Advanced search


Knowledge area




48 results, page 1 of 5

Disponibilidad de Pb, Cd y Ni por la adición de fósforo y azufre en suelos regados con agua residual, en el Valle del Mezquital, Hidalgo

MARTIN SOLIS MARTINEZ (2014)

Tesis (Doctorado en Ciencias, especialista en Edafología).- Colegio de Postgraduados, 2014.

Se evaluó el efecto de la adición de azufre y fósforo sobre la extractabilidad de Pb, Cd y Ni, y en la biodisponibilidad para maíz y alfalfa en el valle del Mezquital, Hidalgo. Se muestrearon los suelos de 13 sitios, se caracterizaron física y químicamente y se determinaron los elementos potencialmente tóxicos totales y extractables. De estos suelos se seleccionaron tres (Atitalaquia, Tlahuelilpan y Tepatepec) para establecer experimentos de equilibrio en el laboratorio. Los suelos se incubaron con dosis crecientes de azufre (0, 2, 4 y 6 t ha-1) y fósforo (0, 250, 500, 1000 y 2000 mg L-1), durante cinco y dos semanas, respectivamente. Se cuantificó la concentración de Pb, Cd y Ni, unidos a las diferentes fracciones del suelo (soluble, FI; intercambiable, FII; carbonatos, FIII; óxidos, FIV; materia orgánica, FV, y residual, FVI). En el caso del plomo, las fracciones FVI, FIV y FIII fueron las más estables en los tres suelos. El tipo de suelo, así como la adición de azufre y fósforo, afectaron significativamente a la FII. Las fracciones de Cd más estables resultaron ser FVI, FII y FV. La adición de S y P a los suelos disminuyó el contenido de Cd en la fracción ligada a los carbonatos (FIII). Las fracciones de níquel FVI, FV y FIII fueron las más estables en los tres sitios. Al aplicar azufre y fósforo a los suelos, se observó un incremento en las fracciones FI, FII y FV. Con base en los experimentos del laboratorio, se seleccionaron los tratamientos 0 y 2 t ha-1 de azufre, y 0, 1000 y 2000 mg L-1 de fósforo, para realizar el experimento en invernadero y evaluar la biodisponibilidad de los metales para maíz blanco y alfalfa valenciana. Los tres suelos se incubaron con azufre y fósforo durante cuatro y dos semanas, respectivamente. Las plantas que crecieron en distintos suelos tuvieron diferente contenido de plomo y cadmio. La concentración de Ni en maíz sobrepasó los intervalos considerados como normales para los cultivos. La adición de azufre y fósforo redujo el contenido de Pb en la alfalfa; incrementó el contenido de Cd y Ni, pero disminuyó el rendimiento total de materia seca. El tipo de suelo influyó en la concentración de Pb, Cd y Ni en el tejido de alfalfa. Se seleccionaron y analizaron por difracción de rayos x algunas muestras de suelo con diferentes tratamientos de azufre y fósforo, identificando diversos minerales conteniendo Pb, Cd y Ni. _______________ AVAILABILITY OF Pb, Cd and Ni BY THE ADDITION OF PHOSPHORUS AND SULFUR SOILS IRRIGATED WITH WASTE WATER, IN THE MEZQUITAL VALLEY, HIDALGO. ABSTRACT: The effect of the addition of sulfur and phosphorus on the extractability of Pb, Cd and Ni were evaluated, and bioavailability to corn and alfalfa in the Mezquital Valley, Hidalgo. Soils were sampled 13 sites were characterized physically and chemically extractable and total and potentially toxic elements were determined. Of these soils three (Atitalaquia, Tlahuelilpan and Tepatepec) were selected to establish equilibrium experiments in the laboratory. Soils were incubated with increasing doses of sulfur (0, 2, 4 and 6 t ha-1) and phosphorus (0, 250, 500, 1000 and 2000 mg L-1) for five and two weeks, respectively. The concentration of Pb, Cd and Ni was quantified, it attached to the different soil fractions (soluble, FI; interchangeable, FII, carbonates, FIII, oxides, FIV, organic matter, FV, and residual, FVI). In the case of lead, the FVI, FIV and FIII fractions were more stable in the three soils. The type of soil and the addition of sulfur and phosphorus significantly affect FII. Fractions were found to be more stable Cd FVI, FII and FV. The addition of S and P to soils decreased Cd content in the carbonate bound fraction (FIII). FVI nickel fractions, FV and FIII were most stable at the three sites. By applying nitrogen and phosphorus to the soil, an increase was observed in FI, FII and FV fractions. Based on laboratory experiments, treatments 0 were selected and 2 t ha-1 sulfur, and 0, 1000 and 2000 mg L-1 phosphorus to make the greenhouse experiment and evaluate the bioavailability of metals on white corn and valenciana alfalfa. The three soils were incubated with sulfur and phosphorus for four and two weeks respectively. Plants grown in different soils showed different content of lead and cadmium. The Ni concentration in maize surpassed intervals considered normal for crops. The addition of sulfur and phosphorus reduced the Pb content in alfalfa increased the content of Cd and Ni, but decreased the total dry matter yield. Soil type influenced the concentration of Pb, Cd and Ni in the tissue of alfalfa. Were selected and analyzed by x-ray diffraction soil samples with different treatments of sulfur and phosphorus, identifying various minerals containing Pb, Cd and Ni.

Doctoral thesis

Elementos potencialmente tóxicos Extracción secuencial Alfalfa Maíz Difracción de rayos x Potentially toxic elements Sequential extraction Corn X-ray diffraction Edafología Doctorado CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

LOS PARQUES COMO ELEMENTOS DE SUSTENTABILIDAD DE LAS CIUDADES

JUAN PABLO RAMIREZ SILVA (2010)

The place where we live can become a very different place from what existed years ago, urbanization is a process that is transformed in the environment in a drastic way and sometimes a very fast pace, a degree such that it is difficult for can conceive the city as an ecosystem in itself; However, the city becomes the center of a whole network of interactions, so diverse that it is capable of impacting the region, embodying its ecological footprint. This "urban ecosystem" is made up of at least four basic nuclei, 1) The mining areas, 2) The rural areas, 3) The areas of neighboring settlements and 4) The natural areas (Camargo, 2008).

El lugar en el que vivimos, puede convertirse en un sitio muy distinto al que originalmente existía años atrás, pues la urbanización es un proceso que transforma el entorno de manera drástica y a veces a un ritmo muy acelerado, a tal grado que es difícil que podamos concebir a la ciudad como un ecosistema en sí mismo; Sin embargo, la ciudad constituye el centro de toda una red de interacciones, tan diversas que es capaz de impactar la región, plasmando en ella su huella ecológica. Este “ecosistema urbano”, está constituido por al menos cuatro núcleo básicos, 1) Las áreas mineras, 2) Las áreas rurales, 3) Las áreas de asentamientos vecinos y 4) Las áreas naturales (Camargo, 2008).

Article

parques elementos sustentabilidad ciudades parks elements sustainability cities BIOLOGÍA VEGETAL (BOTÁNICA) BIOLOGÍA Y QUÍMICA

Factors Associated with the Rejection of the Vaccine against Human Influenza

Andrés Salas Casas Raúl Azael Agis Juárez Josefina Reynoso Vázquez Jesús Carlos Ruvalcaba Ledezma (2015)

Food demand for the world population, economic development and population growth has required food production on a larger scale. In order to ensure production the use of predominantly organophosphate and carbamate pesticides in agricultural and health activities has been increased (Cortez Genchi, et al., 2008)

The aim of the investigation consists on describing the toxic impact of pesticides, as well as analyzing farmers awareness and knowledge about their uses and risks by conducting a discourse analysis and community intervention in Metztitlán Hidalgo, Mexico.

Article

Application pesticides Exposition Intoxicated Knowledge risk Toxic MEDICINA Y CIENCIAS DE LA SALUD CIENCIAS MÉDICAS SALUD PÚBLICA

EFECTO DEL ENDOSULFAN SOBRE LA ACTIVIDAD DE GLUTATION S-TRANSFERASA DE OCIMUM BASILICUM L.

MARICELA RAMIREZ SANDOVAL (2013)

Phytoremediation is a strategy to eliminate or reduce the undesirable effects of pollutants in the environment. This technology can be enhanced if the mechanisms by which it occurs are known. Previously in our laboratory, we have found that the plant Ocimum basilicum L. has a phytoremediating effect of endosulfan, a persistent toxic pesticide in the environment. To optimize the phytoremediation of endosulfan by O. basilicum L. we propose to study one of the possible mechanisms involved, the activity of the enzyme Glutathione S-Transferase (GST). It has been described that GST is involved as part of the defense of plants towards exogenous compounds.

La fitorremediación es una estrategia para eliminar o disminuir los efectos indeseables de los contaminantes en el ambiente. Esta tecnología puede potenciarse si se conocen los mecanismos por la que ocurre. Previamente en nuestro laboratorio, hemos encontrado que la planta Ocimum basilicum L. tiene un efecto fitorremediador de endosulfán, un plaguicida tóxico persistente en el ambiente. Para optimizar la fitorremediación de endosulfán por O. basilicum L. nos proponemos estudiar uno de los posibles mecanismos involucrados, la actividad de la enzima Glutatión S-Transferasa (GST). Se ha descrito que GST está involucrada como parte de la defensa de las plantas hacia compuestos exógenos.

Master thesis

Endosulfán Glutatión s-transferasa Ocimum basilicum Fitorremediación Plaguicida tóxico Phytoremediation   Toxic pesticide CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Proteomic analysis of non-toxic Jatropha curcas byproduct cake: fractionation and identification of the major components

ANDRES LEON VILLANUEVA JOSE ANGEL HUERTA OCAMPO ALBERTO BARRERA PACHECO SERGIO MEDINA GODOY ANA PAULINA BARBA DE LA ROSA (2018)

"Jatropha curcas non-toxic genotypes have been reported in Mexico and the press-cake, after oil extraction, represents a potential of new source of protein for food and feed uses. However, the characterization of the press-cake proteins is still unknown. The aim of this work was to carry out the molecular characterization of J. curcas seed storage proteins. Proteins in press-cake were pre-fractionated according to the classical Osborne procedure. Main protein fraction in J. curcas cake was represented by glutelins, the electrophoretic analysis showed that glutelins and globulins have the same profile, indicating that oil extraction process could have effect on globulins agglomeration. Protein fractions were analyzed by two-dimensional gel electrophoresis and mass spectrometry, results provide a new dataset of protein species or proteoforms that are accumulated in J. curcas endosperm. The identification of toxic proteins such as curcin in the non-toxic variety could represent that this protein have important roles in seeds. Regulatory proteins such as proteasome subunits and 14-3-3 were identified. A group of different heat shock and stress defense protein species was detected. Proteases related with inhibitory activity against DPPIV were also detected; this could support the potential use of J. curcas cake as nutraceutical food."

Article

Jatropha curcas LC–MS/MS Mass spectrometry Non-toxic Proteome Seed storage proteins BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA MOLECULAR BIOLOGÍA MOLECULAR

Intoxication and risks derived from exposure to pesticides in farmers Metztitlan Hidalgo, Mexico

Jeiry Toribio Jiménez Jesús Carlos Ruvalcaba Ledezma Sandra Yazmín Cortés Ascencio Francisco Prieto García Nadia Azenet Pelallo Martínez Patricia Vázquez Alvarado (2015)

The aim of the investigation consists on describing the toxic impact of pesticides, as well as analyzing farmers' awareness and knowledge about their uses and risks by conducting a discourse analysis and community intervention in Metztitlán Hidalgo, Mexico. A qualitative intervention study was conducted with a phenomenological-ethno methodological pragmatic design through the analysis of the discourse of 4 people, where three of them had been intoxicated by pesticides, as well as one vendor of these products. In three phases, a contextual tour was performed. Photographs of the agricultural context were taken, especially when the pesticides were being applied; depth interviews were applied, and finally categories were structured in order to conduct the analysis of people speech.

Article

Application pesticides Exposition Intoxicated Knowledge risk Toxic impact CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS AGROQUÍMICA

Statistically coherent calibration of X-ray fluorescence spectrometry for major elements in rocks and minerals

SURENDRA PAL VERMA JAISWAL SANJEET KUMAR VERMA MARIA ABDELALY RIVERA GOMEZ DARIO TORRES SANCHEZ LORENA DIAZ GONZALEZ ALEJANDRA AMEZCUA VALDEZ BEATRIZ ADRIANA RIVERA ESCOTO MAURICIO ROSALES RIVERA ARMSTRONG ALTRIN SAM JOHN SELVAMONY Héctor López Loera FERNANDO VELASCO TAPIA PANDARINATH KAILASA (2018)

"We applied both the ordinary linear regression (OLR) and the new uncertainty weighted linear regression (UWLR) models for the calibration and comparison of a XRF machine through 59 geochemical reference materials (GRMs) and a procedure blank sample. The mean concentration and uncertainty data for the GRMs used for the calibrations (Supplementary Materials) (available here) filewere achieved from an up-to-date compilation of chemical data and their processing from well-known discordancy and significance tests. The drift-corrected XRF intensity and its uncertainty were determined from mostly duplicate pressed powder pellets. The comparison of the OLR (linear correlation coefficient ?0.9523–0.9964 and 0.9771–0.9999, respectively, for before and after matrix correction) and UWLR models (?0.9772–0.9976 and 0.9970–0.9999, respectively) clearly showed that the latter with generally higher values of is preferable for routine calibrations of analytical procedures. Both calibrations were successfully applied to rock matrices, and the results were generally consistent with those obtained in other laboratories although the UWLR model showed mostly narrower confidence limits of the mean (slope and intercept) or lower uncertainties than the OLR. Similar sensitivity (?2.69–46.17?kc·s?1·%?1 for the OLR and ?2.78–59.69?kc·s?1·%?1 for the UWLR) also indicated that the UWLR could advantageously replace the OLR model. Another novel aspect is that the total uncertainty can be reported for individual chemical data. If the analytical instruments were routinely calibrated from the UWLR model, this action would make the science of geochemistry more quantitative than at present."

Article

Weighted least-squares Geochemical reference samples Neutron-activation analysis Fitting straight-lines Trace-elements 1987 compilation Replicated observations Quality-control Regression XRF BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOQUÍMICA BIOQUÍMICA

Spatial prediction of the concentration of selenium (Se) in grain across part of Amhara Region, Ethiopia

Alice Milne Tilahun Amede Elizabeth Bailey Christopher Chagumaira Samuel Gameda Martin Broadley Edward Joy (2020)

Grain and soil were sampled across a large part of Amhara, Ethiopia in a study motivated by prior evidence of selenium (Se) deficiency in the Region's population. The grain samples (teff, Eragrostis tef, and wheat, Triticum aestivum) were analysed for concentration of Se and the soils were analysed for various properties, including Se concentration measured in different extractants. Predictive models for concentration of Se in the respective grains were developed, and the predicted values, along with observed concentrations in the two grains were represented by a multivariate linear mixed model in which selected covariates, derived from remote sensor observations and a digital elevation model, were included as fixed effects. In all modelling steps the selection of predictors was done using false discovery rate control, to avoid over-fitting, and using an ?-investment procedure to maximize the statistical power to detect significant relationships by ordering the tests in a sequence based on scientific understanding of the underlying processes likely to control Se concentration in grain. Cross-validation indicated that uncertainties in the empirical best linear unbiased predictions of the Se concentration in both grains were well-characterized by the prediction error variances obtained from the model. The predictions were displayed as maps, and their uncertainty was characterized by computing the probability that the true concentration of Se in grain would be such that a standard serving would not provide the recommended daily allowance of Se. The spatial variation of grain Se was substantial, concentrations in wheat and teff differed but showed the same broad spatial pattern. Such information could be used to target effective interventions to address Se deficiency, and the general procedure used for mapping could be applied to other micronutrients and crops in similar settings.

Article

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA SELENIUM TRACE ELEMENTS HUNGER ERAGROSTIS TEF WHEAT GEOSTATISTICS

Indoor Pollution Emissions from Building Materials; Case of Study: Gypsum Boards

SILVERIO HERNANDEZ MORENO (2012)

Este reporte presenta una evaluación de las emisiones de materiales de construcción, al interior de los edificios que pueden causar daño a la salud de los usuarios durante la ocupación, pues emiten sustancias tóxicas al interior de los edificios. Este reporte presenta un caso de estudio que evalúa a los tableros de yeso, frecuentemente usados en la construcción de muros divisorios y falsos plafones. La parte experimental se basa en un espacio tridimensional el cual simula un cuarto de cualquier tipo de edificación; por ejemplo: un salón de clases u oficina. Las condiciones ambientales al interior, tales como: ventilación, temperatura y humedad, afectan directamente las emisiones de sustancias químicas por los materiales de construcción. La metodología se basa en la comparación de materiales convencionales y materiales alternativos con distinta composición y similares características, en donde usamos métodos de prueba, condiciones ambientales, instrumentos y herramientas similares. Este es un estudio muy importante para entender los problemas relacionados con la contaminación ambiental, específicamente del aire y sus efectos en el interior de los edificios, y que se relaciona directamente con la salud pública e indirectamente con los sistemas constructivos y la selección de materiales en los edificios. Las pruebas concluyen que los materiales alternativos (de contenido reciclado) son mejores que los tradicionales, porque reducen la contaminación del aire al interior de los edificios.

This report presents an evaluation of emissions from indoor building materials that may cause health damage to the people who occupy the building, since these materials emit toxic chemicals into the air and indoor surfaces. This report presents a case study which evaluates Gypsum Boards, frequently used in the construction of dividing walls and ceilings. The experimental part of this report is based on a three-dimensional space that simulates a common room; for example, a classroom or a workstation. The indoor environmental conditions, such as ventilation, temperature, and humidity, affect chemical emissions from building materials. The technical methodology used, is based on the comparison of conventional materials and alternative materials with similar characteristics and different composition, using similar testing methods, environmental conditions, and instruments and tools. This is a very important report to understand problems related to environmental pollution, specifically of air and its effects indoors, directly on public health, and indirectly on building systems and selection of materials. The tests conclude that alternative materials (with recycled content) are better than traditional ones, because they reduce indoor pollution.

Article

INGENIERÍA Y TECNOLOGÍA Contaminación del aire Emisiones interiores Sustancias tóxicas Tableros de yeso Materiales de construcción Air pollution Indoor emissions Toxic chemicals Gypsum boards Building materials