[Show abstract][Hide abstract] ABSTRACT: Gamma dose equivalent (0.18 ìSv/h) is higher than background of Salamanca province, Guarda district and worldwide average.
The concentration of water-soluble U (or bioavailable) in soils regionally distributed with no influence of mining works, ranges from 1 to 137 μg/L with a median of 9 μg/l.
The U content in shallow well waters ranges 0.1 – 79.5 μg/L with a median of 0.4 μg/l. In river and stream samples the concentration are lower (median < 0.1 μg/L). The association of U, As and pH in water samples indicates an increase of U and As solubility with increasing pH linked to the formation of uranyl-carbonate and uranyl-arsenate complexes.
[Show abstract][Hide abstract] ABSTRACT: High concentrations of arsenic (As) in groundwater of the Duero River Basin have created a public health concern in some provinces of Spain. However, the mechanism of As mobilization and influence of surface water–groundwater interaction, nutrients and different geochemical reactions on As removal have not yet been clearly reported. Therefore, this study investigated the possible mechanisms of As release, and temporal variations of As with respect to nitrate content in groundwater. Hydrogeochemical characteristics of groundwater sampled along three years in a region of central Spain showed high As contents exceeding EU guideline value of 10 μg/l. Significant positive correlations were found between As and bicarbonate concentrations in water samples. These results suggest a possible mechanism of As mobilization from sediments to groundwater as follows: bicarbonate ions can displace HAsO42- adsorbed on surface of aquifer Fe oxyhydroxide, other minerals and sediments. In addition, the high pH values of the groundwater might also favor the As desorption processes. The results showed that As concentrations in water samples decreased along with the increase in nitrate concentrations across the whole period of study (2001, 2003 and 2007). The negative and significant correlations between As and nitrate contents in water reflect the temporal variation of As concentration due to the effect of surface water–groundwater interaction and nutrient input into groundwater. The increased use of nitrogen fertilizers and pig manure in agriculture practices increased the nitrate content in groundwater during the period of this study, which could have favored the precipitation of Fe oxyhydroxides and As adsorption.
No preview · Article · Dec 2013 · Physics and Chemistry of the Earth Parts A/B/C
[Show abstract][Hide abstract] ABSTRACT: In the presented study the airborne fungal spores of the semiarid city of Cartagena, Spain, are identified and quantified by means of viable or non-viable sampling methods. Airborne fungal samples were collected simultaneously using a filtration method and a pollen and particle sampler based on the Hirst methodology. This information is very useful for elucidating geographical patterns of hay fever and asthma. The qualitative results showed that when the non-viable methodology was employed, Cladosporium, Ustilago, and Alternaria were the most abundant spores identified in the atmosphere of Cartagena, while the viable methodology showed that the most abundant taxa were: Cladosporium, Penicillium, Aspergillus and Alternaria. The quantitative results of airborne fungal spores identified by the Hirst-type air sampler (non-viable method), showed that Deuteromycetes represented 74% of total annual spore counts, Cladosporium being the major component of the fungal spectrum (62.2%), followed by Alternaria (5.3%), and Stemphylium (1.3%). The Basidiomycetes group represented 18.9% of total annual spore counts, Ustilago (7.1%) being the most representative taxon of this group and the second most abundant spore type. Ascomycetes accounted for 6.9%, Nectria (2.3%) being the principal taxon. Oomycetes (0.2%) and Zygomycestes and Myxomycestes (0.06%) were scarce. The prevailing species define our bioaerosol as typical of dry air. The viable methodology was better at identifying small hyaline spores and allowed for the discrimination of the genus of some spore types. However, non-viable methods revealed the richness of fungal types present in the bioaerosol. Thus, the use of both methodologies provides a more comprehensive characterization of the spore profile.
No preview · Article · Dec 2013 · Annals of agricultural and environmental medicine: AAEM
[Show abstract][Hide abstract] ABSTRACT: Extreme environments may support communities of microalgae living at the limits of their tolerance. It is usually assumed that these extreme environments are inhabited by extremophile species. However, global anthropogenic environmental changes are generating new extreme environments, such as mining-effluent pools of residual waters from uranium mining with high U levels, acidity and radioactivity in Salamanca (Spain). Certain microalgal species have rapidly adapted to these extreme waters (uranium mining in this area began in 1960). Experiments have demonstrated that physiological acclimatisation would be unable to achieve adaptation. In contrast, rapid genetic adaptation was observed in waters ostensibly lethal to microalgae by means of rare spontaneous mutations that occurred prior to the exposure to effluent waters from uranium mining. However, adaptation to the most extreme conditions was only possible after recombination through sexual mating because adaptation requires more than one mutation. Microalgae living in extreme environments could be the descendants of pre-selective mutants that confer significant adaptive value to extreme contamination. These "lucky mutants" could allow for the evolutionary rescue of populations faced with rapid environmental change.
No preview · Article · Oct 2013 · Aquatic toxicology (Amsterdam, Netherlands)
[Show abstract][Hide abstract] ABSTRACT: An area affected by the long-term weathering of sphalerite-bearing mine wastes was studied in order to assess the environmental fate and behaviour of different toxic elements occurring in this mineral. Soil and plant samples were collected at different distances from the polluting sources and analysed for the content and distribution of Zn, Cd and Tl. Soils are highly polluted with Zn and Cd, reaching total concentrations up to 92,940 and 218 mg kg− 1, respectively. Soil contamination with Tl appears slight, with maximum total concentrations of 1.13 mg kg− 1. Mobile contents of Zn and Cd also reach high values, above 500 and 5 mg kg− 1, respectively. There is a great risk of an additional mobilization of Zn and Cd under acidic oxidizing conditions, whereas Tl mostly occurs in the residual fraction. Of the plants growing in this area, Jasione montana L. and Orchis maculata L. show a high risk of Cd incorporation in the trophic chain. These plants accumulate Cd concentrations up to 12.6 and 4.50 mg kg− 1 in their aerial parts.
[Show abstract][Hide abstract] ABSTRACT: A mining area affected by the abandoned mine exploitation of a stibnite deposit was studied to establish the current and eventual environmental risks and to propose possible remediation practices. Soil and plant samples were collected at different places in this area and analyzed for their Sb content and distribution. Critical soil total concentrations of Sb were found, with values ranging from 585 to 3184mgkg(-1) dry weight in the uppermost soil layer, and decreasing progressively with soil depth. The readily labile Sb contents represent <2% of the total concentrations, whereas the soil Sb contents more susceptible of being mobilized under changing environmental conditions attain values of about 4-9% of the total concentrations. Remediation measures should be undertaken to limit off-site migration of Sb. Within the tolerant plant community growing in this area, the shrub Daphne gnidium L. stands out for its relatively high root Sb accumulation and low Sb translocation, suggesting its feasibility to be used in Sb phytostabilization strategies.
No preview · Article · Feb 2013 · Science of The Total Environment
[Show abstract][Hide abstract] ABSTRACT: Soil pollution with antimony is of increasing environmental concern worldwide. Measures for its control and to attenuate the risks posed to the ecosystem are required. In this study the application of several iron and aluminium oxides and oxyhydroxides as soil amendments was evaluated in order to assess their feasibility to stabilize Sb in mining polluted soils. Mine soils with different pollution levels were amended with either goethite, ferrihydrite or amorphous Al oxide at various ratios (0-10%). The effectiveness of such treatments was assessed by both batch and column leaching tests. The use of ferrihydrite or amorphous Al oxide proved to be highly effective to stabilize Sb. Immobilization levels of 100% were found when doses of 5% ferrihydrite or 10% amorphous Al oxide were applied, regardless of the soil Sb load. Column leaching studies also showed a high Sb leaching reduction (>75%) when soils were amended with 1% ferrihydrite or 5% amorphous Al oxide. Moreover, such treatments proved to simultaneously immobilize As and Pb in a great extent when soils were also polluted with such toxic elements.
[Show abstract][Hide abstract] ABSTRACT: An agricultural area impacted by the former exploitation of an arsenical lead-antimony deposit was studied in order to assess the current and eventual environmental and health impacts. Samples of soils and cultivated (wheat) and spontaneously growing plants were collected at different distances from the mine pits and analyzed for the toxic element content and distribution. The soil total concentrations of Sb, As and Pb found in the uppermost soil layer (14.1-324, 246-758 and 757-10,660mgkg(-1), respectively) greatly surpass their maximum tolerable levels in agricultural soils. Wheat grain Pb concentrations (0.068-1.36mgkg(-1)) exceed the prescribed health standard, whereas Sb (<0.05-0.103mgkg(-1)) and As (<0.05-0.126mgkg(-1)) concentrations are below the permissible limits fixed for cereals. Of the spontaneously growing plants, Dactylis glomerata L. shows a relatively high root Pb accumulation and a very low Pb translocation, suggesting its feasibility to be used in Pb phytostabilization strategies.
No preview · Article · Oct 2012 · Science of The Total Environment
[Show abstract][Hide abstract] ABSTRACT: Weak pressure gradient over the Iberian Peninsula and African dust outbreaks is discussed. African dust in the southeast Iberian Peninsula was detected at surface levels in southeastern Iberia during 562 of 1,613 days between January 2004 and May 2008. On October 7, 2006, the Iberian plateau was affected by a high over the Bay of Biscay at mean sea level pressure. On October 9, 2006, the system of high pressure at mean sea level continued over Central Europe, with scarce influence over Spain. The highest air masses remain within a radius of around 800 km during the five days, when substantial levels of African dust are detected. by examining the levels of particulate matter (PM) every day and the models of the origin and trajectory of the air masses, it can be concluded that synoptic patterns without strong systems can be responsible for peaks in atmospheric pollution across parts of Iberia.
Preview · Article · Aug 2012 · Bulletin of the American Meteorological Society
[Show abstract][Hide abstract] ABSTRACT: The main objective of this study was to determine arsenic (As) levels in vegetables collected from the markets of Dhaka, Bangladesh and for comparison from Salamanca, Spain by HGAAS under optimal conditions, and the potential health risk from consumption of these vegetables. The mean and range of the total As concentration in the vegetables from the markets of Dhaka, Bangladesh were 114 and 1.0-293 μg/kg, respectively. Total As concentration in 77% of Bangladesh vegetables measured was higher than that recommended by the standard. The mean and range of As concentrations for vegetables grown in Spain were 65 and bdl-130 μg/kg, respectively, for Salamanca, 102 and bdl-423 μg/kg, respectively, for Almeria. The As content of the Bangladesh vegetables was approximately twofold to threefold higher than those observed for the vegetables from Almeria and Salamanca (Spain), but in some cases, were similar or less. Daily consumption of As-rich vegetables may result in an additional source of As in the diet, based on the provisional tolerable intake of As for adults recommended by WHO.
No preview · Article · Jun 2012 · Bulletin of Environmental Contamination and Toxicology
[Show abstract][Hide abstract] ABSTRACT: It has been hypothesized that exposure to heavy metals may impair male reproduction. To measure the effect produced by low doses of heavy metals on semen parameters, it is necessary to clarify in which body fluids those measurements must be performed. Sixty-one men attending infertility clinics participated in our study. Concentrations of lead, cadmium, and mercury were measured in whole blood, blood plasma, and seminal plasma using spectroanalytical and electrochemical methods. Semen analyses were performed according to World Health Organization criteria. For statistical analysis, Spearman's rank correlations, mean comparison tests, and discriminant analysis were calculated. Significant correlations between the measured concentrations of the three heavy metals in the same biological fluids were observed. However, no similar relationship was seen when comparing the concentrations in different body fluids of the same metal. According to our results and previous publications, seminal plasma might be the best body fluid for assessing impairment of human semen parameters.
Full-text · Article · Jan 2012 · Advances in Urology
[Show abstract][Hide abstract] ABSTRACT: The mobility and phytoavailability of arsenic in an area affected by the abandoned exploitation of an arsenical tungsten–tin deposit was studied to establish the current and eventual environmental risks and to propose possible remediation practices. Soil and plant samples were collected at different distances from the polluting sources and analyzed for their As content and distribution. Critical soil total concentrations of As were found, with values in the range 175–2300mgkg−1. The readily labile As contents represent
[Show abstract][Hide abstract] ABSTRACT: The drying process of fresh plant materials may affect the porous structure, dehydration and a number of quality characteristics
of these materials. Therefore, this study has investigated the effect of different drying processes on the variation of metal
and metalloid concentrations in the dried plant materials. Seven varieties of native plant species collected from São Domingos
mine were analyzed by instrumental neutron activation analysis (INAA) to investigate the effects of freeze-drying (FD), ambient
air-drying (AAD) and oven-drying (OD) process on the concentrations of metals and metalloids in the plant biomass. Comparison
of ambient air-dried, oven-dried and freeze-dried preparations allows a phenomenological description of the dehydration artefacts.
In the quantitative analysis of metals and metalloids, FD and OD plant samples show the higher concentrations of metals and
metalloids when compared to those in the AAD plant biomass. The freeze-drying process is comparatively reliable for determination
of metals and metalloids concentrations in plant materials.
KeywordsNeutron activation analysis–Drying processes–Plant biomass–Metals and metalloids concentration–Dehydration
Full-text · Article · Jul 2011 · Journal of Radioanalytical and Nuclear Chemistry
[Show abstract][Hide abstract] ABSTRACT: We studied the bacterial diversity at a single location (the Terrubias mine; Salamanca province, Spain) with a gradient of soil As contamination to test if increasing levels of As would (1) change the preponderant groups of arsenic-resistant bacteria and (2) increase the tolerance thresholds to arsenite [As(III)] and arsenate [As(V)] of such bacteria. We studied the genetic and taxonomic diversity of culturable arsenic-resistant bacteria by PCR fingerprinting techniques and 16S rRNA gene sequencing. Then, the tolerance thresholds to As(III) and As(V) were determined for representative strains and mathematically analyzed to determine relationships between tolerances to As(III) and As(V), as well as these tolerances with the soil contamination level. The diversity of the bacterial community was, as expected, inversely related to the soil As content. The overall preponderant arsenic-resistant bacteria were Firmicutes (mainly Bacillus spp.) followed by γ-Proteobacteria (mainly Pseudomonas spp.), with increasing relative frequencies of the former as the soil arsenic concentration increased. Moreover, a strain of the species Rahnella aquatilis (γ-Proteobacteria class) exhibited strong endurance to arsenic, being described for the first time in literature such a phenotype within this bacterial species. Tolerances of the isolates to As(III) and As(V) were correlated but not with their origin (soil contamination level). Most of the strains (64%) showed relatively low tolerances to As(III) and As(V), but the second most numerous group of isolates (19%) showed increased tolerance to As(III) rather than to As(V), even though the As(V) anion is the prevalent arsenic species in soil solution at this location. To our knowledge, this is the first study to report a shift towards preponderance of Gram-positive bacteria (Firmicutes) related to high concentrations of soil arsenic. It was also shown that, under aerobic conditions, strains with relatively enhanced tolerance to As(III) predominated over the most As(V)-tolerant ones.
[Show abstract][Hide abstract] ABSTRACT: A mining area affected by the abandoned exploitation of an arsenical tungsten deposit was studied in order to assess its arsenic pollution level and the feasibility of native plants for being used in phytoremediation approaches. Soil and plant samples were collected at different distances from the polluting sources and analysed for their As content and distribution. Critical soil total concentrations of As were found, with values in the range 70-5330 mg kg(-1) in the uppermost layer. The plant community develops As tolerance by exclusion strategies. Of the plant species growing in the most polluted site, the shrubs Salix atrocinerea Brot. and Genista scorpius (L.) DC. exhibit the lowest bioaccumulation factor (BF) values for their aerial parts, suggesting their suitability to be used with revegetation purposes. The species Scirpus holoschoenus L. highlights for its important potential to stabilise As at root level, accumulating As contents up to 3164 mg kg(-1).
No preview · Article · Jun 2011 · Environmental Pollution
[Show abstract][Hide abstract] ABSTRACT: An extensive and remote gold mining region located in the East of Venezuela has been studied with the aim of assessing the distribution and mobility of mercury in soil and the level of Hg pollution at artisanal gold mining sites. To do so, soils and pond sediments were sampled at sites not subject to anthropological influence, as well as in areas affected by gold mining activities. Total Hg in regionally distributed soils ranged between 0.02 mg kg(-1) and 0.40 mg kg(-1), with a median value of 0.11 mg kg(-1), which is slightly higher than soil Hg worldwide, possibly indicating long-term atmospheric input or more recent local atmospheric input, in addition to minor lithogenic sources. A reference Hg concentration of 0.33 mg kg(-1) is proposed for the detection of mining affected soils in this region. Critical total Hg concentrations were found in the surrounding soils of pollutant sources, such as milling-amalgamation sites, where soil Hg contents ranged from 0.16 mg kg(-1) to 542 mg kg(-1) with an average of 26.89 mg kg(-1), which also showed high levels of elemental Hg, but quite low soluble+exchangeable Hg fraction (0.02-4.90 mg kg(-1)), suggesting low Hg soil mobility and bioavailability, as confirmed by soil column leaching tests. The vertical distribution of Hg through the soil profiles, as well as variations in soil Hg contents with distance from the pollution source, and Hg in pond mining sediments were also analysed.
No preview · Article · Apr 2011 · Journal of Environmental Management
[Show abstract][Hide abstract] ABSTRACT: Arsenopyrite-rich wastes from abandoned tungsten and tin exploitations were studied to determine the composition and characteristics of the secondary phases formed under natural weathering conditions so as to assess their potential environmental risk. Representative weathered arsenopyrite-bearing rock wastes collected from the mine dumps were analysed using the following techniques: X-ray powder diffraction (XRD) analysis, polarizing microscopy analysis, electron microprobe analysis (EMPA) and microRaman and Mössbauer spectroscopies. Scorodite, pharmacosiderite and amorphous ferric arsenates (AFA) with Fe/As molar ratios in the range 1.2-2.5 were identified as secondary arsenic products. The former showed to be the most abundant and present in the different studied mining areas. Its chemical composition showed to vary in function of the original surrounding rock mineralogy in such a way that phosphoscorodite was found as the mineral variety present in apatite-containing geoenvirons. Other ever-present weathering phases were goethite and hydrous ferric oxides (HFO), displaying, respectively, As retained amounts about 1 and 20% (expressed as As(2)O(5)). The low solubility of scorodite, the relatively low content of AFA and the formation of compounds of variable charge, mostly of amorphous nature, with high capacity to adsorb As attenuate importantly the dispersion of this element into the environment from these arsenopyrite-bearing wastes.
Full-text · Article · Feb 2011 · Journal of hazardous materials
[Show abstract][Hide abstract] ABSTRACT: Animal studies have shown the reproductive toxicity of a number of heavy metals. Very few human observational studies have analyzed the relationship between male reproductive function and heavy metal concentrations in diverse biological fluids.
The current study assessed the associations between seminal and hormonal parameters and the concentration of the 3 most frequent heavy metal toxicants (lead, cadmium and mercury) in three different body fluids. Sixty one men attending infertility clinics that participated in a case-control study to explore the role of environmental toxins and lifestyles on male infertility were analyzed. Concentration of lead, cadmium and mercury were measured in blood and seminal plasma and whole blood using anodic stripping voltammetry and atomic absorption spectrophotometry. Serum samples were analyzed for follicle-stimulating hormone, luteinizing hormone and testosterone. Semen analyses were performed according to World Health Organization criteria. Mann-Whitney test and Spearman's rank correlations were used for unadjusted analyses. Multiple linear regression models were performed controlling for age, body mass index and number of cigarettes per day.
There were no significant differences between cases and controls in the concentrations of heavy metals in any of the three body fluids. In multivariate analyses using all subjects no significant associations were found between serum hormone levels and metal concentrations. However there was a significant positive association between the percentage of immotile sperms and seminal plasma levels of lead and cadmium.
Our results suggest that the presence of lead and cadmium in the reproductive tract of men may be related to a moderate alteration of their seminal parameters.
Full-text · Article · Jan 2011 · Environmental Health
[Show abstract][Hide abstract] ABSTRACT: High levels of total and bioavailable As in soils in mining areas may lead to the potential contamination of surface water and groundwater, being toxic to human, plants, and animals. The soils in the studied area (Province of Salamanca, Spain) recorded a total As concentration that varied from 5.5mg/kg to 150mg/kg, and water-soluble As ranged from 0.004mg/kg to 0.107mg/kg, often exceeding the guideline limits for agricultural soil (50mg/kg total As, 0.04mg/kg water-soluble As). The range of As concentration in pond water was <0.001microg/l-60microg/l, with 40% of samples exceeding the maximum permissible level (10microg/l) for drinking water. Estimated bioavailable As in soil varied from 0.045mg/kg to 0.760mg/kg, around six times higher than water-soluble As fraction, which may pose a high potential risk in regard to its entry into food chain. Soil column leaching tests show an As potential mobility constant threatening water contamination by continuous leaching. The vertical distribution of As through soil profiles suggests a deposition mechanism of this element on the top-soils that involves the wind or water transport of mine tailings. A similar vertical distribution of As and organic matter (OM) contents in soil profiles, as well as, significant correlations between As concentrations and OM and N contents, suggests that type and content of soil OM are major factors for determining the content, distribution, and mobilization of As in the soil. Due to the low supergenic mobility of this element in mining environments, the soil pollution degree in the studied area is moderate, in spite of the elevated As contents in mine tailings.
No preview · Article · Sep 2010 · Science of The Total Environment
[Show abstract][Hide abstract] ABSTRACT: Natural soils without apparent human influence were selected to determine the background concentration of Cd, Cu, Pb, Zn, Cr, and Ni. Reference concentrations of soil heavy metals are necessary for assessing the degree of metal pollution affected by anthropogenic activities and inputs. Samples of uncultivated (i.e., native) soils were collected from central-western Spain. For each element studied, the anomaly thresholds, ‘upper whisker,’ and baseline concentrations were calculated. For each main soil group—Luvisols (Alfisols), Cambisols (Inceptisols) and Leptosols/Regosols (Entisols)—the mean contents and baseline concentrations were also reported. Results of these analyses indicated total soil contents were within the normal global range. Geometric mean contents (mg kg−1) were: Cd, 0.21; Cr, 20.4; Cu, 14.4; Ni, 25.7; Pb, 34.7; and Zn, 42.6. A study on the metal cation available contents (extraction with 1 M ammonium acetate) was also conducted, since total contents in affected soils are only indicative of the pollution degree but not of the real risks involved. Risks of pollution of waters and to human health through food chain transfer are determined by the mobility and availability of elements. Relationships between element concentration and some pedological parameters were also determined, as well as element translocation through the soil profile, and the relationship between available to bound (i.e., free Fe oxyhydroxide fractions) forms. A factorial analysis was performed to determine which factors govern soil metal distribution. Soil forming factor that mainly determined the total contents in soils was the nature of the parent rock. Thus, chalcophile elements, Cu, Zn, Cd, and Pb, were more abundant in soils developed from slates of the palaeozoic basement, which contain abundant pyrite, while siderophile elements, Cr and Ni, were more abundant in soils derived from Fe-rich materials, such as clay-rich Tertiary sediments.
No preview · Article · Aug 2010 · Arid Land Research and Management