Browsing by Author "Salgueiro, Ana Rita"
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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.
- Assessment of Panasqueira mine surrounding soils through a contamination factorPublication . Candeias, Carla; Salgueiro, Ana Rita; Silva, Eduardo Ferreira da; Ávila, Paula Freire
- Assessment of potential health risk for inhabitants of S. Francisco de Assis living near Panasqueira mine (Portugal)Publication . Candeias, Carla; Melo, Rita; Ávila, Paula Freire; Ferreira, E.; Salgueiro, Ana Rita; Teixeira, João Paulo
- Assessment of the soil contamination by potentially toxic elements in Aljustrel mining area in order to implement soil reclamation strategiesPublication . Candeias, Carla; Silva, E. Ferreira da; Salgueiro, Ana Rita; Pereira, H. Garcia; Matos, João Xavier; Ávila, Paula Freire
- 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.
- Heavy metal pollution in mine-soil-plant system in S. Francisco de Assis - Panasqueira mine (Portugal)Publication . Candeias, Carla; Melo, Rita; Ávila, Paula Freire; Silva, Eduardo Ferreira da; Salgueiro, Ana Rita; Teixeira, João PauloThe active Panasqueira mine is a tin–tungsten (Sn–W) mineralization hosted by metasediments with quartz veins rich in ferberite. The economic exploitation has been focused on wolframite, cassiterite and chalcopyrite. The mineralization also comprises several sulphides, carbonates and silver sulphosalts. The mining and beneficiation processes produces arsenic-rich mine wastes laid up in huge tailings and open air impoundments that are the main source of pollution in the surrounding area, once the oxidation of sulphides can result in the mobilization and migration of trace metals/metalloids from the mining wastes into the environment, releasing contaminants into the ecosystem. A geochemical survey was undertaken, in order to investigate the environmental contamination impact on agricultural and residential soils in S. Francisco de Assis village due to the mining activities. Rhizosphere samples, vegetables (Solanum tubersum sava and Brassica olerácea L.) which constitute an important part of the local human diet), irrigation waters and road dusts were collected in private residences in S. Francisco de Assis village. According to the Ontario guidelines ( Ministry of Environment, 2011), the Arsenic contents in the rhizosphere soils exceed 20 times the reference value for agricultural soils (11 mg kg-1). The result obtained showed that some edible plants frequently used in the region could be enriched in these metals/metalloids and may represent a serious hazard if consumed. The potatoes tend to have a preferential accumulation in the leaves and roots while in cabbages most elements have a preferential accumulation in the roots. An index of the risk for residents, due to ingesting of these metals/metalloids, by consuming vegetables grown around the sampling area, was calculated and the result indicates that the inhabitants of S. Francisco de Assis village are probably exposed to some potential health risks through the intake of arsenic, cadmium and also lead via consuming their vegetables.
- Heavy metal pollution in Mine-Soil-Plant System in S. Francisco de Assis - Panasqueira mine (Portugal)Publication . Melo, Rita; Candeias, Carla; Ávila, Paula Freire; Salgueiro, Ana Rita; Ferreira, A.; Silva, Eduardo Ferreira da
- Modelling the impact of Panasqueira mine on the ecosystems and human health : a multidisciplinary approachPublication . Candeias, Carla; Silva, Eduardo Ferreira da; Salgueiro, Ana Rita; Ávila, Paula Freire; Coelho, P.; Teixeira, J. P.
- Quantitative-spatial assessment of soil contamination in S. Francisco de Assis due to mining activity of the Panasqueira mine (Portugal)Publication . Silva, Eduardo Ferreira da; Ávila, Paula Freire; Salgueiro, Ana Rita; Candeias, Carla; Pereira, Henrique GarciaThrough the years, mining and beneficiation processes produces large amounts of As-rich mine wastes laid up in huge tailings and open-air impoundments (Barroca Grande and Rio tailings) that are the main source of pollution in the surrounding area once they are exposed to the weathering conditions leading to the formation of AMD and consequently to the contamination of the surrounding environments, in particularly soils. In order to investigate the environmental contamination impact on S. Francisco de Assis (village located between the two major impoundments and tailings) agricultural soils, a geochemical survey was undertaken to assess toxic metals associations, related levels and their spatial distribution, and to identify the possible contamination sources. According to the calculated contamination factor, As and Zn have a very high contamination factor giving rise to 65.4 % of samples with a moderate to high pollution degree; 34.6 % have been classified as nil to very low pollution degree. The contamination factor spatial distribution put in evidence the fact that As, Cd, Cu, Pb, and Zn soils contents, downstream Barroca Grande tailing, are increased when compared with the local Bk soils. The mechanical dispersion, due to erosion, is the main contamination source. The chemical extraction demonstrates that the trace metals distribution and accumulation in S. Francisco de Assis soils is related to sulfides, but also to amorphous or poorly crystalline iron oxide phases. The partitioning study allowed understanding the local chemical elements mobility and precipitation processes, giving rise to the contamination dispersion model of the study area. The wind and hydrological factors are responsible for the chemical elements transport mechanisms, the water being the main transporter medium and soils as one of the possible retention media.
- Soil geochemical survey in Panasqueira mine surroundings (Central Portugal) : mining, metal(loid)s and related environmental impactPublication . Candeias, Carla; Salgueiro, Ana Rita; Silva, Eduardo Ferreira da; Ávila, Paula Freire; Melo, Rita