted for metal analysis. The results revealed that mobility of metals from sediment to pore water depends on the site, metal and length of time exposed. Mobilization of the metals Al, Fe, Zn, Co, Pb and Cu increases with acidification, and this response generally increases with time of exposure to CO2 injection. The geochemical model applied suggests that acidification also influences the speciation of metals, transforming metals and metalloids, like As, into species much more toxic to biota. The data obtained from this study will be useful for calculating the potential risk of CCS activities to the marine environment.
authors.affiliation: Cátedra UNESCO/UNITWIN/WiCop, Departamento de Química Física, Universidad de Cádiz, CP 11510 Puerto Real, Cádiz, Spain.
authors.forename: Manoela Romanó
authors.initials: MR
authors.lastname: de Orte
authors.affiliation: Departamento de Geodinámica y Paleontología, Universidad de Huelva, Campus 'El Carmen', CP 21071, Huelva, Spain. Electronic address: aguasanta.miguel@dgeo.uhu.es.
authors.forename: Aguasanta M
authors.initials: AM
authors.lastname: Sarmiento
authors.affiliation: Cátedra UNESCO/UNITWIN/WiCop, Departamento de Química Física, Universidad de Cádiz, CP 11510 Puerto Real, Cádiz, Spain.
authors.forename: Maria Dolores
authors.initials: MD
authors.lastname: Basallote
authors.affiliation: Cátedra UNESCO/UNITWIN/WiCop, Departamento de Química Física, Universidad de Cádiz, CP 11510 Puerto Real, Cádiz, Spain.
authors.forename: Araceli
authors.initials: A
authors.lastname: Rodríguez-Romero
authors.affiliation: Cátedra UNESCO/UNITWIN/WiCop, Departamento de Química Física, Universidad de Cádiz, CP 11510 Puerto Real, Cádiz, Spain.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Riba
authors.affiliation: Cátedra UNESCO/UNITWIN/WiCop, Departamento de Química Física, Universidad de Cádiz, CP 11510 Puerto Real, Cádiz, Spain.
authors.forename: Angel
authors.initials: A
authors.lastname: Delvalls
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry*; D055593:Geological Phenomena; D057232:Global Warming; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000032:analysis*; D012623:Seawater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008670:Metals; D014874:Water Pollutants, Chemical; D002245:Carbon Dioxide
keywords: Acidification; Carbon capture and storage (CCS); Geochemical modelling; Metal mobility; Pore water; Sediment