C´írculo de Cultura freireano

Este trabalho é consequência de uma experiência vivenciada no Curso Técnico em Guia de Turismo Subsequente ao Ensino Médio, ofertado pelo Instituto Federal de Educação, Ciência e Tecnologia da Paraíba, Câmpus Avançado Cabedelo Centro, na Barra do Mamanguape, Rio Tinto-PB. Nosso objetivo é relatar a vivência didático-pedagógica com os educandos durante a execução do curso profissional, em que utilizamos a metodologia freireana, que tem como base a relação dialógica entre o educando e o educador, valendo-nos do círculo de cultura como instrumento de interação entre esses atores e sua realidade. Na trajetória da elaboração e efetivação do método referido, registrou-se a experiência exitosa de Angicos-RN. No trabalho que ora apresentamos, constatamos que o método freireano pode e deve ser utilizado para além do ato de alfabetizar, já que a nossa experiência se deu de maneira também exitosa em turmas de ensino profissional. Por fim, concluímos que o círculo de cultura é um instrumento metodológico atemporal e totalmente viável para preencher as lacunas existentes em um modelo sistêmico de educação que, muitas vezes, não atende à heterogeneidade sociocultural brasileira e suas particularidades.

Rio Tinto enters lithium production in Argentina

Headline ARGENTINA: Rio Tinto enters lithium production

Biogeochemical Niches of Fe-cycling Communities Influencing Heavy Metal Transport Along the Rio Tinto, Spain

In the mining-impacted Rio Tinto, Spain, Fe-cycling microorganisms influence the transport of heavy metals (HMs) into the Atlantic Ocean. However, it remains largely unknown how spatial and temporal hydrogeochemical gradients along the Rio Tinto shape the composition of Fe-cycling microbial communities and how this in turn affects HM mobility. Using a combination of DNA- and RNA-based 16S rRNA (gene) amplicon sequencing and hydrogeochemical analyses, we explored the impact of pH, Fe(III), Fe(II) and Cl - on Fe-cycling microorganisms. We showed that the water column at the acidic (pH 2.2) middle course of the river was colonized by Fe(II) oxidizers affiliating with Acidithiobacillus and Leptospirillum. At the upper estuary, daily fluctuations of pH (2.7-3.7) and Cl - (6.9-16.6 g/L) contributed to the establishment of a unique microbial community, including Fe(II) oxidizers belonging to Acidihalobacter , Marinobacter and Mariprofundus identified at this site. Furthermore, DNA- and RNA-based profiles of the benthic community suggested that acidophilic and neutrophilic Fe(II) oxidizers (e.g., Acidihalobacter , Marinobacter and Mariprofundus ), Fe(III) reducers (e.g., Thermoanaerobaculum ) and sulfate-reducing bacteria drive the Fe cycle in the estuarine sediments. RNA-based relative abundances of Leptospirillum at the middle course as well as abundances of Acidohalobacter and Mariprofundus at the upper estuary were higher, compared to DNA-based results, suggesting potentially higher level of activity of these taxa. Based on our findings, we propose a model of how tidal water affects the composition and activity of the Fe-cycling taxa, playing an important role in the transport of HMs (e.g., As, Cd, Cr and Pb) along the Rio Tinto. Importance The estuary of the Rio Tinto is a unique environment in which extremely acidic, heavy metal- and especially iron-rich river water is mixed with seawater. Due to the mixing events, the estuarine water is characterized by a low pH, almost sea water salinity and high concentrations of bioavailable iron. The unusual hydrogeochemistry maintains unique microbial communities in the estuarine water and in the sediment. These communities include halotolerant iron-oxidizing microorganisms which typically inhabit acidic saline environments and marine iron-oxidizing microorganisms, which, in opposite, are not typically found in acidic environments. Furthermore, highly saline estuarine water favored the prosperity of acidophilic heterotrophs, typically inhabiting brackish and saline environments. The Rio Tinto estuarine sediment harbored a diverse microbial community with both, acidophilic and neutrophilic members that can mediate the iron cycle, and in turn, can directly impact the mobility and transport of heavy metals in the Rio Tinto estuary.

Unveiling microbial preservation under hyperacidic and oxidizing conditions in the Oligocene Rio Tinto deposit

The preservation of biosignatures on Mars is largely associated with extensive deposits of clays formed under mild early Noachian conditions (> 3.9 Ga). They were followed by widespread precipitation of acidic sulfates considered adverse for biomolecule preservation. In this paper, an exhaustive mass spectrometry investigation of ferric subsurface materials in the Rio Tinto gossan deposit (~ 25 Ma) provides evidence of well-preserved molecular biosignatures under oxidative and acidic conditions. Time of flight secondary ion mass spectrometry (ToF–SIMS) analysis shows a direct association between physical-templating biological structures and molecular biosignatures. This relation implies that the quality of molecular preservation is exceptional and provides information on microbial life formerly operating in the shallow regions of the Rio Tinto subsurface. Consequently, low-pH oxidative environments on Mars could also record molecular information about ancient life in the same way as the Noachian clay-rich deposits.

Hydrogeochemical Variability of the Acidic Springs in the Rio Tinto Headwaters

Peña de Hierro, located in southwest Spain, encompasses the springs and headwaters for the Rio Tinto River that emerge above normal faults and has been mined for its rich sulfide ore since 2500 BC. The springs are typically characterized by an orange coloration, typical pH of ~2.33, and contain elevated concentrations of heavy metals that are produced by acid rock drainage (ARD). ARD is a natural phenomenon that results from chemolithoautotrophs metabolizing the sulfide ore. Mining has amplified the magnitude of the acidity and concentrations of heavy metals evidenced within sedimentary cores from the Huelva estuary. Acidity, redox state, hydrochemistry and isotopic analyses were examined for the purpose of characterizing the subsurface flows and determining the interconnectivity of the groundwaters. Previous studies have documented the geochemistry of the springs, dating a select few, yet many springs remain uncharacterized. Acidity presented spatial variability throughout the field area, caused by extensive sulfide interactions which generated and modified the pH. Redox exhibited a large range of values due to oxygen diffusivity though the fracture network. The surrounding geology is highly heterogeneous because of intensive deformation during the Variscan and Tertiary periods, and this heterogeneity is shown in the varied aqueous chemistry. Fractionation patterns observed in δ2H and δ18O values predominantly reflected enrichment by intensive evaporation and depletion in δ18O as a result of the proposed sulfatic-water model for Rio Tinto’s hydrogeology. The analysis illustrates minimal hydrologic interconnectivity, evidenced by the extensive physical and chemical contrasts within such a small proximity.

Participação de um consórcio de alumínio no Brasil: um estudo de caso sobre ações sustentáveis

A Alumar (Consórcio de Alumínio do Maranhão S.A.), instalada em São Luís, é uma empresa formada por um consórcio entre as mineradoras transnacionais Alcoa, Rio Tinto e South32. É uma das maiores produtoras de alumina do mundo, e uma das maiores empresas instaladas no Maranhão. Era também uma grande produtora de alumínio, mas as atividades com o metal foram encerradas em março de 2015. A Alumar sempre esteve presente na vida econômica, social e cultural no estado. Investimentos, parcerias, pesquisas, geração de emprego e renda, qualificação profissional e ações sustentáveis na fabricação da alumina deram à Alumar, ao longo dessas quatro décadas, seu caráter de liderança no segmento. De maneira ativa e participativa, a Alumar conquistou excelência operacional por meio do absoluto respeito pela vida, diversidade, meio ambiente e sustentabilidade, além de intensa participação nas comunidades com foco nas áreas da educação, geração de emprego e renda e engajamento. O presente estudo de caso, tem por objetivo apresentar as principais características da trajetória deste consórcio e a sua importância para o desenvolvimento industrial local.