Browsing by Author "Santos, E.S."
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- Capacidade de absorção do chumbo por plantas do género Cistus espontâneas em ambientes mineirosPublication . Abreu, Maria Manuela; Santos, E.S.; Anjos, C.; Magalhães, M.C.F.; Nabais, C.Mining activity can give rise to large quantities of chemically unstable waste rocks and tailings which can drain potential environmentally harmful lixiviates rich in chemical elements. Plants growing in such environments can minimize chemical, physical and visual negative impacts. To evaluate lead absorption by native Cistus growing in Braçal (NW Portugal) and São Domingos (SE Portugal) mining areas, Cistus inflatus (aerial parts) and Cistus ladanifer (leaves) were analysed by instrumental neutron activation analysis and atomic absorption spectrometric, respectively, after acid digestions. Soils were characterized by pH(H2O), organic carbon, cation exchange capacity, free Fe and Mn, total nitrogen, and assimilable K and P. Total lead was determined in soils (fraction < 2 mm) by inductively coupled plasma emission spectrometry after acid digestion, and Pb available fraction was determined by atomic absorption spectrometric and inductively coupled plasma mass spectroscopy after calcium nitrate extraction. High concentrations of total Pb are present in both mining areas soils. However, in São Domingos soils the Pb available fraction is smaller (8.3–67.3 mg kg-1) than in Braçal (276–6175 mg kg-1). Cistus inflatus aerial parts contain higher concentrations of lead (49.5–217 mg kg-1) than Cistus ladanifer leaves (40.4–48.6 mg kg-1). Both Cistus, showing no external stress signals, are well adapted to these contaminated soils with low nutrient and high Pb contents. It is apparent that these plants can be used for phytostabilization in similar mining areas.
- Disponibilidade de Cu, Pb e Zn nas áreas mineiras de Canal Caveira e São Domingos - faixa piritosa IbéricaPublication . Santos, E.S.; Abreu, M.M.; Ferreira, M.B.; Magalhães, M.C.F.Several mining areas are abandoned in the Iberian pyrite belt (IPB) leading to important points of environmental contamination. The potential and immediate environmental risk and impact on public health of hazardous elements from soil can be estimated from availability analysis. The aim of this study was to evaluate the availability of Cu, Pb and Zn in São Domingos and Canal Caveira mining areas located in the IBP.
- Evaluation of amendments in the rehabilitation of sulfide mine tailings from São DomingosPublication . Abreu, M.M.; Varennes, A.; Santos, E.S.; Macias, F.The São Domingos mining area is located in the Iberian Pyrite Belt, SE Portugal, and represents a serious environmental hazard (Matos and Martins, 2006). Exploitation dated back to pre-roman and roman times with extraction of Ag, Au and Cu exploitation, mainly in the gossan (resulting from the ore weathering). The intense exploitation started in the middle of 19th century, both in the gossan and sulfide ore-containing Cu, Zn, As and Pb, and lasted until 1960, with the exhaustion of the ore (Quental et al., 2002). Different types of waste materials were left: gossan, host rocks (volcanic with shales, and shales), roman and modern slags, smelting ashes and brittle and blocks of pyrite (Matos, 2004; Álvarez-Valero et al., 2008). All sulfide mine wastes are typically heterogeneous and contain high amounts of trace elements, acidic pH and small contents of organic matter and nutrients. The large dumps containing pyrite and other metal sulfides generate, by oxidation, acidic mine drainage (AMD) which increases the availability of trace elements for microorganisms and plants in the surrounding soils. All of these characteristics contribute towards a system that is barely capable of supporting the establishment or survival of plants. The use of amendments and spontaneous colonization (vegetation) from mining areas (phytostabilization) are cost-effective and environmentally sustainable methods to rehabilitate these contaminated and degraded areas even in arid and semi-arid conditions (Tordoff et al., 2000; Mendez and Maier, 2008). Thus, the preparation of Technosols from mixtures of organic and inorganic wastes can be an attractive option to rehabilitate mining areas because they can improve physical, chemical and biological properties contributing, at the same time, towards a strategy of wastes valorisation (Macías, 2004). The use of mixtures composed of residues with different C:N ratios can be used to manipulate the rate of mineralization. Nevertheless, the amendments used should also promote other soil functions (Arbestain et al., 2008). The objective of this study was to evaluate the influence of cost-effective organic and inorganic amendments, available in the region, in the rehabilitation of sulfide materials from the São Domingos mine area