Comparative study of iron and trace element mobilization during Fe-Oxide bioreduction in mine tailings: a case study of Ensenada Chapaco (Chile) and Portman Bay (Spain)
Benaiges-Fernandez, Robert (Universitat de Barcelona)
Palau, Jordi (Universitat de Barcelona)
Urmeneta, Jordi (Universitat de Barcelona)
Soler, Josep M. (Institut de Diagnosi Ambiental i Estudis de l'Aigua)
Cama, Jordi (Institut de Diagnosi Ambiental i Estudis de l'Aigua)
Dold, Bernhard (Pontificia Universidad Católica del Perú)

Fecha:	2025
Resumen:	Bioreduction of Fe-oxides in mine tailings deposited under marine conditions releases Fe and associated trace elements (e. g. , Ti, Ni, Cd, Pb), leading to contamination of the marine environment. Sea-tailings disposal (STD) along the northern coast of Chile (Ensenada Chapaco) and along the eastern coast of Spain (Portman Bay) results in an adverse impact on the environment. This paper focuses on bioreduction under marine conditions. To this end, two column experiments were carried out with samples from Portman Bay and Ensenada Chapaco. Lactate (i. e. , organic matter source) was supplied during the experiments. The results obtained are compared with those from batch experiments performed under similar conditions. In the column filled with Portman Bay tailings, the high content of magnetite (15 wt%) in contact with water gives rise to a large magnetite surface area and abundant Fe(III), which results in a high release of Fe(II) and trace metals (TE). Since Fe(II) adsorbs onto the magnetite surface reducing the availability of Fe(III), the magnetite bioreduction and the consequent TE release decrease after 2000 h. By contrast, the magnetite bioreduction lasts longer (3000 h) in the column with Ensenada Chapaco tailings. This is because a lower magnetite content in the tailings (1 wt%) provides a smaller reactive surface area yielding less Fe(III). Consequently, the concentrations of Fe(II) and TE in the output solutions are lower, which slows down the Fe(II) adsorption onto magnetite. This results in a a longer magnetite bioreduction. Bioreduction is regulated by the availability of Fe(III) in both columns. It is inferred that the bioreduction rate diminishes as a function of time and increases as a function of soluble Fe(II) concentration. Moreover, the concentrations of TE released from the two bioreduced tailings exceed the elemental concentrations under marine conditions.
Resumen:	Bioreduction of Fe-oxides in mine tailings deposited under marine conditionsreleases Fe and associated trace elements (e. g. , Ti, Ni, Cd, Pb), leading tocontamination of the marine environment. Sea-tailings disposal (STD) along thenorthern coast of Chile (Ensenada Chapaco) and along the eastern coast of Spain(Portman Bay) results in an adverse impact on the environment. This paper focuseson bioreduction under marine conditions. To this end, two column experiments werecarried out with samples from Portman Bay and Ensenada Chapaco. Lactate (i. e. ,organic matter source) was supplied during the experiments. The results obtainedare compared with those from batch experiments performed under similarconditions. In the column filled with Portman Bay tailings, the high content of magnetite(15 wt%) in contact with water gives rise to a large magnetite surface area andabundant Fe(III), which results in a high release of Fe(II) and trace metals (TE). SinceFe(II) adsorbs onto the magnetite surface reducing the availability of Fe(III), themagnetite bioreduction and the consequent TE release decrease after 2000 h. Bycontrast, the magnetite bioreduction lasts longer (3000 h) in the column withEnsenada Chapaco tailings. This is because a lower magnetite content in the tailings(1 wt%) provides a smaller reactive surface area yielding less Fe(III). Consequently,the concentrations of Fe(II) and TE in the output solutions are lower, which slowsdown the Fe(II) adsorption onto magnetite. This results in a a longer magnetitebioreduction. Bioreduction is regulated by the availability of Fe(III) in both columns. It is inferred that the bioreduction rate diminishes as a function of time andincreases as a function of soluble Fe(II) concentration. Moreover, the concentrationsof TE released from the two bioreduced tailings exceed the elemental concentrationsunder marine conditions.
Ayudas:	Agencia Estatal de Investigación CGL2017-82331-R Ministerio de Ciencia e Innovación PID2020-119196RB-C22 Ministerio de Ciencia e Innovación CEX2018-000794-S Generalitat de Catalunya 2021 SGR 00308
Nota:	Altres ajuts: Fondo de Investigación Pesquera y de Acuicultura; FIPA de SUBPESCA (proyecto FIP 2015-11) de Xile
Derechos:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	Oxide reduction ; Sea tailings deposition ; Marine pollution ; Mine waste ; Magnetite
Publicado en:	Geologica acta, Vol. 23 (2025) , p. 1-12 (Tribute to Esteve Cardellach) , ISSN 1696-5728

Adreça original: https://revistes.ub.edu/index.php/GEOACTA/article/view/45976
Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/435869
DOI: 1696-5728
DOI: 10.1344/GeologicaActa2025.23.5

12 p, 3.1 MB

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