F. Macías

University of Santiago de Compostela, Santiago, Galicia, Spain

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Publications (127)218.68 Total impact

  • 12/2014; 15(ahead). DOI:10.4067/S0718-95162015005000006
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    ABSTRACT: La mina de Touro, está ubicada entre los municipios de O Pino y Touro, en la provincia de A Coruña, en la Comunidad Autónoma de Galicia, al Noroccidente de España. Fue explotada para la extracción de Cobre, a partir del yacimiento de sulfuros metálicos, definiendo las cortas de Bama, Brandelos, Arinteiro y Vieiro. Debido a la presencia de minerales como la pirita, pirrotina y calcopirita se generaron drenajes ácidos. Para la recuperación de la mina se desarrolló un proyecto innovador, aplicando el concepto de Tecnosoles "a la carta" y humedales reactivos. Estos Tecnosoles son diseñados técnicamente y elaborados a partir de residuos no peligrosos, con la finalidad de recuperar los suelos contaminados y las aguas ácidas. En la actualidad (2014) en la mina de Touro, la aplicación de los Tecnosoles han permitido que existan poblaciones animales y vegetales, así como también se han reducidos al mínimo las zonas con aguas ácidas.
    XX Congreso Latinoamericano y XVI Congreso Peruano de la Ciencia del Suelo, Cusco, Perú; 11/2014
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    ABSTRACT: The potentially hazardous effects of rock wastes disposed at open pit in three different areas (Pr: Ore processing; Wr: Waste rock and Bd: Border) of an abandoned copper mine were evaluated in this study, with emphasis on acid drainage generation, metal contamination and copper geochemical dynamics in soils. Samples of waste rock were analyzed by Energy dispersive X-ray fluorescence (XRF), scanning electron microscopy with microanalysis (SEM-EDS) and X-ray diffraction (XRD). Soil samples were analyzed to determine the total metal contents (XRF), mineralogy (XRD), pH (H2O and H2O2), organic and inorganic carbon, % of total N, S and P, particle size, and a sequential extraction procedure was used to identify the different copper fractions. As a result of the prevalence of carbonates over sulphides in the wastes, the soil pH remained close to neutral, with absence of acid mine drainage. The geochemical interaction between these mineral phases seems to be the main mechanism to release Cu(2)(+) ions. Total Cu in soils from the Pr area reached 11,180mg.kg(-1), while in Wr and Bd areas the values reached, on average, 4683 and 1086mg.kg(-1), respectively, indicating a very high level of soil contamination. In the Pr and Wr, the Cu was mainly associated with carbonates and amorphous iron oxides. In the Bd areas, the presence of vegetation has influenced the geochemical behavior of copper by increasing the dissolution of carbonates, affecting the buffer capacity of soils against sulphide oxidation, reducing the pH levels and enhancing the proportion of exchangeable and organic bound Cu. The present findings show that the use of plants or organic amendments in mine sites with high concentration of Cu carbonate-containing wastes should be viewed with caution, as the practice may enhance the mobilization of copper to the environment due to an increase in the rate of carbonates dissolution.
    Science of The Total Environment 09/2014; 500-501C:91-102. DOI:10.1016/j.scitotenv.2014.08.086 · 3.16 Impact Factor
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    ABSTRACT: Greenhouse pot experiments were conducted over 13 months to evaluate the effect of two amendment mixture doses (30 and 75 Mg/ha) on the geochemical dispersion of trace elements by leaching hazardous mine wastes from the São Domingos mine. Mineralogical evolution of these materials was also evaluated. Amendment mixtures containing solid wastes from agriculture (plant remains + strawberry substrate and rockwool used for the strawberry crop) and from distillation of Ceratonia siliqua L. and Arbutus unedo L. fruits were used to improve the chemical characteristics of leachates from sulfide mine wastes. Sulfide mine wastes had acidic characteristics, as well as high electrical conductivity and total element concentrations (g/kg; Al: 54.8–61.2; Fe: 104.0–110.0; Pb: 9.0–13.8; S: 63.6–68.0; As: ≈ 1). These features contributed to the large capacity for leaching of hazardous elements during, at least, the first four months of incubation. In the seventh month of incubation, there was a significant decrease in the leachate concentration of the majority of hazardous elements. The addition of amendments minimised trace element dispersion in leachate percolation during the first seven months (25 to 99% reduction compared to control, depending on the element and sampling period). However, the leachate characteristics were not influenced by amendment doses and no significant differences were observed in leachate composition (control and amended treatments) after 13 months. Amendment application led to differences between the solid phases of the efflorescent salts formed on the surface of the control and the amended treatments. The efflorescent salts contained very soluble aluminium sulfates, together with alunite–jarosite-group solid phases in amended samples, and copiapite-group solid phases in control. In the core materials (5 to 10 cm in depth), the mineralogy was similar in both control and amended samples. The presence of various stable solid phases from alunite–jarosite-group, such as jarosite and beudantite (mainly in deeper materials), can explain the low concentrations of trace elements in the leachates after thirteen months.
    Geoderma 08/2014; s 226–227:188–203. DOI:10.1016/j.geoderma.2014.02.004 · 2.51 Impact Factor
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    Bolaños D. R., Macías F.
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    ABSTRACT: 1. Introduction – The purpose of this research has been the application of Technosols as a complement to treatment of wastewater. The project was developed on a farm which has wine production, between 400000 and 600000 bottles per year, in addition, on weekends and holidays have social and cultural events with a maximum capacity of 350 people, generating specific increases for flows wastewater. According to the law, the Authority requires the treatment of the wastewater generated. In the area there is no public sewer system, so by mutual agreement specifies a point on a tributary to the river Umia. Treatment plant had a dosing chamber, which tries to maintain a constant flow into a digester fed by gravity settling tanks. Then the water goes to the first zone vertical flow wetland, and then goes to 3 horizontal flow wetlands. Above them were planted emergent macrophytes such as reeds (Phragmites), espadana (Typha) and bulrush (Scirpus), with a density of 3 units per square meter, all typical of wetlands. The control parameters detected early problems just start operation. Designers proposed expanding the size of the treatment plant, which is geometric and economically unfeasible. You could not have residual surface water due to the use of the farm hospitality. Neither can increase the area of wetlands, because the surrounding areas have other specific uses. According to the described problem, the main objective of the project was to contribute to the process of treatment of urban waste water by applying Technosols in horizontal flow wetlands. With previous successful experiences in which Technosols have served to improve water quality [1, 2, 3]. The proposal was to modify the configuration of the horizontal flow wetlands. For Tecnosol layer was applied, adding tifa type plants (Typha latifolia) and modified internal geometry to increase the path length and residence time, all this, in order to constantly evaluate the evolution of the parameters quality.
    International Congress on Water, Waste and Energy Management., Oporto, Portugal; 07/2014
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    Edited by Andavira Editorial, 06/2014; , ISBN: 978-84-8408-771-7
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    ABSTRACT: Se determinó la capacidad máxima de adsorción de fosfatos en un Tecnosol con propiedades ándicas. El Tecnosol fue diseñado, formulado y elaborado para reducir las concentraciones de P en sistemas acuáticos, contribuyendo a la reducción de la eutrofización y sus consecuencias nocivas. Después de seis meses sumergido en aguas del río Limia, la capacidad de adsorción del Tecnosol apena disminuyó. Por este motivo, se decidió realizar un ensayo de adsorción en laboratorio y someter el Tecnosol a ciclos de aporte de P. Para simular condiciones naturales en aguas eutrofizadas, los ensayos se realizaron con concentraciones de 1 mg.L-1, mientras que para monitorizar la respuesta a condiciones extremas se añadieron también dosis de 100 mg.L-1 en paralelo. Para contrastar el efecto que tuvo ese periodo sumergido en agua sobre el Tecnosol se utilizaron dos grupos de muestras: el Tecnosol usado y el mismo Tecnosol conservado sin uso. La máxima de adsorción del Tecnosol sin usar puede llegar a 7500 mg.kg-1.
    VI Congreso Ibérico del Suelo; 06/2014
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    ABSTRACT: Wastewater discharge from shrimp farming is one of the main causes of eutrophication in mangrove ecosystems. We investigated the phosphorus (P) geochemistry in mangrove soils affected by shrimp farming effluents by carrying out a seasonal study of two mangrove forests (a control site (CS); a site affected by shrimp farm effluents (SF)). We determined the soil pH, redox potential (Eh), total organic carbon (TOC), total phosphorus (TP), and dissolved P. We also carried out sequential extraction of the P-solid phases. In SF, the effluents affected the soil physicochemical conditions, resulting in lower Eh and higher pH, as well as lower TOC and higher TP than in CS. Organic P forms were dominant in both sites and seasons, although to a lesser extent in SF. The lower TOC in SF was related to the increased microbial activity and organic matter decomposition caused by fertilization. The higher amounts of P oxides in SF suggest that the effluents alter the dominance of iron and sulfate reduction in mangrove soils, generating more reactive Fe that is available for bonding to phosphates. Strong TP losses were recorded in both sites during the dry season, in association with increased amounts of exchangeable and dissolved P. The higher bioavailability of P during the dry season may be attributed to increased mineralization of organic matter and dissolution of Ca-P in response to more oxidizing and acidic conditions. The P loss has significant environmental implications regarding eutrophication and marine productivity.
    Environmental Monitoring and Assessment 05/2014; 186(9). DOI:10.1007/s10661-014-3817-3 · 1.68 Impact Factor
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    ABSTRACT: The aim of this study was to identify metal-tolerant plants with potential application in phytoremediation strategies. For this we evaluated the distribution and chemical fractionation of heavy metals in soils and their accumulation or exclusion by native plant species growing in an abandoned Pb/Zn mine in NW Spain. Mine-soils (I = 0–20 cm, II = 20–40 cm) and shoots of the dominant plants were sampled at 39 sampling points in a (100 m × 100 m) regular grid at two sites (mine zone (MZ) and tailing ponds (TP)). Total metal contents in mine-soils presented a high heterogeneity and the principal contaminants were Cd, Hg, Pb and Zn (in agreement with the mineralogy of the site). Total concentrations varied from 2 to 95 mg Cd kg−1, 0.2 to 24.8 mg Hg kg−1, 46 to 6100 mg Pb kg−1, and 340 to 52,000 mg Zn kg−1. Soil metal distribution did not vary significantly with depth, but total and EDTA-extractable metal concentrations were higher in MZ than TP. On the other hand, the relative extractability of soil metals (EDTA-extractable concentration expressed as a % of total concentration) was higher in TP. The residual fraction was dominant for Co, Cr, Cu, and Ni, representing generally more than 50% of total concentration. Pb was preferentially associated with the oxidisable fraction, followed by the acid-extractable fraction. Both Cd and Zn were amply represented by the oxidisable, reducible and acid-extractable fractions. All the studied plant species were metal-tolerant (pseudometallophytes), although differences were found between species. Significant differences were found in plant accumulation of Cd and primarily, Zn. Cytisus scoparius and C. multiflorus were efficient metal-excluding species, and could be interesting candidates for phytostabilisation techniques and/or revegetation of heavily contaminated soils. Salix atrocinerea, presented significantly higher concentrations of Zn in its aerial biomass (543 ± 108 mg Zn kg−1) than the remaining species and bioconcentration factors (BCF) of up to 2.35 for Zn and 4.17 for Cd, respectively. This population could be interesting in the phytoextraction of low to moderately-contaminated soils.
    Applied Geochemistry 05/2014; 44:3–11. DOI:10.1016/j.apgeochem.2013.09.001 · 2.02 Impact Factor
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    Bolaños D. R., Macías F.
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    ABSTRACT: The purpose of this investigation was to test the application of Technosols for the prevention of contamination by slate. The excavation of materials, soil or rock, generates transport, treatment and disposal of material to another location, which will inevitably alter the relief, affecting air, species composition and even the water cycle. Both the exploration and exploitation of slate materials are frequent adverse effects on water, among which are increased acidity, concentration of pollutants (sulfates and potentially toxic metals and metalloids) and solid particles in cases discharge. The geology of Galicia has a large presence of slate with many variations due to the composition of the strata. Among the different types of items that may become mobilized shale holdings some potentially very dangerous, among which we highlight the Arsenic, Copper, Nickel, Manganese, Chromium and Vanadium. The research group has implemented several projects Technosols application. These have allowed the concept and application area, evolve from remediation projects until the current ones, which are intended to prevent pollution episodes. The common criterion is that the immobilized Technosol elements and compounds, potentially polluting. The hypothesis states take an evolutionary step in implementing Technosols now directed to use in preventing contamination of some potentially hazardous elements in conjunction with the slates of the geology of Galicia and avoid the presence of acid mine drainage. Waste in the exploitation of shale are analyzed. Of these, those that present the greatest potential risk are chosen, and necessarily need to be treated. Will take them to a specific area for this purpose. Monitoring the effect of Technosol, will be performed by analyzing samples of water leaving the treatment. Thus, we can distinguish two types of samples, rocks and water. The initial results of the study presented in this article, are positive, however it should be mentioned that monitoring, behavior Technosol, will run for at least the next 4 years.
    II International AFRICA Sustainable Waste Management Conference, Luanda, Angola; 04/2014
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    ABSTRACT: Gossan wastes represent one of the most hazardous mine wastes in several mining areas from the Iberian Pyrite Belt. Phytostabilization of mine wastes with Cistus ladanifer L. could be a good option, but its growth and germination are impaired by substrata conditions. To overcome these limitations, application of organic and inorganic amendments may speed up the growth of C. ladanifer while improving the mine wastes. This study evaluated the simultaneous influence of different application rates of amendments and growth of C. ladanifer on chemical and biological properties of gossan wastes. Amendments used were mixtures (30, 75, 150 Mg/ha, 1:1:1) of rockwool, agriculture wastes and wastes from liquor distillation of Arbutus unedo L. fruits. A microcosm assay with four treatments was carried out (control and three amended treatments) under controlled conditions in a greenhouse during 505 days. C. ladanifer was sown in half of the pots from each treatment while the remainder was left bare. Gossan wastes had large total concentrations of several elements (g/kg; Al: 24.8, As: 3.03, Cu: 0.23, Pb; 9.21) whereas the available concentrations of these elements were small (< 5.7 % of total). The amendments applied (in particular at 75 and 150 Mg/ha) improved the structure and increased the water-holding capacity, pH and nutrients concentrations in the available fraction of the gossan materials. They also led to increases in dehydrogenase and β-glucosidase activities and in plant growth (plant cover, plant height, length of young leaves, fresh biomass). In addition, plants from amended treatments presented lower concentrations of hazardous elements in shoots than plants from unamended control. The presence of the plant did not increase the available concentrations of hazardous elements in wastes, except for As when 150 Mg/ha of amendments were applied. Phytostabilization with C. ladanifer using a Technosol, resulting from the application of the studied amendments at 75 and 150 Mg/ha to gossan materials seems a promising solution for rehabilitation of this type of mine wastes.
    Journal of Geochemical Exploration 04/2014; DOI:10.1016/j.gexplo.2014.07.007 · 2.43 Impact Factor
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    ABSTRACT: Los problemas de calidad del agua tienen su origen en diferentes actividades como: industria, minería, aguas residuales urbanas o agricultura, entre otras. En todas ellas se evidencia el desequilibrio producido por las actividades antrópicas, que, en muchas ocasiones, queda abandonado a soluciones de atenuación natural, de acuerdo a los componentes minerales de los materiales geológicos, la actividad biológica y el papel de filtro, reactor, reactivo y sistema tamponizante de los suelos y las condiciones hidráulicas que regulan la concentración de oxidantes o los procesos de sedimentación, ente otros efectos. Este sistema de depuración natural es, en muchos casos, insuficiente para lograr la recuperación de la calidad de las aguas en el espacio y tiempo necesario, especialmente cuando se supera la carga crítica de contaminantes del sistema suelo-agua. Los Tecnosoles son suelos, que pueden ser diseñados técnicamente (Tecnosol "a la carta"), para reforzar la capacidad de atenuación de los sistemas naturales, corregir las disfunciones existentes y aumentar la capacidad de amortiguación y la carga crítica de contaminantes del sistema suelo-agua afectado. Con estos antecedentes, el grupo de investigación ha ejecutado distintos proyectos con aplicación de Tecnosoles para recuperar aguas, suelos y ecosistemas afectados por diferentes tipos de procesos contaminantes. Se hace mención aquí de tres tipos de procesos con diferentes Tecnosoles en los que se han conseguido buenos resultados: • Drenajes Ácidos de Mina • Eutrofización • Aguas Residuales Las conclusiones de los distintos estudios han servido para ampliar el campo de acción de esta línea de investigación sobre Tecnosoles en espacios contaminados. Palabras claves: calidad de agua, tecnosol "a la carta".
    12° Congreso da Água y 16° Encontro de Engenharia Sanitária e Ambiental (ENASB), Lisboa, Portugal; 03/2014
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    Bolaños D. R., Macías F.
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    ABSTRACT: The purpose of this investigation was to test the application of Technosols for the treatment of eutrophication by capturing phosphates from eutrophic water bodies, thereby preventing or reducing the intensity of cyanobacterial blooms. A Technosol designed specifically for phosphate adsorption was placed into permeable bags to allow contact with water. These bags were mounted onto three parallel plates on a steel structure to cover the largest possible area of the riverbed. Two tributaries of the As Conchas reservoir were chosen because of their nutrient levels. The locations of the treatment structures were determined based on their accessibility to equipment and machinery. After placement, the effect of Technosol on water quality was monitored in samples taken upstream and downstream of the point of contact with the Technosol. This study obtained the first data regarding the behavior of an experimental Technosol, designed for a specific purpose (called Technosol "a la carte," or tailor-made Technosol), e.g., for the treatment of eutrophication in field conditions. The results demonstrate Technosol's high capacity for decreasing eutrophication: phosphate concentrations were reduced after contact with the Technosol, and during the implementation period, there were no cyanobacterial blooms at the As Conchas dam downstream of the test sites.
    International Perspective for Water and Environment IPWE 2014. Organizado por la ASCE American Society of Civil Engineers y el EWRI Environmental and Water Resources Institute.; 01/2014
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    ABSTRACT: En Chile, la agricultura y la ganadería son actividades productivas económicamente importantes, representando el 4,5% del Producto Interno Bruto (PIB) en conjunto con el sector forestal. A nivel mundial se estima que las actividades agropecuarias son la principal fuente de emisiones gaseosas de amoníaco (NH3) a la atmósfera, siendo la aplicación de fertilizantes nitrogenados a praderas, ya sea de origen mineral u orgánico, una de las principales fuentes de emisión. Las emisiones de NH3 han sido vinculadas con importantes impactos ambientales; sin embargo, a pesar de la importancia de estas emisiones, existen pocos datos publicados con respecto a los factores que afectan la generación de las mismas en praderas del sur de Chile. La fertilización es una práctica común en el sur del país, donde la mayoría de los sistemas de producción agropecuarios están basados casi exclusivamente en el uso de las praderas permanentes como fuente de alimentación animal a lo largo de todo el año. El objetivo de esta revisión fue analizar los factores que pueden afectar la generación de las emisiones de NH3 luego de la aplicación de urea y purín de lechería a praderas permanentes en Andosoles del sur de Chile. Los resultados indican que los principales factores que pueden afectar la magnitud de las pérdidas de N por volatilización de NH3 son las variables climáticas, las condiciones de la pradera/suelo y el manejo de la fertilización, existiendo opciones para la reducción de las emisiones amoniacales que contribuyen a mejorar la eficiencia de uso del N aplicado a la vez que minimizan el riesgo de contaminación ambiental.
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    ABSTRACT: A semi-arid mangrove estuary system in the northeast Brazilian coast (Ceará state) was selected for this study to (i) evaluate the impact of shrimp farm nutrient-rich wastewater effluents on the soil geochemistry and organic carbon (OC) storage and (ii) estimate the total amount of OC stored in mangrove soils (0–40 cm). Wastewater-affected mangrove forests were referred to as WAM and undisturbed areas as Non-WAM. Redox conditions and OC content were statistically correlated (P b 0.05) with seasonality and type of land use (WAM vs. Non-WAM). Eh values were from anoxic to oxic conditions in the wet season (from −5 to 68 mV in WAM and from b40 to N 400 mV in Non-WAM soils) and significantly higher (from 66 to 411 mV) in the dry season (P b 0.01). OC con-tents (0–40 cm soil depth) were significantly higher (P b 0.01) in the wet season than the dry season, and higher in Non-WAM soils than in WAM soils (values of 8.1 and 6.7 kg m −2 in the wet and dry seasons, respectively, for Non-WAM, and values of 3.8 and 2.9 kg m −2 in the wet and dry seasons, respectively, for WAM soils; P b 0.01). Iron partitioning was significantly dependent (P b 0.05) on type of land use, with a smaller degree of pyritization and lower Fe-pyrite presence in WAM soils compared to Non-WAM soils. Basal respiration of soil sediments was significantly influenced (P b 0.01) by type of land use with highest CO 2 flux rates measured in the WAM soils (mean values of 0.20 mg CO 2 h −1 –g −1 C vs. 0.04 mg CO 2 h −1 –g −1 C). The OC storage reduction in WAM soils was potentially caused (i) by an increase in microbial activity induced by loading of nutrient-rich effluents and (ii) by an increase of strong electron acceptors [e.g., NO 3 − ] that promote a decrease in pyrite concentration and hence a reduction in soil OC burial. The current estimated OC stored in mangrove soils (0–40 cm) in the state of Ceará is approximately 1 million t.
    Geoderma 01/2014; 213:551-559. DOI:10.1016/j.geoderma.2013.08.007 · 2.51 Impact Factor
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    ABSTRACT: Bacterial and archaeal community structures and diversity of three different sedimentary environments (BH1A, BH2A and BH3A) in the acid pit lake of a chalcopyrite mine at Touro (Spain) were determined by 16S rRNA gene PCR-DGGE and sequencing of clone libraries. DGGE of bacterial and archaeal amplicons showed that the sediments harbor different communities. Bacterial 16S rRNA gene sequences were assigned to Acidobacteria, Actinobacteria, Cyanobacteria, Planctomycetes, Proteobacteria, Chloroflexi and uncultured bacteria, after clustering into 42 operational taxonomic units (OTUs). OTU 2 represented approximately 37, 42 and 37 % of all sequences from sediments BH1A, BH2A and BH3A, respectively, and was phylogenetically related to uncultured Chloroflexi. Remaining OTUs were phylogenetically related to heterotrophic bacteria, including representatives of Ferrithrix and Acidobacterium genera. Archaeal 16S rRNA gene sequences were clustered into 54 OTUs. Most of the sequences from the BH1A sediment were assigned to Euryarchaeota, whereas those from BH2A sediment were assigned to Crenarchaeota. The majority of the sequences from BH3A sediment were assigned to unclassified Archaea, and showed similarities to uncultured and unclassified environmental clones. No sequences related to Acidithiobacillus and Leptospirillum, commonly associated with acid mine drainage, were detected in this study.
    Extremophiles 08/2013; 17(6). DOI:10.1007/s00792-013-0576-y · 2.17 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate the chemical characteristics and ecotoxicity of a mine soil developed on gossan materials and amended with hydrophilic polyacrylate polymers after a growth cycle of Spergularia purpurea. Different acute bioassays (Daphnia magna immobilization; microalgae growth inhibition; germination and growth of lettuce and oat) were carried out with simulated leachates, pore water and soil samples. The germination and growth of native shrubs (Cistus ladanifer and Lavandula sampaioana) were also evaluated in the lysimeters where S. purpurea had grown. The soil had high total concentrations (g/kg) of Al (3.50-8.60), As (2.55-2.73), Cu (0.13-0.91) and Pb (4.48-6.16). However, the percentages of elements in aqueous extracts (simulating leachates, pore water, and the conditions of the rhizosphere soil) were small when compared to their total soil concentrations (less than 9% except for Na in leachates). Growth of S. purpurea and other natural colonization of plant species (Poaceae, Fabaceae and Asteraceae families) improved chemical characteristics but the application of the polyacrylate polymers contributed to a further improvement of soil quality. However, this was not sufficient to ensure the growth of a large number of shrubs despite a great germination rate. Among the several species used on the ecotoxicological assessment, the D. magna test was the only bioassay that showed a clear toxicity of soil leachates, suggesting the importance of using several ecotoxicological tests to assess the environmental risk of soil contamination and its rehabilitation. Although the studied soil can be considered contaminated taking into account the total soil concentrations of Al, As, Cu and Pb, the low concentrations of the same chemical elements in extractable solutions, that simulated the fractions really available for organisms, did not demonstrate a substantial toxic effects in the organisms and, consequently, negative impact on the environment.
    Science of The Total Environment 06/2013; 461-462C:360-370. DOI:10.1016/j.scitotenv.2013.05.003 · 3.16 Impact Factor
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    ABSTRACT: Climatic conditions of subtropical and tropical regions support fast carbon (C) mineralization, and thus an accelerated degradation of soil organic matter (SOM) if compared to temperate region (Sánchez & Logan, 1992). However, even in those regions, there are still soil horizons that show notable C accumulation. Examples for the latter are umbric horizons in typical tropical soils, such as Ferralsols. The occurrence of this soils with thick umbric epipedons (× 100 cm thickness) in areas of South Brazil is a paradox, that still needs a better understanding (Marques et al., 2011), in particular since the processes that are responsible for the thickness and darkness of the umbric horizons are of special interest with respect to the role of soils as carbon sink. One major contributor to SOM stabilization represents the soil mineral phase. Therefore the main goal of this work its to study the impact of this factor on the SOM sequestration in Umbric Ferralsols from Atibaia, Campinas (São Paulo State) and Chapecó (Santa Catarina State) developed under different environmental conditions. With this objective the mineral fractions have been isolated by selective extraction of iron and aluminium oxides with different extracting solutions (sodium pyrophosphate, ammonium oxalate and dithionite-citrate-bicarbonate solution) and related to SOM quality and quantity. The latter was studied by the use of solid-state cross polarisation (CPMAS) 13C NMR spectroscopy after demineralization with hydrofluoric acid (Gonçalves et al., 2003). Quantification of the NMR spectra was performed by integration of the respective chemical shift regions under consideration of the contribution of spinning side bands. For our study the following regions were distinguished (Knicker & Lüdemann, 1995): alkyl C (0-45 ppm), N-alkyl C (45-60ppm), O-alkyl C (60-110 ppm), aryl C (110-160 ppm), carbonyl C (160-245 ppm). Preliminary results show that, the minimum vertical variation of total Fe into the profile is classical in Ferralsols and the behavior of Al points to the high presence of gibbsite in the clay fractions of the deeper horizon of the Campinas soils. The (AlP+FeP)/C ratios, obtained after extraction of the Al and Fe forms with a sodium pyrophosphate solution, were above 0.03 throughout the studied profile. According to Nierop et al. (2002) this points towards the existence of organic-metallic compounds. Most tentatively, they precipitated due to saturation of adsorption site. The solid-state 13C NMR spectra of the Chapecó samples showed that the preserved organic C is dominated by a alkyl C in lipids and amino acids (45 - 0 ppm). Other major intensities are observed between 110 and 45 ppm, in the region of O/N-alkyl C (carbohydrates, amino acids) and carboxyl C (220 to 160 ppm). The missing of a clear signal in the region between 160 and 110 ppm (signal derives from aromatic or olefinic C) indicates that in this soil lignin has minor contributions to its aromatic C content.
    EGU General Assembly 2013, Vienna, Austria; 04/2013
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    ABSTRACT: The soil organic matter (SOM) extracted under different vegetation types from a Brazilian mangrove (Pai Matos Island, São Paulo State) and from three Spanish salt marshes (Betanzos Ría and Corrubedo Natural Parks, Galícia, and the Albufera Natural Park, Valencia) was investigated by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The chemical variation was larger in SOM from the Spanish marshes than in the SOM of the Brazilian mangroves, possibly because the marshes included sites with both tidal and nontidal variation, whereas the mangrove forest underwent just tidal variation. Thus, plant-derived organic matter was better preserved under permanently anoxic environments. Moreover, given the low number of studied profiles and sedimentary¿vegetation sequences in both areas, depth trends remain unclear. The chemical data also allow distinction between the contributions of woody and nonwoody vegetation inputs. Soil organic matter decomposition was found to cause: (i) a decrease in lignin contents and a relative increase in aliphatics; (ii) an increase in short-chain aliphatics at the expense of longer ones; (iii) a loss of odd-over-even dominance in alkanes and alkenes; and (iv) an increase in microbial products, including proteins, sterols, short-chain fatty acids, and alkanes. Pyrolysis-gas chromatography/mass spectrometry is a useful tool to study the behavior and composition of SOM in wetland environments such as mangroves and salt marshes. Additional profiles need to be studied for each vegetation type, however, to improve the interpretability of the chemical data
    Soil Science Society of America Journal 02/2013; Ferreira, Fernando Perobelli(73):841-851. DOI:10.2136/sssaj2008.0028 · 2.00 Impact Factor
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    ABSTRACT: The analysis of phytolith assemblages is an important method in studies that uses the soil as an environmental record in order to reconstruct the paleoclimatic conditions. Despite being underused in soil science, this technique is used complementary to the analysis of pollen and other microfossils, as well as to evaluate silicon reserves in the soil. Currently, there are several concentration methods for phytolith extraction from sediments, soils, and paleosols. Most were developed and applied to materials of temperate zones or hydromorphic environments. Few have been conducted in tropical soils where oxides and hydroxides of iron and aluminum, as well as organic matter that often blankets the soil matrix, are common and hamper the extraction, the observation and identification of phytoliths, compromising the morphological analysis and quantification of phytolith assemblage in soils. In this paper, three methods of pre-treatment for the removal of the coating of silt and sand particles were applied to samples of an Oxisol (Humic Hapludox) in order to compare the cleaning efficiency, integrity and number of phytoliths. The first method consisted of the oxidation of soil organic matter and of an acid hydrolysis for the removal of carbonates and oxides. In the second method, the dominant process was the reduction of iron using a combination Dithionite-Citrate-Sodium Bicarbonate. In the third method, only acetate and sodium dithionite dissolved in water was used. Overall, Method 1 was the most aggressive to phytoliths and proved less efficient and more selective in phytolith extraction. Methods 2 and 3 were similar in the pre-treatment of samples. Method 2 allows the conservation of greater variety and number of phytoliths, and smaller quantities of other particles. Method 3 is relatively inexpensive and faster because it uses fewer chemicals and centrifugation procedures.
    Quaternary International 02/2013; 287:56-62. DOI:10.1016/j.quaint.2011.11.005 · 2.13 Impact Factor

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1k Citations
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Institutions

  • 1987–2014
    • University of Santiago de Compostela
      • • Faculty of Biology
      • • Department of Edafology and Agricultural Chemistry
      • • Área de Edafología y Química Agrícola
      • • High Technical College
      • • Departamento de Estomatología
      Santiago, Galicia, Spain
  • 1998–1999
    • Santiago University of Technology
      Santiago, Santiago, Dominican Republic