Browsing by Author "Ferreira, Adelaide"
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- Acid mine drainage from the Panasqueira mine and its influence on Zêzere river (Central Portugal)Publication . Candeias, Carla; Ávila, Paula Freire; Silva, Eduardo Ferreira da; Ferreira, Adelaide; Salgueiro, Ana Rita; Teixeira, João PauloThe Panasqueira hydrothermal mineralization, located in central Portugal, is the biggest Sn–W deposit of the Western Europe. The main evidences of the mining exploitation and ore treatment operations are testified with huge tailings, mainly, in the Rio and Barroca Grande areas. The mining and beneficiation processes, at the site, produces metal rich mine wastes. Oxidation of sulfides tailings and flow from open impoundments are responsible for the mobilization and migration of metals from the mine wastes into the environment. Acid mine drainage (AMD) discharged from Rio tailing has a pH around 3 and high metal concentrations. In Zêzere river, Fe and As are the most rapidly depleted downstream from AMD once As adsorbs, coprecipitate and form compounds with iron oxyhydroxides. The Zêzere river waters are oversaturated with respect to kaolinite and goethite and ferrihydrite can precipitate on stream with a near-neutral pH. At sites having low pH the dissolved Fe species in the water, mainly, occur as sulfate complexes due to a high SO4 concentration. Melanterite (Fe2+(SO4)·7(H2O)) and minor amounts of rozenite (Fe2+(SO4)·4(H2O)) and szomolnokite (Fe2+(SO4)·(H2O)) were observed on Rio tailing basement.
- Arsenic removal using synthetic adsorbents : kinetics, equilibrium and column study [Abstract]Publication . Silva, Aurora; Freitas, Olga; Figueiredo, Sónia; Vandervliet, Bie; Ferreira, Adelaide; Fiúza, António
- Availability of trace elements in the abandoned Freixeda gold mine area, NE PortugalPublication . Costa, Maria do Rosário; Ávila, Paula Freire; Ferreira, Adelaide; Silva, Eduardo Ferreira da
- Avaliação do impacte da drenagem de água ácida na hidrogeoquímica do rio Zêzere : o caso de estudo da mina da Panasqueira, PortugalPublication . Ávila, Paula Freire; Ferreira, Adelaide; Salgueiro, Ana Rita; Candeias, Carla; Melo, Rita; Silva, Eduardo Ferreira daA mineralização hidrotermal da Panasqueira localiza-se no centro de Portugal e é o maior depósito de Sn-W da Europa Ocidental. A exploração mineira e as operações do tratamento do minério deram origem a escombreiras de grandes dimensões, principalmente, nas áreas do Cabeço do Pião (escombreira do Rio) e Barroca Grande. A exploração e beneficiação dos processos de tratamento no local geraram rejeitados ricos em metais. A oxidação dos sulfuretos existentes na escombreira e o escoamento pela barragem de contenção de lixiviados, são os responsáveis pela mobilização e migração dos metais a partir dos rejeitados da mina até ao meio ambiente. As descargas das drenagens de água ácida da escombreira do Rio possuem um valor baixo de pH (pH < 3) e elevadas concentrações em metais pesados. No Rio Zêzere, o Fe e o As são os elementos que apresentam o mais rápido decaimento de teores uma vez que o As é adsorvido/e ou coprecipita e forma compostos pouco solúveis com os óxidos e hidróxidos de ferro. Em locais com baixo pH as espécies de Fe dissolvidas ocorrem, principalmente, como sulfatos complexos devido à elevada concentração de SO4 2-. Melanterite (Fe2+(SO4).7(H2O)) e pequenas quantidades de rozenite (Fe2+(SO4).4(H2O)) e szomolnokite (Fe2+(SO4).(H2O)) foram observadas na base da escombreira do Rio.
- Caracterização hidrogeoquímica e radiológica das águas subterrâneas da região de Ervedosa (Vinhais - Norte de Portugal)Publication . Costa, Maria do Rosário; Pereira, Alcides J. S. C.; Novais, Hugo; Ferreira, Adelaide
- In vitro toxicity of arsenic rich waters from an abandoned gold mine in northeast PortugalPublication . Costa, Maria; Gošar, Doroteja; Pinti, Marika; Ferreira, Adelaide; Marušič, Martina BergantABSTRACT: This is a follow-up study of physicochemical water monitoring data from the abandoned Freixeda gold mine in Portugal, where arsenic (As) has remained above drinking water and irrigation limits over the years. The main objective of the current work was to investigate the toxicological potential of As-containing water on human cell line as an indicator of a potential health risk to humans. Six water samples collected in February 2018 were analysed for arsenic, major anions, cations and trace elements. Toxicity experiments were carried out on the human gastrointestinal cell line Caco-2 with five water samples containing As above 10 μg L−1. The results show that groundwater contains higher amounts of dissolved minerals than surface water, particularly with higher concentrations of SO42−, Fe and HCO3− and also higher As(III), reaching 336 μg L−1 (As(T) = 607 μg L−1). In surface waters As concentration decreased and reached 150 μg L−1, mainly as As(V). Metabolic activity was generally lower in Caco-2 cells exposed to As-containing water samples compared to pure As(III) solution, adapted to As concentrations, while production of reactive oxygen species (ROS) was higher. Short-term exposure to As-contaminated water samples also resulted in increased genotoxicity. This study suggests that mixture of As with various chemical elements in water may have a synergistic effect in promoting cytotoxicity. It is likely that prolonged exposure, as is common in areas with contaminated water, would have even more harmful effects.
- In-situ removal of arsenic from groundwater using permeable reactive barriers with iron based sorbentsPublication . Fiúza, António; Silva, Aurora Futuro; Silva, Maria Aurora Soares; Ferreira, Adelaide; Guimarães, Fernanda
- Operating conditions for the treatment of groundwater contaminated by arsenic using iron oxides/hydroxidesPublication . Silva, A.; Freitas, Olga; Figueiredo, S.; Azevedo, Irene; Ferreira, Adelaide; Fiúza, António
- Treatment of groundwater contaminated by arsenic using iron oxides/hydroxidesPublication . Azevedo, Irene; Silva, Maria Aurora Soares; Freitas, Olga; Figueiredo, Sónia; Ferreira, Adelaide; Fiúza, António