Estimación de la recarga en lechos fluviales mediante sondas TDR flexibles durante eventos de avenida (Río Andarax, Almería)

Acta de las VIII Jornadas de Investigación de la Zona no Saturada del Suelo (Córdoba, España - 2007)[ES] En este trabajo se describe la metodología y la instrumentación instalada en el cauce fluvial para la medida de la infiltración directa en la zona no saturada asociada a las crecidas en el río Andarax (Almería), y se presentan los datos preliminares registrados en el primer año de funcionamiento de la estación. El objetivo final de este seguimiento es cuantificar la recarga a largo plazo de los acuíferos aluviales someros, asociada a eventos de crecida. La estación de medida se localiza en las proximidades de la localidad de Gádor, y permite el registro de los contenidos de humedad en la zona no saturada mediante sondas TDR flexibles (15 en total) hasta los 10 m de profundidad. Igualmente, se dispone de sondas para el registro del niveles del agua superficial durante la crecida y de las variaciones del nivel piezométrico. Los resultados preliminares muestran claramente que la metodología utilizada permite obtener datos de infiltración en la zona no saturada del suelo de manera continua y en tiempo real con mínimas perturbaciones de suelo. El registro de un evento ocurrido el 7 de Enero de 2006, de duración estimada de 7 días y cuyo calado máximo se ha registrado en 7 cm, permite demostrar que el hidrograma de crecida tiene una respuesta clara en el contenido de humedad del suelo en el perfil estudiado, con aumentos de hasta el 5% de humedad en sondas a profundidades superiores a 9 m. Analizando los cambios ocurridos en el nivel freático podemos comprobar que los datos obtenidos en el perfil estudiado son extrapolables al conjunto de la zona no saturada y con ello elaborar una estimación de la recarga.[EN] This work describes the methodological procedure and the instrumentation installed to monitor the infiltration through the vadose zone associated with flood events of the Andarax River (Almeria). First, the preliminary data recorded in the station’s first functional year are presented and discussed. The final objective of this monitoring was to quantify the long-term shallow alluvial aquifer recharge related to flooding. The monitoring station is located near Gador, and records the moisture contents through the vadose profile using 15 flexible TDR probes (FTDR) reaching depths of 10 m. In addition, water surface and groundwater piezometric levels are recorded. The preliminary results clearly show that the methodology chosen permits the collection of real time and continuous infiltration data in the vadose zone with minimum soil disturbances. The 7 January 2006 event recorded, 7 days in length and whose maximum flood height recorded was 7 centimeters, demonstrated that the flood hydrograph gave a clear response in the soil moisture content of the profile studied, with increases in soil water content of up to 5% for soil depths below 9 meters. Analyzing the changes in the ground water level it is obvious that the infiltration data can be applied to the whole vadose zone and therefore the aquifer recharge can be estimated.Este trabajo se ha realizado con la financiación del Proyecto Europeo WADE (FloodWater recharge of alluvial Aquifers in Dryland Environments, contrato no. GOCE-CT-2003-506680), y del proyecto CICYT PALEOREC “Infiltración en lechos fluviales y recarga de acuíferos relacionadas con avenidas y paleocrecidas en ríos efímeros” (Proyecto CGL2005-01977/HID).Peer reviewe

C-reactive protein serum levels as an early predictor of outcome in patients with pandemic H1N1 influenza A virus infection

<p>Abstract</p> <p>Background</p> <p>Data for predicting which patients with pandemic influenza A (H1N1) infection are likely to run a complicated course are sparse. We retrospectively studied whether the admission serum C-reactive protein (CRP) levels can serve as a predictor of illness severity.</p> <p>Methods</p> <p>Included were all consecutive adult patients who presented to the emergency department (ED) between May-December, 2009 with a flu-like illness, a confirmed diagnosis of pandemic influenza A (H1N1) infection and a serum CRP level measured within 24 hours of presentation. Patients with a proven additional concurrent acute illness (e.g., bacteremia) were excluded. We used the ROC curve analysis, Kaplan-Meier curves and the Cox proportional hazard model to evaluate the predictive ability of CRP as a prognostic factor.</p> <p>Results</p> <p>Seventeen (9%) of the 191 enrolled patients were admitted to the intensive care unit (ICU), of whom eight (4%) required mechanical ventilation and three (2%) died. The median admission serum CRP levels were significantly higher among patients who required subsequent ICU care and mechanical ventilation than among patients who did not (123 mg/L and 112 mg/L vs. 40 mg/L, <it>p </it>< .001 and 43 mg/L, <it>p </it>= .017, respectively). A Cox proportional hazard model identified admission serum CRP levels and auscultatory findings over the lungs as independent prognostic factors for ICU admission. Admission serum CRP levels were the only independent prognostic factor for mechanical ventilation. Thirty days after presenting to the ED, none of the patients with admission serum CRP level <28 mg/L (lower tertile) required either ICU admission or mechanical ventilation. At the same time point, 19% of the patients with admission serum CRP level ≥70 mg/L (upper tertile) needed to be admitted to the ICU and 8% of the same upper tertile group required mechanical ventilation. The differences in the rates between the lower vs. upper tertile groups were significant (Log-Rank <it>p </it>< .001 for ICU and <it>p </it>< .024 for mechanical ventilation).</p> <p>Conclusions</p> <p>In our study group, serum CRP levels obtained in the early ED admission stage from patients presenting with pandemic H1N1 influenza A infection were found to serve as a useful gauge for predicting disease course and assisting in patient management.</p

The Soreq Applied Research Accelerator Facility (SARAF) - Overview, Research Programs and Future Plans

The Soreq Applied Research Accelerator Facility (SARAF) is under construction in the Soreq Nuclear Research Center at Yavne, Israel. When completed at the beginning of the next decade, SARAF will be a user facility for basic and applied nuclear physics, based on a 40 MeV, 5 mA CW proton/deuteron superconducting linear accelerator. Phase I of SARAF (SARAF-I, 4 MeV, 2 mA CW protons, 5 MeV 1 mA CW deuterons) is already in operation, generating scientific results in several fields of interest. The main ongoing program at SARAF-I is the production of 30 keV neutrons and measurement of Maxwellian Averaged Cross Sections (MACS), important for the astrophysical s-process. The world leading Maxwellian epithermal neutron yield at SARAF-I ($5\times 10^{10}$ epithermal neutrons/sec), generated by a novel Liquid-Lithium Target (LiLiT), enables improved precision of known MACSs, and new measurements of low-abundance and radioactive isotopes. Research plans for SARAF-II span several disciplines: Precision studies of beyond-Standard-Model effects by trapping light exotic radioisotopes, such as $^6$He, $^8$Li and $^{18,19,23}$Ne, in unprecedented amounts (including meaningful studies already at SARAF-I); extended nuclear astrophysics research with higher energy neutrons, including generation and studies of exotic neutron-rich isotopes relevant to the rapid (r-) process; nuclear structure of exotic isotopes; high energy neutron cross sections for basic nuclear physics and material science research, including neutron induced radiation damage; neutron based imaging and therapy; and novel radiopharmaceuticals development and production. In this paper we present a technical overview of SARAF-I and II, including a description of the accelerator and its irradiation targets; a survey of existing research programs at SARAF-I; and the research potential at the completed facility (SARAF-II).Comment: 32 pages, 31 figures, 10 tables, submitted as an invited review to European Physics Journal

In Situ Bioremediation of a Gasoline-Contaminated Vadose Zone: Implications from Direct Observations

In situ bioremediation of a contaminated vadose zone requires implementing hydraulic and chemical conditions that stimulate the development of indigenous bacteria capable of degrading contaminants in the subsurface. We investigated enhanced biostimulation of a gasoline-contaminated deep vadose zone through nutrient- and O–amended water infiltration. A vadose zone monitoring system (VMS) provided real-time observations of the treatment process’s effect on hydrocarbon attenuation. The VMS data included continuous measurements of variations in water content, concentrations and isotopic compositions of methyl -butyl ether and benzene, toluene, ethylbenzene, and xylene in pore-water and gas phases, and concentrations of O and CO in the vadose zone gas phase. Real-time observations from the unsaturated zone enabled interactive adjustment of the remediation strategy and improved biostimulation conditions for biodegradation of the target compounds. In the course of three infiltration events that included infiltration of an O– and nutrient-enriched water solution, a significant reduction in contaminant mass was observed across the unsaturated zone

Transport of photosystem II (PS II)–inhibiting herbicides through the vadose zone under sugarcane in the Wet Tropics, Australia

The usage of Photosystem II (PS II)–inhibiting herbicides, identified as a risk to ecosystem health and resilience, has been reduced in agricultural activities adjacent to the Great Barrier Reef, Australia over the past 10 years. Two PS II herbicides (diuron and hexazinone) and three metabolites (desethyl atrazine, hydroxyatrazine and DCPMU) were recently detected at low concentrations in the regional aquifer of the South Johnstone River sub-basin, in the Wet Tropics, Australia. This study presents results from monitoring 12 PS II herbicides in soil profile, porewater sampled through the vadose zone monitoring system, and groundwater from bores. Among the 12 PS II herbicides, only hexazinone and metribuzin were applied relatively recently, in November 2014. Hexazinone exhibited substantial transport through the vadose zone, with decreasing concentration with depth, and eventually disappeared over-time. Metribuzin was not detected in the groundwater, in soil profile or through the vadose zone. Diuron was detected in the soil profile, through the vadose zone and in bores at the site. Its two metabolites—1-(3,4-dichlorophenyl)-3-methylurea (DCPMU) and 3,4-dichloroaniline—were detected in the deepest port at 4 m, indicating the transformation of diuron into these metabolites and potential leaching. The other nine PS II herbicides were not detected in the soil profile, through the vadose zone or in bores at the site. Some of the PS II herbicides were detected in the soil profile and beyond the root zone, depending on their application record and persistence in the environment. Therefore, the data shows that the herbicides are long lived at low concentrations. However, herbicide concentrations in subsoil, vadose zone and groundwater are low (less than environmental guideline values) and are detected at much lower concentrations than in surface runoff.</p

Pesticide transport through the vadose zone under sugarcane in the Wet Tropics, Australia

Photosystem II (PS II) pesticides, recognized as a threat to ecological health, were targeted for reduction in sugarcane farming in Great Barrier Reef (GBR) catchments. Alternative herbicides, the non-PS II herbicides (including glyphosate, paraquat, 2,4-D, imazapic, isoxaflutole, metolachlor, and S-metolachlor), continue to be used in these catchments. However, the potential ecological fate, transport, and off-site environmental effects of non-PS II herbicides, with respect to their usage scheme, local rainfall patterns, and infiltration dynamics, have not been investigated previously. A vadose zone monitoring system, instrumented beneath sugarcane land in a GBR catchment, was applied for real-time tracing of pesticide migration across the unsaturated zone, past the root zone during 2017-2019. The regularly applied pesticides (fluroxypyr and isoxaflutole) exhibited substantial migration through the unsaturated zone. Within 1 month of application of fluroxypyr, it leached to 2.87 m depth in the vadose zone, with declining concentrations with depth. Isoxaflutole, which was applied yearly, was found only once, in November 2018, at 3.28 m depth in the soil profile. Other pesticides (imazapic, metolachlor, glyphosate, and haloxyfop) applied during the same period were not detected in the vadose zone. However, imidacloprid, which was not applied at the site during the monitored period, was detected across the entire vadose zone, revealing substantial resistance to degradation. The results show no evidence of any regularly applied pesticides in the site bores at the end of the study, indicating their ultimate degradation within the vadose zone before reaching the groundwater.</p

Real-time detection of ammonium in soil pore water

Abstract The development of technologies for continuous measurement of nitrogen forms in the soil is essential for optimizing the application of fertilizers in agriculture and preventing water-resource pollution. However, there is no effective commercial technology available for continuous monitoring of ammonium species in soil pore water. This work investigates an approach for real-time measurement of ammonium in soil water using near-infrared transmission spectroscopy and partial least squares regression (PLSR) for spectral analysis. The PLSR model was trained using soil pore water collected from various soils spiked with ammonium to achieve a wide concentration range. The monitoring approach was then validated through transport experiments in a soil column. The results demonstrated capabilities for real-time tracking of the temporal variation in soil ammonium concentration and potential utilization in agronomical or environmental sensing

Vadose zone characterisation at industrial contaminated sites

An important challenge faced by environmental practitioners is the estimation of the impact of contamination that is transported from the source of contamination to soil and groundwater at industrial sites. Specifically, quantification of contaminant flux in the vadose zone is challenging due partly to the heterogeneity of the complex porous medium and the preferential flow. Contaminant flux estimations are essential to better establish risk assessment of soil and groundwater as well as to support the selection of remedial measures. Several methods have been developed for contaminant flux estimations in the vadose zone. These methodologies are either based on modelling, on experimental approaches, or on the combination of both, and have been developed principally in the context of agricultural purposes. However, the applicability of such techniques is questioned when it comes to their application to industrial sites, due to differences in depth of investigation, soil origin, contamination and sources. An overview of contaminant flux measurement techniques, together with a potential alternative for improving characterisation techniques and contaminant flux measurement in the vadose zone is presented in this bulletin. The vadose zone experimental setup consists of the combination of the Vadose Zone Monitoring System (VMS) and cross-hole geophysics

Initial data-sets from field experiments on contaminant mass transport and attenuation in the combined soil - vadose zone - groundwater system

In this report, a new system for vadose zone characterization is presented. The Vadose Zone Monitoring System (VMS) allows continuous measurements of water content throughout the vadose zone. In addition, soil water samples can be retrieved at different depths. Such technology is combined with cross-hole geophysics, providing a robust method for subsoil characterization

Monitored tracer experiment using the vadose zone experimental setup (VZES) for studying water and pollutant recharge processes in a brownfield

Contaminant transport characterization in the vadose zone of industrial contaminated sites requires in situ technologies that provide information representative of complex heterogeneous systems. However, finding the appropriate methodology is a challenge, as there is a risk of losing data resolution when capturing the spatial variability of the subsurface. An alternative method is provided by The Vadose Zone Experimental Setup (VZES) which combines surface and cross-borehole geophysical methods with a vadose zone monitoring system (VMS). When geophysical imaging is combined with in-situ hydraulic and chemical information at multiple depths of the vadose zone, detailed characterization of contaminant transport in heterogeneous systems is obtained. The system was installed at an industrial contaminated site in Belgium. A saline tracer infiltration test was performed over a heterogeneous vadose zone composed of backfilled materials underlined by unsaturated fractured chalk. Surface and cross-hole Electrical Resistivity Tomography (ERT) measurements were carried out over a 5 day period, following tracer injection. Results from time-lapse imaging reveal high resistivity variations at 0-0.5m depth, indicating that most of the tracer remained in the upper backfilled deposits. This is coincident with the results from sampled waters across the vadose zone, as no tracer was detected below 0.5m depth. Lower resistivity differences were observed laterally, indicating tracer migration in different directions via preferential flow paths. Lateral migration was found to be dominant over vertical transport in the absence of rain events. Three months after the injection, a geophysical survey was performed and combined with in situ continuous hydraulic and chemical information at multiple depths of the vadose zone. Results from geophysical imaging and water sample analyses indicate vertical movement of the tracer, which reached 4 m depth. Information obtained from continuous measurements of water content reveal that the tracer was transferred via preferential flow. The activation of such flow mechanism occurred as a response to rainfall episodes, resulting in water percolation and tracer transport towards higher depths. The results of the investigations demonstrate that the VZES is an effective method in identifying pathways and mechanisms of transport within a heterogeneous conductivity fields. The implementation of this methodological concept at industrial contaminated sites contributes to improve the development of site conceptual models for soil and groundwater protection and remediation