80 research outputs found

    Baseline to Evaluate Off-Site Suspended Sediment-Related Mining Effects in the Alto Tajo Natural Park, Spain

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    Mining is a human activity with considerable environmental impact. To evaluate such impacts, international laws require undertaking local studies based on direct sampling to establish baseline conditions of parameters modified by human activities. Mining takes place near the Alto Tajo Natural Park, where a suspended sediment concentration (SSC) baseline is required to determine whether mining affects water quality. To this end, we have monitored the Tajo River and its tributary the Tajuelo following Before–After Control-Impact (BACI) techniques, recommended by Australian and New Zealand laws, requiring a specific method based on continuous monitoring and sampling to enable evaluation of SSCs. An SSC baseline has been defined at stations situated upstream of the mining area and compared with those downstream. The highest detected SSC upstream of the Tajuelo mines was 24 g l−1 whereas the highest simultaneous downstream value was 391 g l−1, more than one order of magnitude higher than the supposed baseline (24 g l−1). Additionally, this value is 1000 times more than the average concentration of 25 mg l−1, used by the European Union until 2015, to guarantee the quality of salmonid waters. Following a BACI approach, a statistically significant SSC impact has been identified. The mined areas are the only source that can explain this increase. This is the first instance that such an increase and baseline have been found using this method. BACI is a simple and reliable method recommended for studying degraded areas rather than an irrelevant, fixed standard as included in most international laws. Copyright © 2016 John Wiley & Sons, Ltd.This study was funded by: (i) Research Project CGL2010-21754-C02-01 (Spanish Ministry of Science and Technology, and Ministry of Economy); (ii) the Department of Agriculture and Environment of Castile—La Mancha through its socalled “Fondos Verdes” (Green Funding); (iii) the research contract 249/2015 between CAOBAR and UCM; (iv) the Ecological Restoration Network REMEDINAL-3 of the Madrid Community (S2013/MAE-2719); (v) the Spanish National Research Council (CSIC) for Ph.D. Grant JAEPredoc to IZAPeer reviewe

    Effects of Topography and Surface Soil Cover on Erosion for Mining Reclamation: The Experimental Spoil Heap at El Machorro Mine (Central Spain)

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    Mining reclamation tries to reduce environmental impacts, including accelerated runoff, erosion and sediment load in the nearby fluvial networks and their ecosystems. This study compares the effects of topography and surface soil cover on erosion on man-made slopes coming from surface mining reclamation in Central Spain. Two topographic profiles, linear and concave, with two surface soil covers, subsoil and topsoil, were monitored for two hydrologic years. Sediment load, rill development and plant colonization from the four profiles were measured under field conditions. The results show that, in the case of this experiment, a thick and non-compacted topsoil cover on a linear slope yielded less sediment than carbonate colluvium or topsoil cover on a concave slope. This study also shows that vegetation establishment, which plays an important role in erosion control, depends on topography. Plant cover was more widespread and more homogeneous on linear profiles with topsoil cover. On concave slopes, plant establishment was severely limited on the steepest upper part and favoured in the bottom. This study suggests that management of topography and surface soil cover should be approached systematically, taking three outcomes into consideration: (i) topsoil can lead to a successful mining reclamation regardless of topography, (ii) created concave slopes can lead to a successful mining reclamation and (iii) topography determines the vegetation colonization pattern.The experiment was funded by a research contract between the Spanish mining company 602 CAOBAR S.A. and the Department of Geodynamics of the Complutense University of Madrid 603 (research contract numbers 234/2007, 290/2008 261/2009). The data analyses and manuscript 604 production were developed within two Research Projects, CGL2009-14508-C02-01 and 605 CGL2010-21754-C02, of the Spanish Ministry of Science and Technology and by the 606 Ecological Restoration network REMEDINAL-2 (S2009/AMB-1783).Peer reviewe

    A descriptive and quantitative approach regarding erosion and development of landforms on abandoned mine tailings: New insights and environmental implications from SE Spain

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    The San Cristóbal–Perules mining site in Mazarrón in southeast Spain was subjected to about a hundred years of intense mining activity for lead, silver, and zinc. Metallurgical operations (smelting, calcination, gravity concentration) carried out during the late nineteenth century–early twentieth century induced significant land transformation, and the most conspicuous wastes of this period consist of a chaotic piling of ‘old’ tailing deposits. Later on, during the mid-twentieth century, ‘modern’ tailings resulting from froth flotation were accumulated filling small valleys; these latter valley-fill tailings rose sequentially according to the upstream construction method, progressively raising the level of the dam during the process. Once abandoned, both types of tailing deposits underwent severe erosion, resulting in a mosaic of erosional and sedimentary landforms developed upon (e.g., gully formation) and within them (e.g., piping). We made an inventory and classification of these landforms. Our study shows the geomorphic work to reestablish a new steady state between the tailings deposits and the local erosive conditions. This scenario implies several hazards related to the extremely high heavy metal contents of these tailings and the geomorphic instability of the deposits. We also quantified the tailings tonnage and erosion that occurred at one of the tailings dams (El Roble). As shown by an oblique aerial photograph taken in 1968, this dam had a terraced topography, whereas in 2013 this morphology had evolved into a badland-type relief with deep parallel gullies. By recognizing and surveying specific, remnant points along the benches and outslopes of the older terraced topography, we were able to build up a first digital elevation model (DEM1) reflecting the initial topography. A second DEM, this time showing the present topography, allowed quantification of erosion via Material Loss = DEM1 − DEM2. This yields an erosion rate (1968–2009) of 151.8 Mg (MT) ha− 1 y− 1, which matches well typical values for erosion of mined areas, commonly above 100 Mg (MT) ha− 1 y− 1. Abandoned mine tailing deposits are extremely common in the semiarid scenarios of the SW USA, Australia, Chile, and Peru. Given the similarities of these scenarios with SE Spain, the example from Mazarrón may provide useful new insights regarding the erosion and geomorphic evolution of such tailing deposits. These matters should be addressed in key environmental actions such as mine closure plans and land reclamation projects. A solution may come via restoration of these deposits through landform design involving the building up of stable mature landscapes, which in turn can withstand erosion much more easily.Peer reviewe

    Incidence, clinical characteristics and management of inflammatory bowel disease in Spain: large-scale epidemiological study

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    (1) Aims: To assess the incidence of inflammatory bowel disease (IBD) in Spain, to describe the main epidemiological and clinical characteristics at diagnosis and the evolution of the disease, and to explore the use of drug treatments. (2) Methods: Prospective, population-based nationwide registry. Adult patients diagnosed with IBD—Crohn’s disease (CD), ulcerative colitis (UC) or IBD unclassified (IBD-U)—during 2017 in Spain were included and were followed-up for 1 year. (3) Results: We identified 3611 incident cases of IBD diagnosed during 2017 in 108 hospitals covering over 22 million inhabitants. The overall incidence (cases/100, 000 person-years) was 16 for IBD, 7.5 for CD, 8 for UC, and 0.5 for IBD-U; 53% of patients were male and median age was 43 years (interquartile range = 31–56 years). During a median 12-month follow-up, 34% of patients were treated with systemic steroids, 25% with immunomodulators, 15% with biologics and 5.6% underwent surgery. The percentage of patients under these treatments was significantly higher in CD than UC and IBD-U. Use of systemic steroids and biologics was significantly higher in hospitals with high resources. In total, 28% of patients were hospitalized (35% CD and 22% UC patients, p < 0.01). (4) Conclusion: The incidence of IBD in Spain is rather high and similar to that reported in Northern Europe. IBD patients require substantial therapeutic resources, which are greater in CD and in hospitals with high resources, and much higher than previously reported. One third of patients are hospitalized in the first year after diagnosis and a relevant proportion undergo surgery. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    The CARMENES search for exoplanets around M dwarfs

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    Context. The CARMENES instrument, installed at the 3.5 m telescope of the Calar Alto Observatory in AlmerĂ­a, Spain, was conceived to deliver high-accuracy radial velocity (RV) measurements with long-term stability to search for temperate rocky planets around a sample of nearby cool stars. Moreover, the broad wavelength coverage was designed to provide a range of stellar activity indicators to assess the nature of potential RV signals and to provide valuable spectral information to help characterise the stellar targets. Aims: We describe the CARMENES guaranteed time observations (GTO), spanning from 2016 to 2020, during which 19 633 spectra for a sample of 362 targets were collected. We present the CARMENES Data Release 1 (DR1), which makes public all observations obtained during the GTO of the CARMENES survey. Methods: The CARMENES survey target selection was aimed at minimising biases, and about 70% of all known M dwarfs within 10 pc and accessible from Calar Alto were included. The data were pipeline-processed, and high-level data products, including 18 642 precise RVs for 345 targets, were derived. Time series data of spectroscopic activity indicators were also obtained. Results: We discuss the characteristics of the CARMENES data, the statistical properties of the stellar sample, and the spectroscopic measurements. We show examples of the use of CARMENES data and provide a contextual view of the exoplanet population revealed by the survey, including 33 new planets, 17 re-analysed planets, and 26 confirmed planets from transiting candidate follow-up. A subsample of 238 targets was used to derive updated planet occurrence rates, yielding an overall average of 1.44 ± 0.20 planets with 1 M⊕ &lt; Mpl sin i &lt; 1000 M⊕ and 1 day &lt; Porb &lt; 1000 days per star, and indicating that nearly every M dwarf hosts at least one planet. All the DR1 raw data, pipeline-processed data, and high-level data products are publicly available online. Conclusions: CARMENES data have proven very useful for identifying and measuring planetary companions. They are also suitable for a variety of additional applications, such as the determination of stellar fundamental and atmospheric properties, the characterisation of stellar activity, and the study of exoplanet atmospheres

    Data Descriptor : A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins

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    Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The European Multi Lake Survey (EMLS) in summer 2015 was an initiative among scientists from 27 countries to collect and analyse lake physical, chemical and biological variables in a fully standardized manner. This database includes in-situ lake variables along with nutrient, pigment and cyanotoxin data of 369 lakes in Europe, which were centrally analysed in dedicated laboratories. Publishing the EMLS methods and dataset might inspire similar initiatives to study across large geographic areas that will contribute to better understanding lake responses in a changing environment.Peer reviewe

    A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins

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    Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

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    This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic
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