Ondra Sracek

Palacký University of Olomouc, Olmütz, Olomoucký, Czech Republic

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Publications (78)152.58 Total impact

  • Applied Geochemistry 08/2015; DOI:10.1016/j.apgeochem.2015.07.006 · 2.02 Impact Factor
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    ABSTRACT: The contents of As, Cu, Cd, Pb, Mn, along with the Pb isotopic ratios 206Pb/207Pb and 208Pb/206Pb were studied in both soils and tree rings of the marula tree (Sclerocarya birrea) in the vicinity of the Tsumeb deposit (Namibia). Amounts of all the studied metals and As are higher in the immediate vicinity of the Tsumeb Cu-Pb smelter in the soil. The tree rings also have their maximum content of all the studied substances in the vicinity of the smelter (with the exception of Pb). At a more distant site, the maximum concentration of Pb in the soils was 29.8 mg/kg, while the content in the soil in the vicinity of the smelter was as much as 8,174 mg/kg. In the vicinity of the smelter, the maximum Pb content in the tree rings reaches a value of 5.7 mg/kg, compared to a more distant site, where the contents are as high as 9.2 mg/kg. The lower Pb content in the trees on contaminated soil indicates that the composition of the xylem determines the above-ground uptake, rather than the root uptake. Similarly, the above-ground uptake is documented by the isotopic composition of Pb at the distant location, where the tree rings have different contents of Pb isotopes compared to in the soil. The As, Cd, Cu, Pb, and Zn contents are highest in the tree rings from the 1950s (and older), along with those from the 1990s, while the Mn contents were highest in those from the 1960s and 1990s. The contaminant peaks in the 1950s and 1960s could be associated with the roasting of sulfidic ores, while the peak values in the 1990s could have been caused by the start of Cu slag reprocessing in the late 1980s, and culmination of works at the smelter prior to the closing of the mine. The tree rings of the marula tree were found to be a suitable archive for above-ground pollution close to Cu and Pb smelters.
    Water Air and Soil Pollution 06/2015; 226(6). DOI:10.1007/s11270-015-2440-4 · 1.69 Impact Factor
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    ABSTRACT: Mine tailings at Rosh Pinah located in semiarid southern Namibia were investigated by the combination of mineralogical methods and leaching using water and simulated gastric solution. They are well-neutralized with leachate pH > 7 and neutralization potential ratios (NPR) up to 4. Neutralization is mainly due to abundant Mn-rich dolomite in the matrix. Concentrations of released contaminants in water leachate follow the order Zn > Pb > Cu > As. Relatively high leached concentrations of Zn and partly also of Pb are caused by their link to relatively soluble carbonates and Mn-oxyhydroxides. In contrast, As is almost immobile by binding into Fe-oxyhydroxides, which are resistant to dissolution. Barium is released by the dissolution of Ba-carbonate (norsethite) and precipitates in sulfate-rich pore water as barite.
    Journal of African Earth Sciences 05/2015; 105. DOI:10.1016/j.jafrearsci.2015.02.005 · 1.38 Impact Factor
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    ABSTRACT: Numerous hot springs and fumaroles occur along the Andes Mountains, in the Bolivian Altiplano, where people use thermal springs for recreational purposes as pools, baths and also for consumption as drinking water and irrigation once it is mixed with natural surface waters; most of these thermal springs emerge from earth surface and flow naturally into the rivers streams which drain further into the Poopó Lake. Physicochemical characteristics of the thermal water samples showed pH from 6.3 to 8.3 with an average of 7.0, redox potential from +106 to +204 mV with an average of +172 mV, temperatures from 40 to 75°C with an average of 56°C and high electrical conductivity ranging from 1.8 to 75 mS/cm and averaged 13 mS/cm. Predominant major ions are Na+ and Cl- and the principal water types are 37.5 % Na-Cl type and 37.5 % Na-Cl-HCO3 type. Arsenic concentrations ranged from 7.8 to 65.3 μg/L and arsenic speciation indicate the predominance of As(III) species. Sediments collected from the outlets of thermal waters show high iron content, and ferric oxides and hydroxides are assumed to be principal mineral phases for arsenic attenuation by adsorption/co-precipitation processes. Arsenic concentrations in cold water samples from shallow aquifers are higher than those in thermal springs (range < 5.6 to 233.2 μg/L), it is likely that thermal water discharge is not the main source of high arsenic content in the shallow aquifer as they are very immature and may only have a small component corresponding to the deep geothermal reservoir. As people use both thermal waters and cold waters for consumption, there is a high risk for arsenic exposure in the area.
    Journal of South American Earth Sciences 03/2015; 60. DOI:10.1016/j.jsames.2015.02.006 · 1.36 Impact Factor
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    ABSTRACT: The arsenic mineralization in historical waste rock pile at Kaňk site near Kutná Hora developed over a period of about 500 years. The objective of this study was to determine principal secondary arsenic mineral phases and their environmental stability. The only common primary As-bearing mineral – arsenopyrite - occurs in the mineral assemblage of Kutná Hora base-metal deposit together with quartz, pyrite, sphalerite, and pyrrhotite. Most of arsenic is bound in supergene minerals (scorodite, jarosite-beudantite, bukovskýite, pitticite), which are relatively stable under oxidizing conditions prevailing in the pile. The Kaňk site is a type locality for bukovskýite, kaňkite, zýkaite, and parascorodite. In long-term perspective, the most stable minerals from viewpoint of As-binding appear to be scorodite and beudantite. A higher mobility was observed for As incorporated into jarosite and poorly crystalline to amorphous phases (FeIII -oxyhydroxides, pitticite). This study has not confirmed significant mobility of arsenic within the pile and water infiltrating in recharge periods of the year (late winter-early spring) should not mobilize arsenic at a significant rate. However, monitoring of the stability of secondary As-phases and dissolved arsenic in the environment around the pile is required to avoid future migration of arsenic out of the pile.
    Mineralogy and Petrology 02/2015; 109(1). DOI:10.1007/s00710-014-0356-0 · 1.60 Impact Factor
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    David Krčmář · Ondra Sracek
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    ABSTRACT: Geological heterogeneity associated with layers, open mine voids, tectonic faults and fractures can all make modelling difficult, particularly for mine dewatering. This heterogeneity is difficult to represent with the traditional MODFLOW structured grid. A new version of MODFLOW, called MODFLOW-USG (for UnStructured Grid), supports a wide variety of structured and unstructured grid types (Panday et al. in MODFLOW-USG version 1: an unstructured grid version of MODFLOW for simulating groundwater flow and tightly coupled processes using a control volume finite-difference formulation. USGS, Reston, 2013) that provide flexibility for modelling difficult geologic structures. This communication compares aspects of MODFLOW and MODFLOW-USG, and uses the Gbely lignite deposit as an example of a situation for which MODFLOW-USG could be applied.
    Mine Water and the Environment 12/2014; DOI:10.1007/s10230-014-0273-9 · 1.20 Impact Factor
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    ABSTRACT: Summary We present here major ion, trace element, stable and radioisotope data based on forty-six groundwater samples collected from various locations along few selected profiles across the Chianan Plain, southwestern Taiwan including the area affected by well known Blackfoot disease manifested by peripheral vascular gangrene. The objective of the study was to understand the role of local hydrogeology in terms of spatial variation of arsenic concentration in groundwater wells of the entire Chianan Plain and the foothill belt of the Central Mountain Range. An attempt has also been made to assess the contribution of nearby geothermal sources to the arsenic budget in groundwater of the Chianan Plain. Our study shows a gradual increase in all major and trace ion concentrations including total arsenic from foothill belt (arsenic: median = 4 μg/L, range = 0–667.6 μg/L, sample number n = 16) to coastal zones (arsenic: median = 42.74 μg/L, range = 0.14–348.6 μg/L, n = 15) of the plain. Inverse geochemical modeling shows that Ca may be exchanged on clays, and that the degree of the exchange increases from the foothill to the coastal zones. Inverse geochemical modeling further suggests that the oxidation of organic matter (CH2O) required in various east-west profiles across the plain to balance the total bicarbonate concentration and CO2 input from organic matters significantly increases from the foothill to the coastal zones with transfer coefficients ranging from 1.55 × 10−2 to 1.69 × 10−5 mol/L. High concentrations of tritium (mean = 1.33 ± 0.11 TU; n = 4) in foothill groundwater and low concentration of tritium in groundwater of central zone suggest gradually increasing water–rock interaction from the foothill to the coastal part. Few elevated arsenic (median = 171.8 μg/L, maximum = 667.60 μg/L, minimum = 24 μg/L; n = 6) hotspots are identified in the foothill belt. Available lithologs and aquifer test data suggest that the presence of impermeable clay around those pockets possibly inhibits vertical and lateral flushing of the aquifer and aids strong water–rock interactions subsequently leading to release of arsenic into groundwater. Using oxygen isotope and chloride mass balance method, we estimated that geothermal sources can recharge a maximum of 4% of groundwater in proximal aquifers and contribute <2% of average As concentration in the groundwater of Chianan Plain. Our preliminary observations thus show some arsenic enrichment in foothill aquifers, providing a necessity of detailed study of the aquifer systems in these understudied regions. Moreover, our research indicates that the contribution of arsenic from geothermal sources is insignificant, which stands in contrast to earlier studies suggesting that mud volcanoes and thermal springs in the Western Foothill Belt of the Central Mountain Range were potential sources of groundwater arsenic in the Chianan Plain aquifers.
    Journal of Hydrology 10/2014; 518, Part C:393 - 409. DOI:10.1016/j.jhydrol.2014.03.067 · 3.05 Impact Factor
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    ABSTRACT: A geochemical approach was applied to understand the factors controlling the mobilization of As and trace elements (TEs) in mining areas of the Poopó and Antequera River sub-basins on the Bolivian Altiplano. A total of 52 samples (surface, groundwater and geothermal water) were collected during the rainy season (2009). Arsenic, Cd and Mn concentrations exceed World Health Organization (WHO) drinking water guidelines and Bolivian regulations for drinking water in 28 groundwater samples, but Cu, Ni, Pb and Zn do not. Arsenic, Cd, Mn, Pb and Zn concentrations exceed World Health Organization guidelines for drinking water and Bolivian regulations Class A standard for discharge to water bodies in 20 surface water samples, whereas levels of Cu do not, and Ni and Fe rarely exceed regulation and guideline values. Factor analysis was applied to 18 hydrochemical parameters of 52 samples. Five factors for groundwater (plagioclase weathering, dissolution of gypsum and halite, TEs mobilization at acidic pH, sulfide oxidation, and release of As) account for 86.5% of the total variance for Antequera and 83.9% for Poopó sub-basins. Four factors for surface water data (weathering and mobilization of TEs influenced by pH, dissolution of evaporate salts, neutralization of acid mine drainage, and As release due to dissolution of Mn and Fe oxides) account for 91% of the total variance in Antequera and 96% in Poopó sub-basins. The As and TEs mobilized in these regions could affect the local water sources, which is a prevalent concern with respect to water resource management in this semi-arid Altiplano region. Presence of both natural and anthropogenic sources of contamination requires careful monitoring of water quality.
    Journal of Hydrology 09/2014; 518. DOI:10.1016/j.jhydrol.2014.08.019 · 3.05 Impact Factor
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    ABSTRACT: Vanadium-rich mine tailings at Berg Aukas, site with a world-known vanadium mineralization in northeastern Namibia, were investigated using a combination of solid phase and mineralogical analyses, leaching tests and speciation modeling. Principal objective of the study was to determine, if vanadium can be released into the environment. In spite of >30 y of weathering and oxidation of tailings material to a maximum sampling depth of 2.4 m, a large portion of V still remains in the primary mineral descloizite, (Pb,Zn)2(OH)VO4. A part of V was mobilized and adsorbed/co-precipitated with ferric oxyhydroxides. Based on sequential extraction and 57Fe Mössbauer spectroscopy, a large amount of ferric iron is present in insoluble hematite and goethite, where V is effectively bound. Other potential contaminants are Zn, present mostly in the primary mineral willemite, Zn2SiO4, descloizite and also in secondary smithsonite, ZnCO3; and Pb, which was transferred from completely dissolved galena to cerussite, PbCO3 and is also partly present in primary descloizite. Conditions in the mine tailings are alkaline (pH generally >8.2) and oxidizing during dry period, but mobility of V is low due to low solubility of descloizite and secondary crystalline ferric phases such as hematite. In contrast, Zn and especially Pb in secondary carbonates, probably represent more serious environmental and health risks.
    Journal of African Earth Sciences 08/2014; 96. DOI:10.1016/j.jafrearsci.2014.04.003 · 1.38 Impact Factor
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    ABSTRACT: Exploitation of groundwater from shallow, high prolific Holocene sedimentary aquifers has been a main element for achieving safe drinking water and food security in Bangladesh. However, the presence of elevated levels of geogenic arsenic (As) in these aquifers has undermined this success. Except for targeting safe aquifers through installations of tubewells to greater depth, no mitigation option has been successfully implemented on a larger scale. The objective of this study has been to characterise the hydrostratigraphy, groundwater flow patterns, the hydraulic properties to assess the vulnerability of low-arsenic aquifers at Matlab, in south-eastern Bangladesh, one of the worst arsenic-affected areas of the country. Groundwater modelling, conventional pumping test using multilevel piezometers, hydraulic head monitoring in piezometer nests, 14C dating of groundwater and assessment of groundwater abstraction were used. A model comprising of three aquifers covering the top 250 m of the model domain showed the best fit for the calibration evaluation criteria. Irrigation wells in the Matlab area are mostly installed in clusters and account for most of the groundwater abstraction. Even though the hydraulic heads are affected locally by seasonal pumping, the aquifer system is fully recharged from the monsoonal replenishment. Groundwater simulations demonstrated the presence of deep regional flow systems with recharge areas in the eastern, hilly part of Bangladesh and shallow small local flow systems driven by local topography. Based on modelling results and 14C groundwater data, it can be concluded that the natural local flow systems reach a depth of 30 m b.g.l. in the study area. A downward vertical gradient of roughly 0.01 down to 200 m b.g.l. was observed and reproduced by calibrated models. The vertical gradient is mainly the result of the aquifer system and properties rather than abstraction rate, which is too limited at depth to make an imprint. Although irrigation wells substantially change local flow pattern, targeting low-As aquifers seems to be a suitable mitigation option for providing people with safe drinking water. However, installing additional irrigation- or high capacity production wells at the same depth is strongly discouraged as these could substantially change the groundwater flow pattern. The results from the present study and other similar studies can further contribute to develop a rational management and mitigation policy for the future use of the groundwater resources for drinking water supplies.
    Journal of Hydrology 06/2014; In press(Corrected Proof). DOI:10.1016/j.jhydrol.2014.05.055 · 3.05 Impact Factor
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    ABSTRACT: The mine tailings at Kombat, in semiarid northeastern Namibia, were investigated by the combination of solid-phase analyses, mineralogical methods, leaching tests, and speciation modeling. Dissolution of the most abundant primary sulfides, chalcopyrite and galena, released copper and lead which were adsorbed onto ferric oxyhydroxides or precipitated in the form of malachite, Cu2CO3(OH)2, and cerussite, PbCO3, respectively. Arsenic released from arsenopyrite was incorporated into ferric oxyhydroxides. Based on sequential extraction and (57)Fe Mössbauer spectroscopy, a large amount of ferric iron is present as low solubility hematite and goethite formed rapidly (<10 years) under warm semiarid climatic conditions, and arsenic in these phases is relatively tightly bound. It seems that Cu and especially Pb in carbonate minerals represent a more serious environmental risk. Immobilization of As in hematite has implications for other mining sites in regions with similar climatic conditions because this process results in long-term immobilization of As.
    Environmental Monitoring and Assessment 04/2014; 186(8). DOI:10.1007/s10661-014-3746-1 · 1.68 Impact Factor
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    ABSTRACT: Purpose Whereas mercury (Hg) has been extensively studied in gold mining areas (including artisanal mining), it is often overlooked as a minor contaminant in these districts, within which industrial base-metal mining and smelting are in operation. The aims of this study were to investigate Hg in tropical soils from mining and smelting areas in Namibia and Zambia and to apply statistical methods to generate models for the prediction of Hg concentrations in the soils studied. Materials and methods Twenty-one soil profiles (n = 159 soil samples) were collected in metal mining districts in the northern parts of Namibia (Tsumeb, Berg Aukas, Kombat) and in the Zambian Copperbelt (Kitwe, Mufulira). Total Hg was analysed by atomic absorption spectrometry and compared statistically with other physico-chemical and chemical soil parameters. Mercury concentrations in potential sources (feed and wastes from smelters as well as mine tailings, n = 35) were also determined. Results and discussion Mercury concentrations in soils from mining/smelting areas were significantly higher in northern Namibia (range 0.0038–4.39, mean 0.39, median 0.02 mg kg−1) than in the Zambian Copperbelt (range 0.0055–0.39, mean 0.02, median 0.01 mg kg−1). This phenomenon is related to the higher levels of Hg in the mine tailing materials as well as the feed/wastes from the smelters in Namibia (specifically in Berg Aukas and Tsumeb). Only 27 % (Namibia) and 26 % (Zambia) of the soil samples exceeded geochemical anomaly thresholds (0.033 and 0.016 mg kg−1, respectively), generally indicating a low Hg pollution level. The highest Hg concentrations were observed in the uppermost soil layers. Total Hg correlated significantly with other contaminants and, in the Zambian dataset, also with Corg and Stot. Conclusions Based on measurements of total Hg in soils from the mining/smelting areas in Namibia and Zambia, only one fourth of the samples exceeded geochemical anomaly thresholds, and they indicated a relatively low level of Hg pollution. Elevated Hg concentrations were only observed in topsoils in the immediate vicinities of mine tailings and active smelters. Constructed regression models were found to be useful for prediction of Hg concentrations at both of the regions studied.
    Journal of Soils and Sediments 03/2014; 15(3):648-658. DOI:10.1007/s11368-014-1035-9 · 2.11 Impact Factor
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    ABSTRACT: The concentrations of arsenic (As), copper (Cu), cobalt (Co), lead (Pb) and zinc (Zn) in washed leaves and washed and peeled tubers of cassava (Manihot esculenta Crantz, Euphorbiaceae) growing on uncontaminated and contaminated soils of the Zambian Copperbelt mining district have been analyzed. An enrichment index (EI) was used to distinguish between contaminated and uncontaminated areas. This index is based on the average ratio of the actual and median concentration of the given contaminants (As, Co, Cu, mercury (Hg), Pb and Zn) in topsoil. The concentrations of copper in cassava leaves growing on contaminated soils reach as much as 612 mg kg−1 Cu (total dry weight [dw]). Concentrations of copper in leaves of cassava growing on uncontaminated soils are much lower (up to 252 mg kg−1 Cu dw). The concentrations of Co (up to 78 mg kg−1 dw), As (up to 8 mg kg−1 dw) and Zn (up to 231 mg kg−1 dw) in leaves of cassava growing on contaminated soils are higher compared with uncontaminated areas, while the concentrations of lead do not differ significantly. The concentrations of analyzed chemical elements in the tubers of cassava are much lower than in its leaves with the exception of As.
    Journal of African Earth Sciences 03/2014; 99. DOI:10.1016/j.jafrearsci.2014.02.009 · 1.38 Impact Factor
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    ABSTRACT: A survey of groundwater from six geothermal springs in Namibia showed high concentrations of dissolved fluoride, with values up to 18.9 mg/l. All values are higher than both the WHO limit and the Namibian guideline. High concentrations of fluoride are linked to Na-HCO3 or Na-SO4-HCO3 groundwater types, with increasing sulphate and chloride concentrations towards the south of Namibia. Values of δ2H and δ18O are more negative for the north of the country, and with increasing altitude of springs and distance from precipitation sources towards the southeast from the Indian Ocean. A shift of about 1‰ from the LMWL for Windhoek was observed for δ18O samples, which was probably caused by the exchange with reservoir rocks. Values of δ34S(SO4) reflect mixing of two principal sulphate sources, i.e., dissolution of gypsum originating from playas and interaction with sulphidic mineralization in tectonic bedrock zones. Values of δ13C(DIC) seem to be affected by a variable vegetation cover and mainly by the input of endogenous CO2. Estimated reservoir temperatures vary from 60 °C to 126 °C, with a maximum value at the Ganigobes site. The geothermal springs of Namibia in this study do not meet drinking water standards and thus their water can be used only for other purposes e.g. for thermal spas. Treatment would be necessary to decrease dissolved fluorine concentrations for drinking water purposes.
    Journal of Geochemical Exploration 01/2014; 148. DOI:10.1016/j.gexplo.2014.08.012 · 2.43 Impact Factor
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    ABSTRACT: The abandoned Dubrava Mine, situated in the northern part of the Nizke Tatry Mts in the middle of Slovakia, was the most significant producer of antimony (Sb) in the former Czechoslovakia. Mine drainage from adits (containing up to 9,300 µg/L of Sb), mine waste dumps, and the leachate from mine tailings contribute Sb and arsenic (As) into nearby Paludzanka Creek and groundwater. Some drinking water resources have been closed due to excessive Sb concentrations; the concentration of Sb in one household well (126 µg/L) far exceeds the Sb drinking water limit of 5 µg/L. Although Sb is attenuated by dilution and adsorption on ferric iron in stream sediment in the Paludzanka Creek, Sb concentrations increase downstream of the mine tailings and then remain almost constant, leading to concentrations of 128 µg/L at the northern boundary of the study area. The dissolved As concentrations in the mine drainage are much lower than Sb, ranging from 4 to 62 µg/L. Flow and transport modeling confirmed the observed contamination pattern and the major role of the mine adits. Results of this study indicate serious Sb contamination, which could be mitigated by treatment of the adit discharges.
    Mine Water and the Environment 09/2013; 32(3):207-221. DOI:10.1007/s10230-013-0229-5 · 1.20 Impact Factor
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    ABSTRACT: Mining wastes of Zn-Pb ores were studied at Olkusz, Southern Poland, using X-ray diffraction, SEM/EDS analyses. Additionally the chemistry of surface water runoff collected on the tailings slope was analyzed. The surface layer of tailing piles contains pyrite and marcasite, and dolomite as predominant carbonate mineral. The principal secondary sulfate mineral is gypsum, but the presence of trace epsomite was also inferred. Grains of dolomite are relatively fresh: the source of Ca necessary for crystallization of gypsum seems to be highly corroded minor calcite. In surface runoff, pH is close to neutral; Ca and sulfate are the dominant ions, followed by Mg. Concentrations of sulfate reaches 939 mg/l, whereas concentrations of Ca and Mg are 389 mg/l and 15.43 mg/l, respectively. The principal heavy metal in runoff is Zn, reaching 2.65 mg/l. Most species in runoff exhibited a negative correlation with the amount of precipitation in 5 days preceding the formation of surface runoff, due to their presence in efflorescent salts precipitated in dry period. Bicarbonate showed a positive correlation with the amount of precipitation, probably due to enhanced dissolution of calcite under high water saturation conditions. The results of this study indicate a dominant role of the surface layer of tailings and previous precipitation conditions in the formation of the surface runoff chemistry. In the future, surface runoff and fast releases of contaminants may become more important as a consequence of on-going climatic changes resulting in higher intensity of storm events.
    Journal of Geochemical Exploration 09/2013; 132:54-62. DOI:10.1016/j.gexplo.2013.05.002 · 2.43 Impact Factor
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    ABSTRACT: Chemical weathering is one of the major geochemical processes that control the mobilization of heavy metals. The present study provides the first report on heavy metal fractionation in sediments (8-156 m) of Lake Titicaca (3,820 m a.s.l.), which is shared by the Republic of Peru and the Plurinational State of Bolivia. Both contents of total Cu, Fe, Ni, Co, Mn, Cd, Pb, and Zn and also the fractionation of these heavy metals associated with four different fractions have been determined following the BCR scheme. The principal component analysis suggests that Co, Ni, and Cd can be attributed to natural sources related to the mineralized geological formations. Moreover, the sources of Cu, Fe, and Mn are effluents and wastes generated from mining activities, while Pb and Zn also suggest that their common source is associated to mining activities. According to the Risk Assessment Code, there is a moderate to high risk related to Zn, Pb, Cd, Mn, Co, and Ni mobilization and/or remobilization from the bottom sediment to the water column. Furthermore, the Geoaccumulation Index and the Enrichment Factor reveal that Zn, Pb, and Cd are enriched in the sediments. The results suggest that the effluents from various traditional mining waste sites in both countries are the main source of heavy metal contamination in the sediments of Lake Titicaca.
    Environmental Monitoring and Assessment 08/2013; 185(12). DOI:10.1007/s10661-013-3306-0 · 1.68 Impact Factor
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    ABSTRACT: Environmental settings in the southern area of Lake Poopó in the Bolivian highlands, the Altiplano, have generated elevated amounts of arsenic (As) in the water. The area is characterised by a semiarid climate, slow hydrological flow and geologic formations of predominantly volcanic origin. The present study aimed at mapping the extent of the water contamination in the area and to investigate the geogenic sources and processes involved in the release of As to the groundwater. Ground- and surface-water samples were collected from 24 different sites, including drinking water wells and rivers, in the southern Poopó basin in two different field campaigns during the dry and rainy seasons. The results revealed variable levels of As in shallow drinking water wells and average concentration exceeding the WHO guidelines value. Arsenic concentrations range from below 5.2μg/L (the detection level) to 207μg/L and averages 72μg/L. Additionally, high boron (B) concentrations (average 1902μg/L), and high salinity are further serious concerns for deteriorating the groundwater quality and rendering it unsuitable for drinking. Groundwater is predominantly of the Na-Cl-HCO3 type or the Ca-Na-HCO3 type with neutral or slightly alkaline pH and oxidising character. While farmers are seriously concerned about the water scarcity, and on a few occasions about salinity, there are no concerns about As and B present at levels exceeding the WHO guidelines, and causing negative long term effects on human health. Sediment samples from two soil profiles and a river bed along with fourteen rock samples were also collected and analysed. Sequential extractions of the sediments together with the calculation of the mineral saturation indices indicate that iron oxides and hydroxides are the important secondary minerals phases which are important adsorbents for As. High pH values, and the competition of As with HCO3 and dissolved silica for the adsorption sites probably seems to be an important process for the mobilisation of As in the shallow groundwaters of the region. Continuous monitoring and expansion of monitoring systems are necessary prerequisites for better understanding of the pattern of As mobilisation in the Southern Poopó Basin.
    Journal of hazardous materials 07/2013; 262. DOI:10.1016/j.jhazmat.2013.06.078 · 4.33 Impact Factor

Publication Stats

1k Citations
152.58 Total Impact Points

Institutions

  • 2009–2015
    • Palacký University of Olomouc
      • • Faculty of Science
      • • Department of Geology
      Olmütz, Olomoucký, Czech Republic
  • 2002–2012
    • Charles University in Prague
      • Institute of Hydrogeology, Engineering Geology and Applied Geophysics
      Praha, Praha, Czech Republic
  • 2004–2009
    • Masaryk University
      • Faculty of Science
      Brünn, South Moravian, Czech Republic
    • Laval University
      • Department of Geology and Geological Engineering
      Québec, Quebec, Canada