Erica andevalensis and Erica australis growing in the same extreme environments: Phytostabilization potential of mining areas Rafael Pérez-López a, ⁎, Belén Márquez-García b,1 , Maria Manuela Abreu c , José Miguel Nieto a , Francisco Córdoba b a Department of Geology, University of Huelva, Campus “El Carmen,” 21071, Huelva, Spain b Department of Environmental Biology and Public Health, University of Huelva, Campus “El Carmen,” 21071, Huelva, Spain c Instituto Superior de Agronomia, Universidade de Lisboa, Unidade de Investigação de Química Ambiental (UIQA), Tapada da Ajuda, 1349-017 Lisboa, Portugal abstract article info Article history: Received 20 August 2013 Received in revised form 27 January 2014 Accepted 6 April 2014 Available online xxxx Keywords: São Domingos mine Hazardous elements Spontaneous heather Metals Tolerance Phytoremediation Mining activities in the abandoned São Domingos mine (Portugal, Iberian Pyrite Belt, IPB) generated a large amount of sulphide-rich waste rocks and tailings. Erica andevalensis Cabezudo and Rivera and Erica australis L. plants grow spontaneously in contaminated sites that have high concentrations of potentially hazardous elements, high acidity and nutrient deficiency. The aim of this paper was to analyse the behaviour of monospecific and mixed communities of both Erica species in these extreme environments in order to evaluate their potential for phytostabilization of soils and mining wastes. Metal and metalloids were analysed in the soils (total and available fraction) and in the roots and above-ground biomass of the plants, and these values were then used to estimate uptake, tolerance, translocation and accumulation in the plants. The plants showed a high content of trace elements in the roots and above-ground biomass. In fact, the content of chemical elements in the aerial parts was higher than the range considered as normal for Al and Fe, and exceeded the toxic values for As, Mn and Pb. These values were superior to those found in the available soil fraction for these elements, and even superior to the soil total content for Mn. The lack of phytotoxicity symptoms suggests that Erica plants can be considered as a Mn-accumulator and acid-, Al-, As-, Fe- and Mn-tolerant. Furthermore, both E. andevalensis and E. australis were found to form a large biomass in monospecific and mixed communities on both wet acid sulphate soils/sediments in riverbanks and dry mine tailings and contaminated soils. Hence, both Erica species can be considered suitable for phytostabilization of metal(loid)-polluted sites in abandoned mining districts of the IPB. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Trace element contamination of soils affected by acid mine drainage (AMD) from the mining of sulphide-bearing ore deposits is a main cause of environmental contamination throughout the world. Trace elements are not subject to chemical or biochemical decomposition and remain active for a long time in the environment. This is a serious problem due to the high ability of contaminants to accumulate in the biota and cause significant toxicity in microorganisms, plants, animals and humans. The tolerance of some plant species to the accumulation of hazardous chemical elements is proposed as an in situ low-cost technology for remediation of contaminated soils, and has received con- siderable attention in recent years (Ma et al., 2011; Moreno-Jiménez et al., 2011; Sun et al., 2011). In particular, phytostabilization is a phytoremediation strategy that consists of immobilising metals in soil or roots, thus reducing their mobility and bioavailability in the environ- ment (Abreu and Magalhães, 2009; Pivetz, 2001). The Iberian Pyrite Belt (IPB; SW Iberian Peninsula, Spain and Portugal) has been acknowledged as a world-class massive sulphide province. The IPB holds over one hundred deposits and 1700 Tg of reserves (Sáez et al., 1999). Mining activity dates back to 5000 years ago and has generated a large volume of AMD by oxidation of sulphide-rich mining wastes, which is drained by the Tinto and Odiel river basins in the Spanish sector and the Guadiana river basin between the Spanish and Portuguese sectors. The production of AMD has strongly impacted on the quality of these watercourses (Abreu et al., 2010; Delgado et al., 2009; Nieto et al., 2007) as well as on the sediments and soils of the region (Abreu and Magalhães, 2009; Fernández-Caliani et al., 2009). In the IPB, two heather species of the genera Erica (Ericaceae family) have been described as tolerant to metals: Erica australis L. and Erica andevalensis Cabezudo and Rivera (Abreu et al., 2008; Monaci et al., 2011). Erica andevalensis is an endemic heather that grows only in min- ing areas of the IPB (Cabezudo and Rivera, 1980). Both Erica species can survive in hostile soils with high concentrations of hazardous elements, Geoderma 230–231 (2014) 194–203 ⁎ Corresponding author. Tel.: +34 95 921 9819; fax: +34 95 921 9810. E-mail addresses: rafael.perez@dgeo.uhu.es (R. Pérez-López), manuelaabreu@isa.utl.pt (M.M. Abreu). 1 Present address: Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Gent, Belgium. http://dx.doi.org/10.1016/j.geoderma.2014.04.004 0016-7061/© 2014 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Geoderma journal homepage: www.elsevier.com/locate/geoderma