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El desafío de la seguridad hídrica en España en un contexto de adaptación al cambio climático
No full textOverexpression of the Efflux Pumps SmeVWX and SmeDEF Is a Major Cause of Resistance to Co-trimoxazole in Stenotrophomonas maltophilia
No full textCo-trimoxazole is one of the antimicrobials of choice for treating Stenotrophomonas maltophilia infections. Most works on the molecular epidemiology of the resistance to this drug combination are based on the analysis of sul genes. Nevertheless, the existence of clinical co-trimoxazole-resistant S. maltophilia isolates that do not harbor sul genes has been reported. To investigate potential mutations that can reduce the susceptibility of S. maltophilia to co-trimoxazole, spontaneous S. maltophilia co-trimoxazole-resistant mutants isolated under different co-trimoxazole concentrations were studied. All mutants presented phenotypes compatible with the overexpression of either SmeVWX (94.6%) or SmeDEF (5.4%). Indeed, the analysis of a selected set of strains showed that the overexpression of either of these efflux pumps, which was due to mutations in their regulators smeRv and smeT, respectively, was the cause of co-trimoxazole resistance. No other efflux pump was overexpressed in any of the studied mutants, indicating that they do not participate in the observed resistance phenotype. The analysis of mutants overexpressing or lacking SmeDEF or SmeVWX shows that SmeDEF contributes to the intrinsic and acquired resistance to co-trimoxazole in S. maltophilia, whereas SmeVWX only contributes to acquired resistance. It is important to highlight that all mutants were less susceptible to other antibiotics, including chloramphenicol and quinolones. Since both SmeVWX and SmeDEF are major determinants of quinolone resistance, the potential cross-selection of resistance to co-trimoxazole and quinolones, when either of the antimicrobials is used, is of particular concern for the treatment of S. maltophilia infections
Designing strategies for operating Microbial Electrochemical Systems to clean up polluted soils under non-flooded conditions
No full textMicrobial Electrochemical Systems can be setup in soil either for the harvesting of energy from microbial metabolism (sediment microbial fuel cell, SMFC) or for the bioremediation of polluted environments (Microbial Electroremediating Cell, MERC). However, the precieved need for this technology to be located in flooded environments, to assure the ionic contact between anode and cathode, has limited its implementation in standard soils.
This work describes a new configuration that overcomes this limitation by integrating an out-of-soil cathodic chamber with a ceramic barrier so a closed circuit system can be achieved without flooding the soil. On top of harvesting energy under this new configuration we have outperformed natural bioremediation by restoring an atrazine polluted soil as proof of concept. Our results showed that >98% of the initially available atrazine was efficiency removed after 2 weeks with this new MERC configuration, in contrast with a mere 58% removal obtained under natural attenuation. Moreover, a set of toxicological tests using green algae, Salmonella typhimurium and Sorghum saccharatum strongly confirmed a marked lack of toxicity in the soil after the bioelectrochemical treatment in contrast with the natural attenuation that was unable to fulfill the non-toxic level
Mixed Matrix Polytetrafluoroethylene/Polysulfone Electrospun Nanofibrous Membranes for Water Desalination by Membrane Distillation
No full textThe electrospinning technique was used successfully to fabricate nanofibers of polysulfone (PSF) in which polytetrafuoroethylene nanoparticles (PTFE NPs) were embedded. The size of the PTFE NPs is only 1.7 to 3.6 times smaller than the nanofiber diameter. The transition from hydrophobic to superhydrophobic character of the bead-free PSF electrospun nanofiber mats occurred with a PTFE NPs loading in the range 12-18% of the PSF weight. Transmission electron microscopy images revealed protruding nanosized asperities on the fiber surface due to the embedded PTFE NPs in the PSF matrix. For low PTFE NPs content in PSF matrix (<6% of the polymer weight), the PTFE NPs were arranged one by one in a single file along the PSF nanofiber axis. The structural characteristics of the nanofibers and electrospun nanofibrous membranes (ENMs) were studied by means of different techniques and their relationship with the PTFE NPs loading in PSF were discussed. The PSF/PTFE ENMs were tested in desalination by direct contact membrane distillation (DCMD) and the obtained performance was discussed in terms of the ENMs structural characteristics. Competitive permeate fluxes, as high as 39.5 kg/m(2)h, with stable low permeate electrical conductivities (<7.145 mu S/cm) for 30 g/L NaCl aqueous solution and transmembrane temperature of 60 degrees C were achieved without detecting any interfiber space wetting
Toward sustainable environmental quality: Priority research questions for Europe
No full textThe United Nations’ Sustainable Development Goals have been established to end poverty, protect the planet, and ensure prosperity for all. Delivery of the Sustainable Development Goals will require a healthy and productive environment. An understanding of the impacts of chemicals which can negatively impact environmental health is therefore essential to the delivery of the Sustainable Development Goals. However, current research on and regulation of chemicals in the environment tend to take a simplistic view and do not account for the complexity of the real world, which inhibits the way we manage chemicals. There is therefore an urgent need for a step change in the way we study and communicate the impacts and control of chemicals in the natural environment. To do this requires the major research questions to be identified so that resources are focused on questions that really matter. We present the findings of a horizon‐scanning exercise to identify research priorities of the European environmental science community around chemicals in the environment. Using the key questions approach, we identified 22 questions of priority. These questions covered overarching questions about which chemicals we should be most concerned about and where, impacts of global megatrends, protection goals, and sustainability of chemicals; the development and parameterization of assessment and management frameworks; and mechanisms to maximize the impact of the research. The research questions identified provide a first‐step in the path forward for the research, regulatory, and business communities to better assess and manage chemicals in the natural environment. Environ Toxicol Chem 2018;37:2281–2295
Results from a first optimization study of a photovoltaic and solar disinfection system (SOLWAT) for simultaneous energy generation and water purification
No full textThe SOLWAT system, integrating the functions of photovoltaic electricity generation and solar disinfection, was subjected under a microbial kinetic study with the aim of applying system optimizations. E. coli, total coliforms, Enterococcus spp and Clostridium perfringens response and photovoltaic performance vs. conventional PET bottles was studied using river water sources and natural sunlight. Results showed that under strong climatic conditions the time required for the solar disinfection could be reduced by half in the SOLWAT system (3h), increasing the quantity of treated water and favouring the SOLWAT power output due to the cooling effect of the water being purified on the top of the PV module, which is maximum during the beginning of the SODIS process, so the module could be benefited from lower operational temperatures when using reduced treatments times
Behind the Scenes: Mechanisms Regulating Climatic Patterns of Dissolved Organic Carbon Uptake in Headwater Streams
No full textLarge variability in dissolved organic carbon (DOC) uptake rates has been reported for headwater streams, but the causes of this variability are still not well understood. Here we assessed acetate uptake rates across 11 European streams comprising different ecoregions by using whole‐reach pulse acetate additions. We evaluated the main climatic and biogeochemical drivers of acetate uptake during two seasonal periods. Our results show a minor influence of sampling periods but a strong effect of climate and dissolved organic matter (DOM) composition on acetate uptake. In particular, mean annual precipitation explained half of the variability of the acetate uptake velocities (VfAcetate) across streams. Temperate streams presented the lowest VfAcetate, together with humic‐like DOM and the highest stream respiration rates. In contrast, higher VfAcetate were found in semiarid streams, with protein‐like DOM, indicating a dominance of reactive, labile compounds. This, together with lower stream respiration rates and molar ratios of DOC to nitrate, suggests a strong C limitation in semiarid streams, likely due to reduced inputs from the catchment. Overall, this study highlights the interplay of climate and DOM composition and its relevance to understand the biogeochemical mechanisms controlling DOC uptake in streams
La Geomática en el análisis de los recursos hídricos/Geomatics in water resources analysis
No full textEl número de programas y aplicaciones informáticas que existen relacionadas con todos los temas y problemáticas de los recursos hídricos son muy diversos. Es, por tanto, necesario realizar un exhaustivo trabajo de evaluación de sus prestaciones previo a su instalación como potenciales recursos de permanente uso, sobre todo cuando se pretende que los programas sean de libre acceso y de naturaleza espacial para ser incorporados en infraestructuras de análisis hidrológico.
Los programas que aparecen en este libro son los que forman parte del Laboratorio de Geomática de IMDEA Agua. Uno de los objetivos de la Unidad de Geomática es optimizar los recursos y, de este modo, está creciendo el interés y el número de software libres con los que trabajan los diferentes investigadores del centro.
El contenido de este documento, tras una breve introducción sobre la Geomática y los programas de libre acceso aplicados en hidrología, se ha dividido en las siguientes temáticas en función de los tipos de programas con los que se trabaja más comúnmente:
1. Sistemas de Información Geográfica (SIG)
2. Modelos hidrológicos, hidráulicos y hidrogeomorfológicos (eorsión)
3. Tratamiento de imágenes 4. Estadística y Geoestadística
5. Calidad cartográfica
6. Programas de apoyo
La organización de la información de cada uno de los programas es la siguiente:
1. Descripción: introducción y rasgos generales del programa, historia del mismo y ejemplos de campos de investigación que lo emplean.
2. Características técnicas: se muestra una tabla con distintos atributos sobre el programa tales como sistema operativo que soporta, versión del programa, características principales, etc.
3. Ejemplos de trabajos científicos que han usado el programa como parte de su investigación divididos en una serie de categorías temáticas específicas.
4. Bibliografía de los trabajos expuestos en los apartados anteriores a modo de información complementaria o ampliación.
De esta manera se han expuesto los diferentes programas empleados en el mundo de la investigación ligado con las ciencias de la Tierra y, más específicamente, con los recursos hídricos. Algunos de estos programas no han sido concebidos como aplicaciones específicas para el análisis de los recursos hídricos y la modelización hidrológica sino que son más generalistas. Algunos de ellos son los SIG, que se emplean en un amplio abanico de problemáticas y los considerados aquí como programas de apoyo, como los de análisis estadísticos o los que se relacionan con la minería de datos y los sistemas de apoyo a la decisión.
Por lo tanto, Cuadernos de Geomática 6 pretende ser un manual de software, centrado en los programas de acceso libre de análisis espacial, que son necesarios para poder hacer una evaluación completa e integral de las problemáticas ambientales asociadas a los recursos hídricos
Análisis de ciclo de vida en la economía circular. Aplicaciones en el reciclaje de tecnología de membrana
No full textCompra Pública Verde es un libro colectivo que analiza la incorporación de criterios ambientales a la contratación pública en el marco de las nuevas Directivas de contratación pública (2014) y su transposición al Derecho español mediante la Ley 9/2017, de 8 de noviembre, de Contratos del Sector Público (LCSP). En sintonía con lo establecido en la LCSP, se analiza la inclusión de exigencias ambientales durante todo el iter contractual (solvencia, certificados de gestión ambiental, etiquetas ecológicas, prohibiciones de contratar, criterios de adjudicación, coste del ciclo de vida, condiciones especiales de ejecución), incluido su control por los Tribunales Administrativos de recursos contractuales. En su segunda parte, el libro recoge una serie de trabajos y estudios sobre el análisis del ciclo de vida (ACV) —directamente relacionadas con las externalidades ambientales que refiere el legislador europeo— y cuyo acabado conocimiento resulta una tarea insoslayable para la CPV.
CPV es una obra de referencia en esta nueva época de una contratación pública estratégica y más eficiente, donde lo ecológico se convierte en un eje irrenunciable en las decisiones públicas
OPINION ON the public health impacts and risks resulting from onshore oil and gas exploration and exploitation in the EU
No full textThe SCHEER was requested to assess public health risks resulting from onshore oil and gas exploration and extraction activities on a commercial scale in the EU, and to identify knowledge gaps. Onshore oil and gas exploration and exploitation can induce increased human exposure to biocides, scale and corrosion inhibitors, oxygen scavengers, surfactants, and various hydrocarbons such as Volatile Organic Compounds (VOCs), polycyclic aromatic hydrocarbons (PAH), as well as particulate matter and noise in surrounding populations. Another consequence of onshore oil and gas exploration and exploitation relates to seismic activity: the level of evidence linking this phenomenon to onshore oil and gas exploration and extraction is moderate to strong. Some of these environmental factors are recognised carcinogens or contribute to the risk of other chronic diseases such as cardiovascular or neurological illnesses. Epidemiological studies have tried to characterise the possible impact of emissions from onshore oil and gas exploration and exploitation on human health; the vast majority of these studies are from outside the EU, generally the USA. They have relied on relatively imprecise exposure estimates, which is likely to lead to attenuation of dose-response functions. These studies indicate that the risk of haematological cancers and of preterm delivery may be higher in populations living around onshore oil and gas exploration and exploitation sites in comparison to populations living further away. The corresponding level of evidence is weak to moderate. A complete quantified risk assessment cannot be undertaken given the existing limited knowledge base but existing risk assessment studies show some coherence with the associations found in epidemiological studies. The SCHEER is surprised at the very limited scientific assessment and monitoring of both the environment and people’s health near long-established onshore oil and gas exploration and exploitation sites in the EU, given the numerous studies conducted on similar American oil and gas exploration and exploitation activities and the amount of scientific evidence pointing towards possible adverse effects of these activities. The review undertaken by the SCHEER suggests a number of knowledge gaps that could be addressed through the following actions: (i) development of a centralised and harmonised inventory of all oil and gas exploration and exploitation sites in the EU; (ii) conduct of analytical and modelling studies that identify, quantify and characterise exposure mixtures and their levels in the vicinity of these sites; (iii) initiation of targeted biomonitoring and exposure assessment studies of populations potentially at risk; (iv) implementation of large-scale epidemiological studies with accurate exposure assessment and (v) carrying out of quantitative risk assessment studies