The properties of the nano-minerals and hazardous elements: Potential environmental impacts of Brazilian coal waste fire Matheus S. Civeira a , Rafael N. Pinheiro a , Ainara Gredilla b , Silvia Fdez Ortiz de Vallejuelo b , Marcos L.S. Oliveira a , Claudete G. Ramos a , Silvio R. Taffarel a , Rubens M. Kautzmann a , Juan Manuel Madariaga b , Luis F.O. Silva a, ⁎ a Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Victor Barreto, 2288 Centro, 92010-000 Canoas, RS, Brazil b University of the Basque Country (UPV/EHU), Faculty of Science and Technology, Department of Analytical Chemistry, P.O. Box 644, 48080 Bilbao, Spain HIGHLIGHTS • Evaluation of the environmental impact of abandoned Brazilian coal fires area was performed. • Grave effort should be made to set clear restrictions of genered soil utilization in cement industry. • The analytical methodology has been applied to investigate elements occur- rence. GRAPHICAL ABSTRACT abstract article info Article history: Received 15 November 2015 Received in revised form 20 November 2015 Accepted 5 December 2015 Available online xxxx Editor: Thomas Kevin V Brazilian coal area (South Brazil) impacted the environment by means of a large number of coal waste piles emplaced over the old mine sites and the adjacent areas of the Criciúma, Urussanga, and Siderópolis cities. The area studied here was abandoned and after almost 30 years (smokeless visual) some companies use the actual minerals derived from burning coal cleaning rejects (BCCRs) complied in the mentioned area for industry tiles or refractory bricks. Mineralogical and geochemical similarities between the BCCRs and non-anthropogenic geo- logical environments are outlined here. Although no visible flames were observed, this study revealed that auto- combustion existed in the studied area for many years. The presence of amorphous phases, mullite, hematite and other Fe-minerals formed by high temperature was found. There is also pyrite, Fe-sulphates (eg. jarosite) and un- burnt coal present, which are useful for comparison purposes. Bad disposal of coal-dump wastes represents sig- nificant environmental concerns due to their potential influence on atmosphere, river sediments, soils and as well as on the surface and groundwater in the surroundings of these areas. The present study using advanced an- alytical techniques were performed to provide an improved understanding of the complex processes related with sulphide-rich coal waste oxidation, spontaneous combustion and mineral formation. It is reporting huge num- bers of rare minerals with alunite, montmorillonite, szomolnokite, halotrichite, coquimbite and copiapite at the BCCRs. The data showed the presence of abundant amorphous Si–Al–Fe–Ti as (oxy-)hydroxides and Fe-hydro/ oxides with goethite and hematite with various degrees of crystallinity, containing hazardous elements, such Keywords: Coal fires Nano-minerals Human exposure Burning coal cleaning rejects (BCCRs) Science of the Total Environment 544 (2016) 892–900 ⁎ Corresponding author. E-mail address: felipeqma@hotmail.com (L.F.O. Silva). http://dx.doi.org/10.1016/j.scitotenv.2015.12.026 0048-9697/© 2015 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv