Mineralogical and geochemical characterization of gold mining tailings and their potential to generate acid mine drainage (Minas Gerais, Brazil)

For more than 30 years, sulfide gold ores were treated in metallurgic plants located in Nova Lima, Minas Gerais, Brazil, and accumulated in the Cocoruto tailings dam. Both flotation and leaching tailings from a deactivated circuit, as well as roasted and leaching tailings from an ongoing plant, were studied for their acid mine drainage potential and elements’ mobility. Detailed characterization of both tailings types indicates the presence of fine-grain size material hosting substantial amounts of sulfides that exhibit distinct geochemical and mineralogical characteristics. The samples from the ongoing plant show high grades of Fe in the form of oxides, cyanide, and sulfates. Differently, samples from the old circuit shave higher average concentrations of Al (0.88%), Ca (2.4%), Mg (0.96%), and Mn (0.17%), present as silicates and carbonates. These samples also show relics of preserved sulfides, such as pyrite and pyrrhotite. Concentrations of Zn, Cu, Au, and As are higher in the tailings of the ongoing circuit, while Cr and Hg stand out in the tailings of the deactivated circuit. Although the obtained results show that the sulfide wastes do not tend to generate acid mine drainage, leaching tests indicate the possibility of mobilization of toxic elements, namely As and Mn in the old circuit, and Sb, As, Fe, Ni, and Se in the tailings of the plant that still works. This work highlights the need for proper management and control of tailing dams even in alkaline drainage environments such as the one of the Cocoruto dam. Furthermore, strong knowledge of the tailings’ dynamics in terms of geochemistry and mineralogy would be pivotal to support long-term decisions on wastes management and disposal.This work was funded by FCT—Fundação para a Ciência e a Tecnologia through projects UIDB/04683/2020 e UIDP/04683/2020 and Nano-MINENV 029259 (PTDC/CTA-AMB/29259/2017, and by AngloGold Ashanti Brazil

Characterization of Arsenical Mud from Effluent Treatment of Au Concentration Plants, Minas Gerais – Brazil.

The determination of the general properties of arsenical mud was carried out in effluent treatment plant of an Au metallurgical facility, located in Nova Lima, Minas Gerais, Brazil. This effluent, which comes from the calcination stage, is treated via Fe-coprecipitation / lime-neutralization and thus mud with high As concentration is generated. Instrumental methods were applied to investigate physical-chemical characteristics, such as pH, in addition to the forms of occurrence of As and its associations. The results indicated that the mud has an alkaline pH (≈ 8.5), particles with grain size below 20 µm, and As, Fe, S and Al concentrations above 5%. The element As is essentially associated with Fe, Ca, S, and Al, forming phases with wide compositional variation as major and minor constituents generically classified as “complex sulfates” and “compounds with S”. The obtained results could assist optimization of the treatment routes in the plant and even to consider the potential reuse of this arsenic mud as a potential valuable produc

Geoenvironmental characterization of gold mine tailings from Minas Gerais and Goiás, Brazil

For more than two centuries, sulfide gold ores have been treated at metallurgical plants located in Nova Lima, Santa Barbara and Crixás. Brazil. In this study, geochemical, mineralogical, and textural properties of tailings from eight tailings deposits were analysed. The samples show high concentration of Au, hosted in different minerals. In addition, samples contain S, Fe, and As. Sulfides, oxides, and sulfates are present, some as preserved relics. This work highlights different geochemistry and mineralogy, dependent on the nature of the tailings. Such information is critical to support long-term decisions about tailings management and circular economy.This work was supported by FCT through projects UIDB/04683/2020 and UIDP/04683/2020, and the Nano-MINENV project 029259 (PTDC/CTA-AMB/29259/2017), and by AngloGold Ashanti Brasil. Our colleagues at ICT, Centro de Microscopy at Universidade Federal de Minas Gerais (CM-UFMG) and AngloGold Ashanti provide insights and knowledge that greatly aid the research

Adding value to mine waste through recovery Au, Sb, and As: the case of auriferous tailings in the Iron Quadrangle, Brazil

From the colonial era to modern times, gold mining has played a crucial role in shaping Brazil’s economy, culture, and landscape, particularly in the Iron Quadrangle region. Therefore, resulting waste has accumulated in tailings structures, either from deactivated circuits or plants still in production. The present study reveals the potential assessed based on a set of metallurgical tests, assuming specific scenarios depending on the occurrence modes of interesting economic elements. For Au, calcination, leaching, and flotation are promising techniques to recover this element. Tests indicated that toxic elements such as Sb and As could be effectively reused in the form of glass. The generation of other products from dry cleaning techniques was not effective but promising since there was an enrichment of elements with Au, Fe, Al, and K in specific fractions.This research was funded by Fundação para a Ciência and Tecnologia (FCT) through projects UIDB/04683/2020, UIDP/04683/2020, and Nano-MINENV 029259 (PTDC/CTA-AMB/29259/2017)

Portuguese validation of the children's eating attitudes test

CONTEXTO: O Teste de Atitudes Alimentares é o instrumento mais utilizado para avaliar distúrbios alimentares em adultos e adolescentes em uma variedade de culturas e amostras. OBJETIVO: O objetivo deste estudo foi avaliar as propriedades psicométricas da versão portuguesa da Escala de Atitudes Alimentares para Crianças (ChEAT). MÉ;TODO: Novecentos e cinquenta e seis alunos do ensino secundário (565 moças e 391 moços) responderam ao ChEAT. O cálculo da fidelidade teste-reteste foi feito por meio das respostas de 206 participantes da amostra total que voltaram a responder ao questionário após quatro a seis semanas. As análises psicométricas foram realizadas para o total da amostra e para ambos os sexos separadamente. RESULTADOS: A consistência interna e a fidelidade teste-reteste foram satisfatórias. A análise fatorial em componentes na amostra total resultou em quatro fatores que explicam 42,35% da variância total. A composição dos fatores foi semelhante na amostra total e em ambos os sexos. Os fatores denominaram-se: F1 "Medo de Engordar"; F2 "Comportamentos Restritivos e Purgativos"; F3 "Preocupação com a Comida" e F4 "Pressão Social para Comer". A validade concorrente foi explorada com a Escala de Silhuetas Corporais (CDFRS) e foi elevada. CONCLUSÃO: A versão portuguesa do ChEAT é um instrumento útil e válido para a avaliação de atitudes e comportamentos alimentares em adolescentes portugueses.BACKGROUND: The Eating Attitudes Test (EAT) is the most widely used instrument for evaluating eating disorders in adults and adolescents in a variety of cultures and samples. OBJECTIVE: The aim of this study was to analyse the psychometric properties of the Portuguese version of the Children's Eating Attitudes Test (ChEAT). METHOD: Nine hundred and fifty-six Portuguese secondary students (565 girls and 391 boys) answered the ChEAT. The test-retest reliability was obtained with data from 206 participants from the total sample who re-answered the questionnaire after 4-6 weeks. Psychometric analyses were carried out for the total sample and separately for girls and boys. RESULTS: Internal consistency and test-retest reliability were satisfactory. Principal components factorial analysis yielded four factors in the total sample, accounting for 42.35% of the total variance. Factor structure was similar in the total sample and in both genders. Factors were labelled: F1 "Fear of Getting Fat", F2 "Restrictive and Purgative Behaviours", F3 "Food Preoccupation" and F4 "Social Pressure to Eat". The concurrent validity, explored using the Contour Drawing Figure Rating Scale (CDRS) was high. DISCUSSION: The Portuguese version of the ChEAT is a valid and useful instrument for the evaluation of abnormal eating attitudes and behaviours among Portuguese adolescents

Hydrochemistry, elements distribution and their potential recoveries in gold metallurgical treatment tailings dams

Wastewaters are valuable sources of metals and metalloids and can serve as essential resources for their recovery. Characterizing and understanding the occurrence of metals and other compounds, along with identifying the most effective recovery methods, are key steps in unlocking the potential for reusing these resources. The present study focused on analyzing waters from various mining dams in the Iron Quadrangle (IQ) region of Brazil, which contained metals such as Au, Cu, Ni, Zn, and sulfates resulting from the metallurgical treatment of Au. The results revealed a range of metal concentrations in the neutral zone in three tailings. Additionally, a 3D map was created, and a statistical analysis and an exploration of the processes governing mobility and partitioning were conducted to assess the potential for reuse. Notably, the study identified a high potential for Au recovery, particularly through the utilization of sustainable and cost-effective methods such as nanofibers with biosorbents. Overall, this research contributes to the understanding and exploration of potential reuse procedures for strategic metals in various industrial applications.This research was funded by Fundação para a Ciência and Tecnologia (FCT) through projects UIDB/04683/2020, UIDP/04683/2020, and Nano-MINENV 029259 (PTDC/CTA-AMB/ 29259/2017)

SARS-CoV-2 introductions and early dynamics of the epidemic in Portugal

Genomic surveillance of SARS-CoV-2 in Portugal was rapidly implemented by the National Institute of Health in the early stages of the COVID-19 epidemic, in collaboration with more than 50 laboratories distributed nationwide. Methods By applying recent phylodynamic models that allow integration of individual-based travel history, we reconstructed and characterized the spatio-temporal dynamics of SARSCoV-2 introductions and early dissemination in Portugal. Results We detected at least 277 independent SARS-CoV-2 introductions, mostly from European countries (namely the United Kingdom, Spain, France, Italy, and Switzerland), which were consistent with the countries with the highest connectivity with Portugal. Although most introductions were estimated to have occurred during early March 2020, it is likely that SARS-CoV-2 was silently circulating in Portugal throughout February, before the first cases were confirmed. Conclusions Here we conclude that the earlier implementation of measures could have minimized the number of introductions and subsequent virus expansion in Portugal. This study lays the foundation for genomic epidemiology of SARS-CoV-2 in Portugal, and highlights the need for systematic and geographically-representative genomic surveillance.We gratefully acknowledge to Sara Hill and Nuno Faria (University of Oxford) and Joshua Quick and Nick Loman (University of Birmingham) for kindly providing us with the initial sets of Artic Network primers for NGS; Rafael Mamede (MRamirez team, IMM, Lisbon) for developing and sharing a bioinformatics script for sequence curation (https://github.com/rfm-targa/BioinfUtils); Philippe Lemey (KU Leuven) for providing guidance on the implementation of the phylodynamic models; Joshua L. Cherry (National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health) for providing guidance with the subsampling strategies; and all authors, originating and submitting laboratories who have contributed genome data on GISAID (https://www.gisaid.org/) on which part of this research is based. The opinions expressed in this article are those of the authors and do not reflect the view of the National Institutes of Health, the Department of Health and Human Services, or the United States government. This study is co-funded by Fundação para a Ciência e Tecnologia and Agência de Investigação Clínica e Inovação Biomédica (234_596874175) on behalf of the Research 4 COVID-19 call. Some infrastructural resources used in this study come from the GenomePT project (POCI-01-0145-FEDER-022184), supported by COMPETE 2020 - Operational Programme for Competitiveness and Internationalisation (POCI), Lisboa Portugal Regional Operational Programme (Lisboa2020), Algarve Portugal Regional Operational Programme (CRESC Algarve2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF), and by Fundação para a Ciência e a Tecnologia (FCT).info:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost