RT Journal Article
T1 Geochemical processes in a highly acidic pit lake of the Iberian Pyrite Belt (SW Spain)
A1 Ruiz Cánovas, Carlos
A1 Peiffer, Stefan
A1 Macías Suárez, Francisco
A1 Olías Álvarez, Manuel
A1 Nieto Liñán, José Miguel
AB Compared with pit lakes originated by coal mining, little is known about in-lake neutralization processes in pit lakes from sulfide ore mining in hard rock substrates, which are typically very deep and acidic and receive low carbon (C) inputs and groundwater flows. Physicochemical processes in water and sediments from a pit lake (San Telmo, 130 m deep) in the Iberian Pyrite Belt were investigated. San Telmo is a meromictic and highly acidic (pH 2.8) pit lake due to pH buffering by precipitation of Fe(III) minerals (schwertmannite and jarosite). The sediments have a low abundance of C (below 0.60%) and iron minerals (below 0.12%) compared to most coal-mining pit lakes. In San Telmo sediments, iron reduction and sulfide oxidation may be thermodynamically favoured due to low pH values in pore waters (below 3.8) and the presence of reactive iron. Although schwertmannite is the main ferric mineral precipitating in the water column, mineralogical analyses reveal a low abundance of schwertmannite in the sediment. This may be due to the preferential use of this mineral in reduction reactions mediated by bacteria, together with a low replenishment rate of the schwertmannite pool in the sediment. The transformation of reactive iron (schwertmannite and jarosite) into goethite may limit sulfate reduction, promoting acidic conditions in the sediment. As long as the acid mine drainage continues to discharge into the lake, the pH buffering exerted by ferric minerals in the sediments will limit the neutralization of the pH by sulfate reduction.
PB Elsevier
SN 0009-2541
YR 2015
FD 2015
LK https://hdl.handle.net/10272/23055
UL https://hdl.handle.net/10272/23055
LA eng
NO Ruiz-Cánovas, C., Peiffer, S., Macías, F., Olías, M., & Nieto, J. M. (2015). Geochemical processes in a highly acidic pit lake of the Iberian Pyrite Belt (SW Spain). In Chemical Geology (Vol. 395, pp. 144–153). Elsevier BV. https://doi.org/10.1016/j.chemgeo.2014.12.007
NO This work has been financed through the projects CGL2013-48460-C2-1-R (Spanish Ministry of Economy and Competitiveness) and P11-RNM-7199 (Andalusian Regional Government). The Deutscher Akademischer Austausch Dienst (DAAD) provided financial support for the stay of CRC at the University of Bayreuth. The authors gratefully acknowledge the field assistance of Dr. Juan Antonio Morales and Dr. Joaquin Delgado, and the technical support of Dr. Marcus Bauer, Dr. Klaus H. Knorr, Martin Back, Martina Rohr, Isolde Baumann, Jutta Eckert and Karin Söllner (among others). The comments and suggestions of the editor Carla M. Koretsky and two anonymous reviewers significantly improved the original manuscript.
DS Repositorio Institucional de la Universidad de Huelva
RD 1 jun 2026