1,721,011 research outputs found
Informe de personal de apoyo: Lexow, Claudio (2011-2012)
No full textProyectos de investigación en los cuales colabora:
a. Evaluación del riesgo de contaminación en el acuífero freático de la cuenca superior del río Sauce Chico, provincia de Buenos Aire
Informe de personal de apoyo: Lexow, Claudio (2013-2014)
No full textProyectos de investigación en los cuales colabora:
Evaluación del riesgo de contaminación en el acuífero freático de la cuencasuperior del Río Sauce Chico, provincia de Buenos Aire
Glyphosate mobility in piedmont soils of the Australes range in the south of Buenos Aires Province
No full textThe increase in agricultural production is leading to an intensive use of chemical products to improve plant growth. This study of glyphosate soil adsorption took place in an experimental parcel of an agricultural sector of the Buenos Aires province. In this region the product is currently applied in areas of direct sowing and in very small doses. The tests in batch allowed the determination of the partition coefficient Kd, which relates the concentration of glyphosate in the water phase to the adsorbed one in the soil. The Kd coefficient was standardized according to the content of organic matter (Koc), and optimized using models based on the isotherm of Freundlich. The greater degree of adsorption of the glyphosate occurs at surface level and decreases with depth, owing more to variations in the structure and chemical composition of the clay sediments than to the effect of the organic matter. There is a very high adsorption of the glyphosate in the ground so that it would fall into the category of non leachable. This characteristic makes it potentially a little polluting agent, provided conditions of preferential flow that could significantly increase its mobility were not generated.Fil: Lexow, Claudio. Universidad Nacional del Sur; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Morrell, Ignacio. Universitat Jaume I; EspañaFil: Bonorino, Alfredo Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; Argentin
Impact of Urea and Ammoniacal Nitrogen Wastewaters on Soil: Field Study in a Fertilizer Industry (Bahía Blanca, Argentina)
No full textNitrogen compounds in industrial effluents are considered a serious threat to the environment. The aim of this work is to identify the effect produced by nitrogen-rich wastewater on alkaline soils from industrial land. Two plots were irrigated with wastewater as ammoniacal nitrogen (31 to 53 g N m−2) and urea (167–301 g N m−2) sources named P1 and P2, respectively. Inorganic nitrogen (N) concentrations (N-NH3 + N-NH4, N-NO2, N-NO3), soil pH, and N-NH3 volatilization were monitored during a 2-year period. Variations in the fate of N compounds were distinguished according to the quantity and source of N applied to the soil. A higher N input in the form of urea was related to a greater concentration of nitrates and soil acidification in the topsoil (0–30 cm). Otherwise, ammoniacal N wastewater showed greater relative ammonia losses due to volatilization. Ammonia losses were estimated as 24.2% and 7.43% of the total N applied in P1 and P2, respectively. Besides, in P1 ammoniacal N predominated over nitrate, unlike results obtained in P2. The correct management of nitrogen-rich wastewaters in fertilizer industries could greatly reduce soil and groundwater degradation.Fil: Scherger, Leonardo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geología; ArgentinaFil: Zanello, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geología; ArgentinaFil: Lexow, Claudio. Universidad Nacional del Sur. Departamento de Geología; Argentin
Assessment of groundwater contamination risk by BTEX from residual fuel soil phase
Full text linkThe aim of this work is to assess the risk of groundwater contamination associated with BTEX dissolution from fuels as a residual phase. Numerical simulations of sixty scenarios were carried out with the software HYDRUS 2D/3D. Groundwater contamination risk was analyzed given the combination of different porous media textures (silt loam, sandy loam and clay), water fluxes (0.5%, 1% or 3% Rainfall), water table depths (1.5, 2.5, 5 or 8 m below ground surface) and biodegradation rate (active or null). Risk was calculated comparing leachate concentrations to the aquifer and limits established by an international guideline for human drinking water. In all cases, benzene and toluene had the highest mobility in the dissolved phase. Contrary, xylene and ethylbenzene tended to concentrate close to the source zone. These two compounds predominantly concentrated in the solid phase. Calculated risk was proportional to the water flux rate and inversely proportional to the unsaturated thickness. Without biodegradation, in fine-grained sediments risk was very high for shallow aquifers (> 1.5 m depth) and moderate or low for deeper aquifers. However, in sandy loam sediments risk was classified as very high for aquifers up to 8 m deep. When biodegradation was considered, leached concentrations were greatly reduced in the three textures. BTEX concentration in Bahía Blanca City´s aquifer showed acceptable agreement with simulated scenarios. The most sensitive parameters to model results were biodegradation > foc > water table depth > Ks. This study is important for assessing the risks and developing management strategies for fuel contaminated sites.Fil: Zanello, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geología; Argentina. Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Centro de Geología Aplicada, Agua y Medio Ambiente; ArgentinaFil: Scherger, Leonardo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geología; ArgentinaFil: Lexow, Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geología; Argentina. Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Centro de Geología Aplicada, Agua y Medio Ambiente; Argentin
Caracterización geoedafológica necesaria para el diseño de un sistema de riego subsuperficial
No full textEn la República Argentina se considera que el área total irrigada es de 2,1 millones de hectáreas. En la actualidad, se contabilizan en el sudoeste bonaerense instalaciones de una variante del método por goteo. Este consiste en la aplicación de agua a la zona radicular del cultivo por debajo de la superficie del suelo, utilizando cañerías de irrigación enterradas a poca profundidad y emisores de bajo caudal, dispuestos a distancias equidistantes y fijas. El objetivo del presente trabajo fue caracterizar el recurso suelo, teniendo en cuenta principalmente las variables edáficas y geomorfológicas en distintas profundidades, a fin de destacar los aspectos hidráulicos e hidrodinámicos que permitan optimizar el sistema de riego subsuperficial. Se efectuaron mediciones de pH, conductividad eléctrica, porcentaje de carbonatos y granulometría en diez pozos de muestreo, dispuestos estratégicamente en un área de 24 hectáreas. Las variaciones de los parámetros considerados, tanto espacialmente como en profundidad, confirman la necesidad de realizar este tipo de estudios de manera previa a la instalación del sistema para lograr el máximo rendimiento potencial.Fil: Carbajo, Micaela Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Scherger, Leonardo Ezequiel. Universidad Nacional del Sur. Departamento de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Lexow, Claudio. Universidad Nacional del Sur. Departamento de Geología; ArgentinaFil: Zalba, Pablo. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaXXVII Congreso Argentino de la Ciencia del SueloCorrientesArgentinaAsociación Argentina Ciencia del SueloUniversidad Nacional del Nordeste. Facultad de Ciencias AgrariasInstituto Nacional de Tecnología AgropecuariaConsejo Federal de InversionesMinisterio de Producción de Corriente
Identifying optimal monitoring strategies to predict soil hydraulic characteristics and water contents by inverse modeling
Full text linkAim of study: To investigate the monitoring strategies that let us to build effective models able to best estimate water contents, θ and pressure heads, h with the least amount of data. Area of study: Field data was acquired in an experimental plot at Bahía Blanca (Argentina). Material and methods: Field data of θ(t), h(t) for six soil depth were used to optimize the SHP (θr, θs, α, n and Ks) by inverse modeling with HYDRUS 1D. Several scenarios of available data from θ(t) and h(t) were considered: (1) six monitoring depths (6-MD); (2) five monitoring depths (5-MD); (3) four monitoring depths (4-MD). Model accuracy was assessed by comparing the measured and predicted θ and h for each monitoring strategy. Additionally, field measured SHP with independent methods were compared to inversely optimized SHP. Main results: The best fit between predicted and observed θ and h was achieved with the 6-MD strategy. Nevertheless, deterioration of statistics EF and rRMSE in the 5-MD or 4-MD schemes were lower than 10%, depending on the location of the missing data. The observation points that had less importance in parameter prediction corresponded to the intermediate vadose zone and to the deeper layers. The proposed strategies presented a better performance than field measured SHP to reproduce soil water retention curves for each layer of the soil profile. Research highlights: By reducing the number of vertical observations in the profile without harming the final SHP estimation, the resources needed in data monitoring strategies can be greatly enhanced.Fil: Scherger, Leonardo Ezequiel. Universidad Nacional del Sur. Departamento de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Valdes Avellan Javier. Universidad de Alicante; EspañaFil: Lexow, Claudio. Universidad Nacional del Sur. Departamento de Geología; Argentin
A theoretical model for predicting the behaviour of btex in the unsaturated zone and groundwater
Full text linkFuelling stations are one of the most important forms of soil and groundwater contamination in urban areas around the world. In this work, a mathematical model was applied to assess the risk of physical media contamination (water, air and soil). The model is based on the chemical fuel and hydrological properties of each site. The group of hydrocarbons selected for applying the model were monoaromatic hydrocarbons: benzene, toluene, ethylbenzene and xylenes (BTEX). A mathematical model was used to evaluate the behavior of each compound in each partitioning phase (non aqueous liquid phase, dissolved, volatile and retained). Furthermore, it was analyze which compound has more affinity for each phase. Finally, mass flux of BTEX reaching groundwater was calculated according to steady flow under two different conditions: (1) considering only sorption and volatilization, and (2) adding biodegradation. In this study, it could be demonstrated that modeling BTEX behavior in soil gave good results for urban areas. The methodology applied in this work could be extrapolated to any site of the world with the same problematic. Particularly, the model could be used to determine the distribution of BTEX in the soil profile. Moreover, results exhibit that dissolution is the main process affecting BTEX transport in areas containing reduced unsaturated zones (less than two meters). Otherwise, when water table is placed at deeper depths, contaminants are predominately retained in soil. In all cases, the lowest proportion of BTEX were in the volatile phase. Using this information, zones with high and low risk of contamination could be easily defined in the city of Bahia Blanca, Argentina.Fil: Zanello, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Centro de Geología Aplicada, Agua y Medio Ambiente; ArgentinaFil: Scherger, Leonardo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geología; ArgentinaFil: Carbajo Castoldi, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Lexow, Claudio. Universidad Nacional del Sur. Departamento de Geología; Argentina. Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Centro de Geología Aplicada, Agua y Medio Ambiente; Argentin
Modeling fate and transport of ammonium, nitrite, and nitrate in a soil contaminated with large dose of urea
No full textSoil or groundwater potential contamination generated by urea spills during its manufacture process is unknown. The aim of this work is determining the fate and transport of Nitrogen (N) species (ammonia, nitrites, and nitrates) when high doses of urea are spilled on to the soil surface. Fertilizer concentrations applied to soil surface were in the range from 167 to 301 g N m−2. HYDRUS 2D was applied to simulate N-species transport in the unsaturated zone. Simulated soil water contents correctly represent field measurements during the period March 2018–December 2019 (rRMSE = 0.099). Measured and simulated concentrations of N–NH4+, N–NO2−, and N–NO3− presented a general r2 of 0.76 and RMSE of 0.0435 mg g−1 (rRMSE = 0.096). A considerable decrease in soil pH was observed after urea application. Simulated N losses by volatilization were found in the range of 7.9–13.3% of total urea-N input, in agreement with field measured quantities. According to N mass balance the predominant species are ammonium and nitrate. After hydrolysis of urea, nitrification is the dominant process in soil. At the end of the experiment, ammonium corresponded to 22% of total urea-N input, majorly concentrated in the first forty centimeters of soil profile. Otherwise, nitrate represented 52.7% of total urea-N input. Although simulated quantities of N–NO3− leached into the aquifer are negligible (0.23 g m−2), a significant solute load remains in soil, which could be mobilize in the future. Numerical modeling of N transport is a fundamental tool to predict and evaluate the characteristics of a pollutant event of this nature.Fil: Scherger, Leonardo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geología; ArgentinaFil: Zanello, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geología; ArgentinaFil: Lafont, Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geología; ArgentinaFil: Lexow, Claudio. Universidad Nacional del Sur. Departamento de Geología; Argentina. Comisión de Investigaciones Científicas. Centro de Geología Aplicada, Agua y Medio Ambiente; Argentin
Comparação da abordagem de modelagem inversa e métodos tradicionais para estimar as propriedades hidráulicas insaturadas em solo franco arenoso
Full text linkThe aim of this work is to compare the use of the inverse solution approach in the estimation of soil hydraulic properties with traditional tension disk infiltrometer (TDI) data analysis, field retention data and commonly used pedotransfer functions (PTFs). Field data were collected in an experimental plot located at Bahía Blanca, Argentina. Field infiltration under saturated conditions was measured by the inverse auger hole method and infiltration under unsaturated condi-tions were carried out with TDI. Field retention data (θ(h)) were also collected periodically. The HYDRUS 2D/3D software was used to optimize soil hydraulic parameters by inverse solution according to TDI data. The saturated hydraulic con-ductivity measured by inverse auger hole method (5.53 cm.h-1) and calculated by Wooding analytical approach (5.35 cm.h-1) and inverse numerical simulations (5.36 cm.h-1) showed very close values. According to macroporosity esti-mates infiltrated water is mainly conducted through soils micro and mesopores. Macropores only channeled 15.9% of total infiltrated flow. Soil water retention curves (SWRC) predicted by PTFs did not represented correctly field retention data. The best adjustment between water content at specific pressure heads predicted by SWRCs and field measured water content was reached by the TDI inverse solution approach (RMSE: 0.050 cm3.cm-3). The inverse solution approach probed to be a simple and practical method to obtain an accurate estimate of both, SWRC and hydraulic conductivity curve.O objetivo deste trabalho é comparar o uso da solução inversa na estimativa das propriedades hidráulicas do solo com a análise tradicional de dados por infiltrômetro de disco de tensão (IDT), dados de retenção em campo e funções de pedotransferência (FPTs) comumente usadas. Os dados de campo foram coletados em uma parcela experimental lo-calizada em Bahía Blanca, Argentina. A infiltração no campo sob condições saturadas foi medida pelo método do furo inverso e a infiltração sob condições insaturadas foi realizada com IDT. Os dados de retenção de campo (θ(h)) também foram coletados periodicamente. O software HYDRUS 2D/3D foi utilizado para otimizar os parâmetros hidráulicos do solo por solução inversa, de acordo com os dados do IDT. A condutividade hidráulica saturada medida pelo método do furo inverso (5.53 cm.h-1) e calculada pela abordagem analítica de Wooding (5.35 cm.h-1) e simulações numéricas inversas (5.36 cm.h-1) mostraram valores muito próximos. Segundo estimativas de macroporosidade, a água infiltrada é conduzida principalmente através de microporos e mesoporos do solo. Os macroporos canalizaram apenas 15.9% do fluxo total infiltrado. As curvas de retenção previstas pelos FPTs não representaram corretamente os dados de retenção em campo. O melhor ajuste entre o teor de água nas tensões específicas previstas pelas curvas de retenção e o teor de água medido no campo foi alcançado pela abordagem de solução inversade IDT (RMSE: 0.050 cm3.cm-3). A abordagem de solução inversa demonstrou ser um método simples e prático para obter uma estimativa precisa de curvas de re-tenção e de condutividade hidráulica.Fil: Scherger, Leonardo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geología; ArgentinaFil: Zanello, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Centro de Geología Aplicada, Agua y Medio Ambiente; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Lexow, Claudio. Universidad Nacional del Sur. Departamento de Geología; Argentin
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