DEFAR - Artigos publicados em periódicos
URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/531
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Item Biological factors influencing As mobilization from an ancient mining region : in vitro studies.(2022) Santos, Alcylane Caldeira; Lopes, L. R.; Teixeira, Mônica CristinaOuro Preto city is located in the Iron Quadrangle, where Arsenic-bearing minerals are easily found; therefore, human exposure to As is a concern. The aim of this study was to assess the influence of organic matter (OM) and microbiota on As mobility. Soil samples were collected from deactivated gold mines to achieve this goal. Soil aliquots (5 g) were exposed to different extractant mixtures: CaCl2, 2.5 mmol −1 (A); CaCl2 + 5 g of proteic biomass - PB (B); CaCl2 + bacterial inoculum (C); CaCl2 + 5 g of PB + inoculum (D); and organic acid solution - OAS (0.1 mol−1) (E). Solubility tests were conducted at room temperature for 120 days (A–D) or 48 h (E). PB increased As mobility up to 600 times compared to that of the control group (A). As mobility in the presence of bacteria was slightly lower thus highlighting the effects of microbiota and OM on As mobilization. Principal component analyses indicated Ca, Fe, Mn, P, Mg, Sr, As, and Cd were the main contributing factors. In the presence of OM, Zn, Cu, Pb, Cd, As, and Cr were leached. The positive effect of OM and indigenous microorganisms on As mobility was confirmed, reinforcing the need to adopt preventive measures to avoid potential environmental damage due to ineffective management of urban and industrial waste deposition in such As-contaminated urban areas.Item Arsenic contamination assessment in Brazil - past, present and future concerns : a historical and critical review.(2020) Teixeira, Mônica Cristina; Santos, Alcylane Caldeira; Fernandes, Carla da Silva; Ng, Jack ChakmengThis paper presents a summary of some relevant documents published during the last decades regarding arsenic contamination in Brazil until December 2018, including scientific papers, reports and regulatory documents. Natural and anthropogenic arsenic sources were covered, excluding those related to agriculture. International “key” documents related to arsenic contamination were used to support the discussion and comparative analysis. This paper aims: (a) to summarize and discuss some available data (including Portuguese written documents) concerning arsenic contamination in Brazil, mainly geographical, geological, geochemical, environmental and health studies; (b) to critically review the published studies comparing their main findings; (c) to describe and compare ancient and recent contamination events; and (d) to highlight key knowledge gaps, and identify promising areas for future researches. The arsenic contamination scenario in Brazil results not only from mining. Natural or anthropogenic emissions caused by great magnitude phenomena as flooding, erosion, landslide and, water scarcity equally impact arsenic mobilization/immobilization equilibria. Our literature review demonstrates that arsenic contamination of soils, sediments and water sources is observed at least at three of the five geographically defined Brazilian regions (Northern, Southern and, Southeastern regions). Arsenic enriched soils, and waters naturally occur all around the country and anthropogenic activities have been the main contributory factor to the environmental contamination since the 18th Century. Geogenic materials (topsoil and mining tailings), and water samples could contain extremely high arsenic concentrations, i.e. 21,000 mg kg−1 or 1,700,000 μg L−1 , respectively, have been found mainly at the “Iron Quadrangle”. Moreover, if we consider both the Brazilian and international parameters, the health risks associated with the human exposition to arsenic are of significant concern. For those reasons, constant monitoring of As contaminated areas in Brazil is mandatory. Furthermore, it is necessary to learn from the mistakes made in the past in order to prevent or minimize future problems.