Natural attenuation processes applying to antimony: A study in the abandoned antimony mine in Goesdorf, Luxembourg Montserrat Filella a,b, ⁎, Simon Philippo c , Nelson Belzile d , Yuwei Chen d , François Quentel e a Institut F.A. Forel, University of Geneva, Route de Suisse 10, CH-1290 Versoix, Switzerland b SCHEMA, Rue Principale 92, L-6990 Rameldange, Luxembourg c Musée National d'Histoire Naturelle, 25 rue Münster, L-2160 Luxembourg d Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 e UMR-CNRS 6521, Université de Bretagne Occidentale, 6 Avenue V. Le Gorgeu, CS 93837, F-29238 Brest Cedex 3, France abstract article info Article history: Received 9 July 2009 Received in revised form 21 August 2009 Accepted 23 August 2009 Available online 22 September 2009 Keywords: Antimony Goesdorf Valentinite Antimony minerals Oxalate buffer extraction The processes leading to the attenuation of the antimony concentration in the water draining from the abandoned antimony mine in Goesdorf, Luxembourg, have been studied. Antimony has been mined in Goesdorf since Roman times from a stibnite-rich mesothermal vein system hosted in metasedimentary schist. The draining waters have pH values between 7 and 8 because the mineralization itself contains calcite and dolomite. This study combines the identification of minerals in the supergene zone with the application of bulk techniques (e.g., measurement of antimony in the waters of the adit and the creek draining the mine, sediment sequential extractions) over a period of five years. Antimony concentrations in the water that leaves the supergene zone are controlled by the dissolution of stibnite and the subsequent formation of Sb(III) oxides and sulphates. The relative proportions of the main secondary minerals can be qualitatively estimated as follows: 70% valentinite, 15% senarmontite and 12% sulphates (coquandite, klebelsbergite and peretaite). Further antimony attenuation along the adit and the creek that drain the mine waters is due partly to dilution, through mixing with waters that have not been in contact with the ore, and partly to sorption onto amorphous iron and manganese oxides present in the colluvial sediments. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Antimony is a naturally occurring element that belongs to group 15 of the periodic table of the elements, along with N, P, As and Bi. General aspects of Sb behaviour in the environment, its solution chemistry and the role of biota have been thoroughly reviewed (Filella et al., 2002a, 2002b, 2007). In addition, a critical overview of the current state of the research of Sb has been published very recently (Filella et al., 2009a). This critical appraisal shows that, although Sb has been the focus of considerable scientific research over the last years, many aspects of its environmental behaviour remain largely misunderstood. In this study, processes related to Sb attenuation have been studied in an abandoned Sb mine. Even if, unfortunately, studies in mine areas too often fail to go beyond the level of description, remaining close to a follow-up pollution survey, and, as such, are of limited scientific interest, small mines are interesting systems to study from an envi- ronmental point of view because contrasting chemical environments— including wide concentration ranges for some elements—are found in a relatively small, well-characterised spatial scale. The mine investigated here is situated in Goesdorf, Luxembourg, where Sb mining has existed since Roman times in a stibnite-rich mesothermal vein system hosted in metasedimentary schist. The mineralization contains calcite and dolomite and draining waters have pH values between 7 and 8. Because of the circumneutral pH of the draining waters, the processes that can be studied in this system are close to those taking place in most surface water systems. Many of the adits in the Goesdorf mine have collapsed, but one adit still provides easy access to waters which have interacted with the vein. This study explores different potential barriers to Sb dispersion, namely the formation of insoluble Sb-containing phases, sorption onto solid surfaces and natural dilution. This mine has already proved useful as a model system for studying inorganic colloid composition and migration (Filella et al., 2009b). 2. Experimental section 2.1. Site description 2.1.1. Site location The mine is situated 1 km east of the village of Goesdorf (490 m asl) in the Eisleck, in the North of the Grand Duchy of Luxembourg. The Science of the Total Environment 407 (2009) 6205–6216 ⁎ Corresponding author. Institut F.A. Forel, University of Geneva, Route de Suisse 10, CH-1290 Versoix, Switzerland. E-mail address: montserrat.filella@unige.ch (M. Filella). 0048-9697/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.scitotenv.2009.08.027 Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv