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Introduction: Water pollution is one of the main environmental problems affecting Cuba. The galvanic and leather tanning industries in the same country generate wastewater contaminated with chromium which can be treated using constructed wetlands. Objective: To evaluate chromium removal behavior in experimental subsurface wetlands. Materials and Methods: Two experimental systems consisting of horizontal subsurface flow wetlands were constructed: one planted with Cyperus Alternifolius and the other with two varieties of Heliconia (Rostrata and Wagneriana), using red ferrallitic soil as substrate. The Atomic Absorption Spectrometry method was used for the determination of total chromium and Excel of the Office package in its version 16.0.17726 was the software adopted for statistical processing. Results and Discussion: The Cyperus Alternifolius was the species that showed the best assimilation, managing to transport the metal to the leaves. The kinetics of chromium removal in the wetland and in the soil used as substrate were evaluated, demonstrating the importance of plants and associated microorganisms in the retention of the metal, with higher retention in the wetland. Chromium removal efficiencies of over 98% were obtained. Conclusions: Using the Cyperus Alternifolius plant together with the red ferrallitic soil, and performing the corresponding scaling with the kinetic constants obtained, it is possible to construct a treatment system that efficiently removes chromium from wastewater associated with the galvanic industry and tanneries. [ABSTRACT FROM AUTHOR]

In this work, Titania was modified by sulfation or fluorination and platinum on the surface to improve the Cr (VI) reduction efficiency compared to the bare T iO2 material synthesized by the sol-gel method. The synthesized materials were characterized by XRD, SBET, UV-Vis DRS, XRF, TEM, FTIR, and XPS. The modifications led to higher stability in the Anatase phase and surface area of this semiconductor. The addition of F and Pt in T iO2 led to absorption increases in the visible region of the electromagnetic spectrum. A correlation between the new physicochemical properties obtained after T iO2 modification and the photocatalytic performance of this material was observed. The best result in chromium reduction was obtained using Pt-S-T iO2 as the photocatalyst; this material showed a suitable combination of surface area, high UV-Vis absorption, high hydroxylation, and the existence of Pt nanoparticles on the surface, which favors an increased electron-hole pair half-life. Different reaction parameters were also evaluated, which demonstrated that the best photocatalytic performance was obtained under an N2 atmosphere, a light intensity of 120 W/m2 , and 2 hours of total reaction time. Likewise, it was noted that an increase in reaction time from 2 to 5 hours, had a detrimental effect on reducing Cr (VI) efficiency. [ABSTRACT FROM AUTHOR]

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Tannins are phenolic compounds of great economic and ecological interest, with various uses among which are natural tanning of skins, which help to minimize the environmental impact caused by the indiscriminate use of chromium. For this reason, in this research, it was proposed to extract, quantify and evaluate tanning effect of tannins on the skin of fish of the species cachama (Colossoma macropomum), extracted from the sap of the pseudostem of banana (Musa paradisiaca) in a state of senescence. For this, extractions were made with different concentrations of solvent Sap/Ethanol/Water varying its temperature (4 and 30 °C) with the purpose of finding the best ratio of solvents to optimize extraction of tannins. It was found that the optimal tannins extraction temperature of the pseudostem was at 4 °C with a ratio 1:1 Sap/Ethanol. The extract obtained was analyzed by a qualitative test to show the presence of condensed tannins in the pseudostem in a state of senescence. The quantification of tannins was performed by UV-Vis spectrophotometry analysis using Folin Ciocalteu method at a measurement of 280 nm, obtaining a maximum concentration of 12,27 g/L equivalent to gallic acid (EAG). The process of tanning in cachama fish skin (Colossoma macropomum) was performed, where physical-mechanical properties of the leather obtained were determined as tensile strength (26,3 MPa), elongation percentage (91,2 %), tear resistance (58,6 N), shrinkage temperature (62 °C), distension (13,72 mm) and breakage (53,16 daN), comparing the quality of tanning with vegetable tannin extracts of the pseudostem with industrial tanning with chromium (wet blue). It was found that the pseudostem extract can be a potential substitute to chromium salts, allowing tannery processes with similar properties and with less environmental impact. [ABSTRACT FROM AUTHOR]

Introduction. The versatile metabolism of microorganisms allows biodegradation of a wide variety of contaminants; however, the increasing scale of the industry exceeds its po- llutant processing capacity. Due to its high toxicity, hexavalent chromium Cr(VI) is one of the heavy metals with the greatest global dissemination and concern. There are numerous investigations focused on proposing treatments to purify the different ecosystems affected with this metal; however, knowledge about various microorganisms from the same source that could help solve this problem is restricted. Objective. To evaluate the efficiency in the reduction of Cr(VI) of bacterial consortia (B. thuringiensis, B. amyloliquefaciens and Paenibacillus sp.) in a Batch type treatment, using municipal wastewater from Río Pasto as a substrate. Methodology. A mathematical model was formulated that reliably predicted the behavior of the consortia, in relation to their growth and reduction percentage, the results of the simulations were compared with experimental data to select the consortium with the best Cr(VI) reduction results). Subsequently, its efficiency in the reduction of Cr(VI) was determined, using unsterilized residual river water as a substrate. Results. The statistical analyzes highlighted the absence of statistically significant differences in the reduction percentages between the consortia. However, with the selected culture, a reduc- tion percentage of 91% was presented in 156 hours. Conclusion. The results found in this research are promising for their application in the improvement of treatment practices for Cr(VI) bioremediation. [ABSTRACT FROM AUTHOR]

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El presente artículo se centró en describir los procesos típicos, materiales utilizados, principales riesgos para la salud derivados de la industria del curtido de pieles, así como el impacto ambiental asociado a dicha industria y actividad en la provincia de Tungurahua, Ecuador. Para el desarrollo del presente documento se realizó una revisión integradora de la literatura, como una modalidad de investigación bibliográfica. Como resultado principal se obtuvo que la contaminación de los afluentes hídricos, con químicos provenientes de las aguas residuales, producto de la transformación de las pieles animales en cuero para la industria de la marroquinería, ha determinado el crecimiento exponencial de la contaminación, debido a la deficiente gestión que se otorga a dichos residuos. La contaminación de los recursos hídricos se evidencia en la cantidad de cromo vertido en el agua, tanto de tipo trivalente, como hexavalente. La concentración de Cr6 va desde los 52.3 a los 392.9 mg/L, rebasando el límite que determina la normativa TULAS. Se concluye que la determinación de Cr6 se convierte en un potencial factor y un riesgo inminente para el desarrollo de las diferentes afectaciones asociadas a la exposición al cromo.

Introduction: The Codex Alimentarius proposes limiting the maximum levels for lead and cadmium in animal products. In the European Union there is legislation that sets maximum values for heavy metals (arsenic, cadmium, copper, chromium and lead) in animal feed. Objective: The purpose of this work is to determine heavy metals (arsenic, cadmium, chromium, copper, and lead) in muscle, liver and kidney of pigs slaughtered in the municipal slaughterhouse of Guadalajara. Methods: After sacrifice, 25 animals were randomly selected. Three types of tissues were obtained from each of the pigs (muscle, liver, and kidney) to constitute a set of 75 samples. Once the digestion was carried out, the metals were quantified by flame (arsenic, cadmium, copper, chromium, and lead) in an Atomic Absorption Spectrophotometer. The detection limits of metals in the digestion were: arsenic=0.12 ppm, cadmium=0.0028 ppm, chromium=0.0054 ppm, copper=0.0045 ppm, and lead=0.013 ppm. One-way analysis of variance (ANOVA) was used to analyze the data. Results and Discussion: For arsenic, cadmium and lead, the permissible levels in the study tissues, none exceeded the maximum levels reported in the modification to the official Mexican standard, NOM-004-ZOO-1994. The liver samples presented an average of 43,824 mg/L. Of the kidney samples analyzed, they offered minimum concentration values of 1.8437 mg/L and 5.7205 mg/L as a maximum value, presenting an average of 0.9568 ppm. In the present study, the highest concentrations of copper were in the liver, similar to what was reported in another study. With respect to chromium values, the maximum residue levels are not established by the official Standard and for that reason it is not possible to make a comparison of the values found in this study. Conclusion: Only 1.33% presented levels higher than the permitted limits of copper, so for the most part the samples met the acceptance levels according to the Official Mexican Standard NOM-004-ZOO. [ABSTRACT FROM AUTHOR]

Copyright of Revista ION is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of the research was to evaluate the potential of refractory chromites from Victoria I deposit (in Camagüey, Cuba) as a source of chromium for producing electrodes to recharge parts by manual electric arc welding. A mixture of rutile, graphite, refractory chromite, sodium silicate and AISI 1009 steel rods was used as raw material. The experimental electrodes were obtained by pressing the coating from a dosed mixture with the previous components. The mass balance predicts the weld bead can be alloyed with carbon and chromium by introducing refractory chromite and graphite in the rutile coating. The experimental results corroborated that the welding process allowed obtaining 2.3% carbon and 2.89% chromium in the metal deposited by the experimental electrodes. Results show that refractory chromites from Camagüey constitute a potential source of chromium for manufacturing rutile-coated electrodes for recharging parts by manual electric arc welding.

En los últimos años los residuos generados por las industrias metalúrgicas han recibido mayor atención a causa de las implicaciones ambientales que conlleva su disposición, no obstante, se ha reportado que este tipo de residuos funcionan como adsorbentes de bajo costo para remover metales pesados de aguas residuales debido a su composición. Por otro lado, existen procesos que se llevan a cabo en las industrias de recubrimientos metálicos que generan aguas residuales con altos contenidos de cromo hexavalente, el cual es sumamente tóxico para la salud y el medio ambiente. En el presente trabajo se realizaron una serie de pruebas de adsorción en una solución sintética de cromo hexavalente empleando como adsorbentes residuos procedentes de la industria minero-metalúrgica. Se observó que, empleando un residuo constituido principalmente por hematita y magnetita, se logró remover el 76% del cromo presente en la solución.

Copyright of Revista Eletrônica em Gestão, Educação e Tecnologia Ambiental is the property of Revista Eletronica em Gestao, Educacao e Tecnologia Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

El efluente del proceso del curtido genera impactos negativos en la salud y el ambiente debido a que en esta etapa solo se aprovecha el 70% del cromo (Cr) total utilizado; por lo cual la bioadsorción surge como una alternativa en la remoción de metales pesados. En tal sentido, el objetivo de la presente investigación fue evaluar la capacidad de remoción de cromo en efluentes de curtiembre utilizando un consorcio de levaduras constituido por cepas de Saccharomyces cerevisiae (S) y Pichia guilliermondi (P) aislados de residuos agroindustriales. El diseño experimental consistió en 4 biorreactores de 250 ml condicionados con muestras de efluente de la etapa de curtido, teniendo como sorbente el consorcio (S+P), controlados a 0, 6, 12 y 24 horas. Las muestras fueron analizadas por la técnica de espectrofotometría de absorción atómica a la flama. Los resultados muestran una capacidad de remoción de Cr total de 57% y 54% en concentración de 50 y 100 ppm respectivamente por el consorcio de levaduras; asimismo, la evaluación estadística con ANOVA permite afirmar que no existe diferencia significativa (p>0.05) al emplear ambas concentraciones, recomendándose el uso de la más alta en el proceso de bioadsorción de efluentes de curtiembres.

O cromo (Cr3+) é necessário na dieta humana, principalmente para o metabolismo dos carboidratos. Pode ser encontrado em água potável, levedo de cerveja e grãos integrais, ou através de gelatinas contaminadas, proveniente da extração do colágeno no tratamento industrial do couro bovino, podendo causar danos à saúde quando ingerido acima de 200µg/dia. O objetivo deste trabalho foi investigar a presença de Cr3+ em gelatinas comerciais de acordo com a legislação vigente. A metodologia utilizada foi espectrofotometria de absorção atômica (EAA) após a digestão de oito amostras de gelatina, em triplicata (marcas do tipo colorida em pó, incolor em pó e em folha incolor). Os resultados obtidos demonstraram que todas as amostras de gelatina apresentaram concentrações de Cr+3 acima do permitido pela legislação (0,1 ppm). Concluímos que o Cr+3 pode ter sido arrastado durante o processamento do colágeno para a fabricação de gelatina e/ou adicionado ao produto colorido como corante.

Se elaboró el proyecto de explotación del yacimiento de cromo Rosita que permitirá suministrar parte del mineral para el aumento de la economía del país y de la provincia de Camagüey. La metodología utilizada partió de un estudio del yacimiento, teniendo en cuenta las características hidrogeológicas, la tectónica, morfología y propiedades físico–mecánicas del mineral, así como las reservas con las que cuenta el yacimiento. Se realizó la selección del equipamiento minero, el cálculo de la productividad así como de los parámetros de explotación. Se hizo el cálculo de los trabajos de perforación y voladura, la organización del plan calendario para su explotación y la valoración económica de las actividades fundamentales; el análisis del impacto medioambiental, el cumplimiento de las medidas de seguridad y salud en el trabajo para la protección del personal. Se elabora el proyecto de explotación que permitirá extraer de forma racional y eficiente las reservas de cromo, considerando las características del equipamiento disponible

El botadero de basura a cielo abierto de la ciudad de Portoviejo se encuentra en etapa de cierre técnico y en este existen desechos de origen doméstico e industrial. Estos desechos pueden generar contaminación por los diversos elementos químicos tóxicos que contienen. El objetivo de este trabajo fue caracterizar los suelos mediante parámetros físicos y químicos como pH, humedad, conductividad eléctrica, Residuo Seco Evaporado (RSE), Residuo Seco Calcinado (RSC), densidad real y aparente y medir Cr (VI), Ni, Br y Fe para proponer una zonificación de posible propagación de los contaminantes, con relación a las curvas de lixiviación. Se procedió a analizar varias técnicas de muestreo, en cuanto a factibilidad y aplicabilidad a la zona de estudio, por ello se empleó metodología propuesta por la Norma Técnica Ambiental Ecuatoriana, la Secretaría de Medio Ambiente de México y la propuesta basada en la publicación de Investigación de la Contaminación de Suelos del Gobierno Vasco de España, se optó por utilizar esta última, que dio como resultado un total de 20 muestras en la zona de estudio. La caracterización fisicoquímica del suelo permitió obtener información de sus propiedades, las mismas que sirvieron como insumo para la elaboración de mapas de distribución espacial, con la finalidad de aplicar algebra de mapas, en función de la variación de estas propiedades, para la determinación de dos zonas, donde, se identificó mayor y menor vulnerabilidad de contaminación en cuanto a la movilidad de estos elementos. Los valores mostrados por el pH y conductividad eléctrica determinaron que son suelos que se comportan de manera neutral y ligeramente alcalino, y suelos significativamente salinos. El porcentaje de humedad obtenido en cada uno de los extractos determinó suelos franco arenosos. Como resultado se tuvo que la mayor concentración de los elementos medidos está orientada al suroccidente del botadero, y tras analizar la relación entre la zonificación y lixiviación, se pudo determinar cómo se encuentra la movilidad de estos elementos, donde se debe prestar especial atención a la zona vulnerable que presenta curvas de lixiviación crecientes.

O cromo é um mineral-traço essencial absorvido da alimentação, principalmente alguns alimentos como carnes e oleaginosas, sendo armazenado principalmente no fígado tendo como função primária um aumento na tolerância à glicose associado à insulina no metabolismo celular. O objetivo desse trabalho foi de averiguar os efeitos do cromo em sua versão Picolinato sobre a glicemia e como que ele manipula a concentração de glicose plasmática no organismo durante o exercício. Para tanto foram utilizados 17 indivíduos saudáveis fisicamente ativos que participaram de todas as fases do experimento o qual foi dividido em quatro fases distintas, grupo suplementado com 50g de maltodextrina em repouso (Malt), grupo suplementado com 50g de maltodextrina em exercício aeróbio (MEx), grupo suplementado com 50g de maltodextrina e mais 70 mcg de Picolinato de Cromo em repouso (MCro) e grupo suplementado com 50g de maltodextrina e mais 70 mcg de Picolinato de Cromo em exercício aeróbio (MCroEx). A glicemia plasmática foi monitorada a cada 15 minutos durante 75 minutos com o uso de um glicosímetro. O cromo gerou efeito positivo na captação de glicose, baixando significativamente os níveis plasmáticos, o que corrobora com alguns estudos, porém realizados com animais. ABSTRACT Effects of the supplementation of chromium picolinate about the concentration of plasma glycemia during physical and rest exercise Chromium is an essential trace mineral absorbed from food, especially some foods such as meat and oil, and is mainly stored in the liver as the primary function having an increase in glucose tolerance associated with insulin in cell metabolism. The aim of this study was to investigate the effects of chromium picolinate in its version on blood glucose and how he handles the plasma glucose concentration in the body during exercise. Therefore, we used 17 healthy physically active individuals who participated in all phases of the experiment which was divided into four distinct phases, group supplemented with 50g of maltodextrin at rest (Malt), supplemented group with maltodextrin 50g in aerobic exercise (MEx), group supplemented with 50g of maltodextrin and 70 mcg of Chromium Picolinate at rest (MCro) and group supplemented with 50g of maltodextrin and 70 mcg of Chromium Picolinate in aerobic exercise (MCroEx). The plasma glucose was monitored every 15 minutes for 75 minutes using a glucometer. Chromium had a positive effect on glucose uptake, significantly lowering plasma levels, which corroborates some studies, though conducted on animals.

Debido a su alta toxicidad, el cromo debe eliminarse de las aguas residuales industriales que lo contienen antes de descargarlas en los cuerpos acuíferos. Utilizando técnicas discontinuas (en lote) de remediación con la biomasa aquenio de plátano hispánico es posible la eliminación del contaminante a escala de laboratorio. El método es de muy bajo impacto ambiental y económico. Se determinó el mecanismo de retención de Cr(VI) y Cr(III) para su aplicabilidad a nivel industrial. La concentración de Cr(VI) y Cr(III) se determinó por espectrofotometría UV-Vis con 1,5-difenilcarbazida (DFC) a 540 nm. Las especies de cromo unidas a la superficie del biomaterial se analizaron por resonancia paramagnética electrónica (RPE). Los resultados evidenciaron la presencia de especies intermediarias de Cr(V) unidas a la superficie del material. También se demostró que las especies finales sobre la superficie del sorbente contienen cromo trivalente.

The effect of inoculation with endotrophic micromycete Cylindrocarpon magnusianum on the formation of adaptive physiological and biochemical reactions in test tomato plants under the action of heavy metal salts has been studied. The experimental design included plant inoculation with a fungus culture (control population) and these fungus populations were preliminarily grown on a pentose-dextrose agar medium with the addition of heavy metal salts in different concentrations. The inoculated plants were grown on substrates without the addition of heavy metal salts (control) and with the addition of zinc, copper, lead, and chromium salts in different concentrations similar to additions in agar when growing fungus populations. In experimental plants, we determined the content of photosynthetic pigments and ascorbic acid in the leaves (spectrophotometry), nitrates in the leaves (ionometric analysis), the aerial part and root system biomass by the gravimetric method, and the degree of fungal infection development of plants via the light microscopy method of macerated and colored fragments of the plant root system. No stimulatory effect, increasing the resistance of plants to the action of heavy metal salts when plants were inoculated with a control population of the C. magnusianum fungus, was revealed. A positive effect was revealed during the inoculation of plants with fungal populations, previously adapted to the action of salts of chemical elements, especially chromium and lead salts, and during further plants' cultivation on substrates with the introduction of these non-biogenic chemical elements hazardous to the life of plants. The effect is associated with the stability of the pigment system, the redistribution of plant biomass, and the synthesis of the antioxidant-ascorbic acid in the leaves. Intensive development of fungal infection in plant roots was also noted. The study results indicate the most effective partnership between the C. magnusianum fungus and the plant root system under stressful conditions for plant life. [ABSTRACT FROM AUTHOR]

The objective of the research was to evaluate the potential of refractory chromites from Victoria I deposit (in Camagüey, Cuba) as a source of chromium for producing electrodes to recharge parts by manual electric arc welding. A mixture of rutile, graphite, refractory chromite, sodium silicate and AISI 1009 steel rods was used as raw material. The experimental electrodes were obtained by pressing the coating from a dosed mixture with the previous components. The mass balance predicts the weld bead can be alloyed with carbon and chromium by introducing refractory chromite and graphite in the rutile coating. The experimental results corroborated that the welding process allowed obtaining 2.3% carbon and 2.89% chromium in the metal deposited by the experimental electrodes. Results show that refractory chromites from Camagüey constitute a potential source of chromium for manufacturing rutile-coated electrodes for recharging parts by manual electric arc welding. [ABSTRACT FROM AUTHOR]

Introducción. El río Bogotá es uno de los más contaminados del mundo; esto es debido, en gran medida, al vertimiento directo de aguas residuales domésticas e industriales sin ningún tratamiento a lo largo de los municipios que atraviesa, incluido Bogotá D.C. Objetivo. Determinar el efecto de las actividades antrópicas del municipio de Villapinzón, Colombia, sobre las características fisicoquímicas y microbiológicas del río Bogotá. Materiales y métodos. Se midieron 26 variables fisicoquímicas y 4 microbiológicas en nueve estaciones de la parte alta del río Bogotá. Las variables químicas incluyeron cromo, plomo y mercurio y las microbiológicas Escherichia Coli, coliformes totales, Enterococcus faecalis y Pseudomona aeruginosa. Resultados. En todas las estaciones las variables microbiológicas presentan valores por encima del nivel saludable. La concentración de cromo total en la zona de influencia de las curtiembres supera el nivel máximo que tiene efecto adverso sobre la salud humana. Conclusiones. Se encontró un deterioro progresivo de la calidad del agua del río Bogotá, lo cual es ocasionado por las actividades antrópicas que se realizan en Villapinzón; es posible que esta sea la causa de la alta prevalencia de enfermedades infecciosas y parasitarias del sistema digestivo en niños menores de 5 años del municipio.

ABSTRACT BACKGROUND Patients that underwent Percutaneous Endoscopic Gastrostomy (PEG) present with protein-energy malnutrition. Trace elements are required in small quantities and Chromium (Cr) displays a major role in the metabolism. OBJECTIVE This study aims to evaluate Cr levels and its relationship with serum proteins, BMI and underlying diseases during the first 3 months of PEG feeding. METHODS Prospective observational study during 3-months, when PEG was performed (T0), after 4 (T1), and 12 weeks (T3). Initial evaluation included: age, gender, underlying disease, NRS-2002, BMI, serum albumin, transferrin and Cr concentration. At T1 and T3 a blood sample was collected for Cr, albumin and transferrin. A Graphite Furnace Atomic Absorption Spectroscopy was used to assess Cr. According with the underlying disease, patients were divided into two groups: head and neck cancer (HNC) and neurological dysphagia (ND). All patients were fed with homemade meals. RESULTS A one hundred and twenty-nine patients (80 males), 26-95 years old were studied: HNC-52; ND-77. The observed data included low mean values of BMI from 71 patients; low Cr-8, low albumin-70, low transferrin-85 and 57 with both proteins low. Albumin was associated with survival time ( P =0.024) and there was a significant correlation between albumin and Cr (r=0.217, P =0.012). A good evolution of Cr and proteins values was observed, with no low Cr levels at T3. CONCLUSION Low serum Cr is rare in PEG-patients, with no relationship to other studied parameters. For the minority of patients displaying low Cr before gastrostomy, homemade PEG meals seem to be effective.

Los cerdos Pelón Mexicano (CPM) y Cuino Mexicano (CCM) son nativos de México. El cromo (Cr) es un nutriente esencial en el metabolismo de carbohidratos, lípidos y aminoácidos, pero su efecto en cerdos a nivel de la fermentación cecal se desconoce. El objetivo fue evaluar la fermentación cecal in vitro y el nitrógeno (N) digestible en el intestino del CPM y CCM, mediante la adición de Cr en la dieta. Se sacricaron 48 cerdas con peso vivo de 104±0.5 kg, 24 por cada genotipo, de las cuales se colectó contenido cecal e ileal. Las muestras de contenido ileal se incubaron in vitro y se evalúo la fermentación (ml gas g−1 MS) a las 3, 6, 9, 12, 24 y 36 h y la composición química. El diseño experimental fue completamente al azar con arreglo factorial 2 x 2. No hubo diferencias entre genotipos (P>0.1), la dieta sin Cr mostró mayor fermentación (p < 0.001), la producción de gas acumulada (ml gas g−1 MS) no mostro diferencias (P>0.1) por efecto del genotipo o dieta. Hubo mayor contenido de N total y N-NH3 en íleon para el genotipo CCM (p < 0.05). No hubo diferencia (P>0.05) en el contenido de N-total, N-NH3 y N aminoacidico a nivel cecal. Se concluye que los CCM mostraron un mayor contenido de N-Total y N-NH3 en íleon que los CPM; el Cr dietario no inuyó en el contenido de nitrógeno en intestinos delgado y grueso, ni en la fermentación cecal microbiana de los cerdos.

La curtición mineral (cromo III) es la más utilizada a nivel mundial, produce efectos nocivos al ambiente no solo en el proceso, sino también cuando los artículos han cumplido su vida útil y deben ser desechados a los vertederos de basura. En ese lugar, el contacto con agentes oxidantes puede producir la degradación del cromo trivalente a hexavalente, el cual es un compuesto altamente contaminante. El presente estudio tiene por finalidad determinar el efecto de una curtición con Caelsalpinia spinosa (tara) en combinación con oxazolidina, para crear una curtición agradable con el ambiente al reemplazar al cromo III. Como conclusión se determina que, con la utilización de oxazolidina más Caelsalpinia spinosa, se consiguen cueros con resistencias físicas elevadas que superan los estándares de calidad de las normas técnicas, así como una apreciación sensorial muy atractiva para el juez tanto en los cueros como en los artículos de marroquinería.

Copyright of Agro Productividad is the property of Colegio de Postgraduados and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study reviews the progress of recent years in the use of organic chromium products in poultry feed and production. Important topics such as the functions of this mineral element, the most used types of products, their supplementation levels, as well as the effects of the inclusion of this microelement in the diets through different forms, in the productive performance of animals, mitigation of caloric stress and other indicators of interest were analyzed. The most promising, according to the obtained effects, are chromium picolinate and chromium linked to yeast, and the respective responses of animals to their supplementation have been the main focus of research in recent years. [ABSTRACT FROM AUTHOR]

The chromium (Cr+3) is necessary in the human diet, mainly for the metabolism of carbohydrates. It can be found in drinking water, beer yeast and whole grains or through contaminated gelatins, derived from the extraction of collagen in the industrial treatment of bovine leather, and can cause damage to health when ingested above 200 µg/day. The objective of this work was to investigate the presence of Cr+3 in commercial gelatins in accordance with current legislation. The methodology used was analyses by Atomic Absorption Spectrophotometry (AAS) after the digestion of eight gelatin samples in triplicate (colored powder type, colorless powder and colorless leaf). The results obtained showed that all gelatin samples presented concentrations of Cr+3 above that allowed by legislation (0.1 ppm). We conclude that Cr+3 may have been entrained during the processing of collagen for the fabrication of gelatin and/or added to the colorful product as a colorant. [ABSTRACT FROM AUTHOR]

Antecedentes: los taninos son sustancias orgánicas que reaccionan con las proteínas del colágeno de las pieles de animales uniéndolas entre sí, aportando gran resistencia a la piel. Bajo esta premisa, estos metabolitos polifenólicos son una alternativa potencial para la industria de las curtiembres, siendo utilizadas en los procesos de transformación de las pieles a cueros. Objetivo: extraer y cuantificar los taninos vegetales presentes en la semilla del mango criollo (Mangifera indica) para su potencial aplicación como curtiente en la piel ovina de la raza Santa Inés (Ovis aries). Métodos: para ello, se realizó la extracción de los taninos vegetales comparando la mejor concentración disolvente etanol - agua entre 70:30 y 50:50. Se cuantificó la concentración de taninos mediante el análisis de espectrofotometría UV - VIS, método Folin Ciocalteu. Se evaluó la capacidad de curtición en la piel ovina mediante las propiedades físicas del cuero, ruptura de la flor, resistencia al desgarre, tensión y elongación. Resultados: los resultados de cuantificación de compuestos fenólicos expresados en ácido tánico permitieron observar que la mayor concentración en la almendra del mango es la solución etanol - agua 50/50 con 114,77 ppm. Los cueros ovinos curtidos por los extractos vegetales superaron las pruebas de resistencia a la tracción 12,7 MPa para la concentración de etanol - agua (50 % - 50 %) y 11,3 MPa para la concentración de etanol - agua (70 % - 30 %), esto conforme a las Normas Oficiales de la Unión Internacional de Asociaciones de Químicos del Cuero IUP (pruebas de encogimiento, ruptura de la flor, resistencia al desgarre, tensión y elongación). Conclusiones: con base en lo anterior, se estima que la almendra de mango (Mangifera indica) puede ser una alternativa de aprovechamiento para la extracción de taninos y así utilizarlos en el curtido ecológico de pieles cambiando la curtición con cromo. [ABSTRACT FROM AUTHOR]

El curtido de pieles es un proceso reconocido por el vertimiento de desechos químicos y orgánicos, así como por la liberación de compuestos volátiles de olores desagradables y desechos sólidos, que contaminan el agua, el aire y el suelo, produciendo efectos negativos en el ambiente natural y en la salud de la población. Considerando que este comportamiento está influenciado por componentes interrelacionados, el propósito de esta investigación fue identificar los principales factores socioeconómicos y ambientales que caracterizan la actividad curtidora en el municipio de El Cerrito, Valle del Cauca. Mediante el empleo de métodos cuantitativos y cualitativos, que incluyeron entrevistas con actores sociales clave, revisión bibliográfica y trabajo de campo, se pudo establecer que de 13 curtiembres activas, una de ellas corresponde a mediana empresa y las 12 restantes a microempresas (McEs), con cerca de 272 empleados directos. Dichas empresas han diversificado su actividad, dedicándose al curtido de pieles y al alquiler de servicios a curtidores informales. Las McEs presentan una baja capacidad de inversión en maquinaria y en equipos, en modernización tecnológica y en la adopción de programas e infraestructura de mejoramiento ambiental. Se evidenció la falta de conciencia ambiental, de planes de capacitación, de acompañamiento técnico y de políticas gubernamentales que promuevan su desarrollo y la adopción efectiva de programas de control y de prevención de la contaminación. Las características de este sector industrial hacen necesaria la implementación de programas integrales y adaptables a las McEs, de tal manera que conduzcan a mejorar su competitividad y sostenibilidad.

Um dos suplementos dietéticos que vem ganhando maior notoriedade é o mineral cromo, que a literatura afirma como principais funções potencializar a ação da insulina com uma melhor ligação a proteína hepática glut4 captando mais glicose e reduzir o perfil lipídico inibindo a enzima hepática hidroximetilglutaril-CoA-redutase. Com isso, acaba havendo um possível resultado hipoglicemiante e hipolipemiante. Sua utilidade voltada a esportistas não se recorre somente à reposição orgânica, mas porque o cromo pode principalmente favorecer a via anabólica com um aumento da sensibilidade à insulina, que beneficia a resposta metabólica adaptativa com maior captação de aminoácidos e consequentemente a síntese proteica. Dessa forma, parece cabível uma revisão para elucidar a ação do cromo sobre indivíduos submetidos a testes e treinamentos físicos. ABSTRACT Chromium supplementation associated with exercise: a systematic review One of the dietary supplements that has gained most notoriety is the mineral chromium, the literature states main functions potentiate the action of insulin with a better connection liver protein GLUT4 capturing more glucose and reduce the lipid profile inhibiting hydroxymethylglutaryl-CoA liver enzyme reductase. Thus, there is just one possible outcome hypoglycemic and lipid-lowering. Its usefulness oriented to sports uses not only the organic replacement, but mainly because the chromium may further the anabolic via an increase in insulin sensitivity, which benefits the adaptive metabolic response with increased amino acid uptake and protein synthesis accordingly. Thus, it seems appropriate review to elucidate the chromium action on individuals undergoing physical tests and training.

El cromo es un metal pesado ampliamente usado a nivel industrial y vertido comúnmente de manera directa a fuentes hídricas, lo que conlleva a un deterioro de las mismas. Por lo tanto, esta investigación busca comprobar la remoción de cromo ejercida mediante tratamiento físico, químico y biológico en aguas residuales industriales, con el fin de determinar cuál alternativa resulta más sostenible. Para ello se implementaron a escala laboratorio ocho reactores con agua residual industrial de una empresa del sector metalmecánico; inicialmente se evaluó la remoción de cromo mediante sedimentación primaria logrando remociones del 16%; posteriormente, se verificó el efecto llevado a cabo mediante precipitación química con sulfato de aluminio y oxido de calcio; por último, se evaluó la capacidad de biosorción de la microalga Spirulina sp utilizando biomasa viva y muerta a las 24 y 96 horas. Encontrando que existen mecanismos de fácil implementación para evitar vertimientos directos, además se encontró que el tratamiento químico logra disminuir el cromo a valores inferiores de 0.1 mg/l, con remociones del 99%, sin embargo, genera más del 30% de lodos y no favorece la separación del metal. Con el uso de biomasa se alcanzaron remociones de hasta el 96.5% en las primeras 24 horas y un valor final de cromo de 1.02 mg/l, presentando la ventaja que este método genera menos del 10% de lodos y permite recuperar el cromo para su posterior uso. De modo que, se recomienda la implementación de un tratamiento físico-biológico, puesto que mejora la sostenibilidad del proceso.

Las aguas residuales de curtiembres conllevan un problema ambiental y de salud, debido a las altas concentraciones de contaminantes como el cromo, sulfuros, entre otros. Una forma de realizar el tratamiento de estas aguas es por medio del uso de microorganismos tales como las microalgas, debido a su capacidad de utilizar los compuestos inorgánicos y acumular metales y otras sustancias contaminantes. Esta capacidad podría verse magnificada con la inmovilización celular en diferentes matrices. En este artículo se presenta una evaluación de la capacidad de crecimiento y de remoción de nitrógeno, fósforo y cromo por parte de la microalga Scenedesmus sp., comparando la eficiencia entre las células libres e inmovilizadas en una matriz de esponja de Luffa. De esta manera, se obtuvo un mayor crecimiento en las células libres en comparación a las inmovilizadas, aunque sin diferencias significativas entre ambos experimentos. En ambos casos se observaron remociones superiores al 90% para NO–3 , NH+4, PO34 y cromo total, así como una reducción importante de la DBO y DQO (> 97 %) que puede deberse a efecto sinérgico con las bacterias presentes en los cultivos de la microalga. Finalmente, los porcentajes de lípidos en ambos casos fueron superiores al 20% indicando que esta biomasa podría presentar un alto potencial como materia prima para la generación de biodiesel.

Las sales de cromo son reactivos químicos muy utilizados en la industria de curtiembre porque son eficientes para curtir la piel animal, sin embargo, estas sales no se fijan totalmente, por lo que, sus remanentes van a parar a los efluentes, impactando gravemente al medioambiente. El objetivo de este estudio fue remover el cromo (VI) y cromo total de un efluente de curtiembre utilizando electrodiálisis, para ello, se caracterizó una muestra de un efluente de una planta piloto de curtiembre y se preparó una solución sintética en base a ésta, utilizando una sal de cromo para curtiembres de grado industrial, luego, se determinó la corriente límite y se realizó pruebas de electrodiálisis con el 80, 100 y 120% de la corriente límite. Los resultados demostraron que el mayor porcentaje de extracción y el menor consumo de energía eléctrica fue al 80% de la corriente límite.

A participação dos metais pesados nas reações químicas do metabolismo dos peixes tornou esses elementos um dos principais focos nos estudos de contaminação. O objetivo deste estudo foi determinar as concentrações dos metais Cd, Cr, Cu, Pb, Zn e Hg no tecido muscular de peixes da bacia do rio Cassiporé (Estado do Amapá) e ambiente, visando avaliar os riscos de contaminação. As concentrações de Cd em Plagioscion squamosissimus (1,061 µg g-1) e Pb em Poptella compressa (4,280 µg g-1) apresentaram valores que ultrapassam os limites estabelecidos pela legislação brasileira. As concentrações de Cr em P. compressa (0,937 ± 0,5 µg g-1), Pimelodella cristata (0,463 ± 0,03 µg g-1) e Cyphocharax gouldingi (0,364 ± 0,12 µg g-1), bem como de Hg em P. squamosissimus (0,670 µg g-1), Pseudoplatystoma fasciatum (0,630 µg g-1), Hoplias malabaricus (0,570 µg g-1 e Serrasalmus rhombeus (0,548 µg g-1) foram acima do limite legal. A coluna d'água apresentou altas concentrações de metais pesados em todos os pontos analisados, mostrando uma contaminação dessa bacia. Portanto, essas elevadas concentrações de metais pesados no ambiente e tecido muscular dos peixes indicam um elevado grau de contaminação na bacia do rio Cassiporé e risco a saúde do homem.

Organic yeast minerals have higher bioavailability than inorganic sources, which are conventionally used as a supplement for cattle grazing tropical grasses. The objective of this study was to evaluate the influence of mineral-yeast mixture supplementation (chromium, selenium and zinc) on growth performance and digestion in beef steers grazing star grass (Cynodon plectostachius) pastures. For 120 d, daily doses of 0, 15 and 30 g of mineral-yeast mixture into a 1 kg supplement (as fed) were randomly assigned to 30 Brahman×Brown Swiss steers (325±11 kg initial body weight; BW) grazing star grass. The experimental design was completely randomized with three treatments and 10 experimental units (steers). Final BW, total gain, average daily gain and total feed intake increased linearly, as the amount of mineral-yeast mixture increased. Feed conversion was not affected by the mineral-yeast supplementation. Dry matter digestion and neutral detergent fibre digestion increased linearly as the amount of mineral-yeast mixture increased. The mineral-yeast mixture at daily doses of 30 g improved growth performance and digestion in steers grazing star grass pastures. Mineral supplementation with organic sources could improve cattle production under grazing tropical systems. [ABSTRACT FROM AUTHOR]

Nowadays, the experiments related to High Energy Physics and others fields demand the use of detectors with greater radiation resistance, and the novel material GaAs:Cr has demonstrated excellent radiation hardness compared with other semiconductors. On the basis of evidence obtained in the JINR experiment with the use of 22 MeV electrons beam generated by the LINAC-800 accelerator, an analysis of electron radiation effects on GaAs:Cr and Si detectors is presented. The measured I-V characteristics showed a dark current increase with dose, and an asymmetry between the two branches of behaviors for all detectors. Analyzing the MIP spectra and CCE dose dependence measurements a deterioration process of detectors collection capacity with dose increase was found, although behaviors are somewhat different according to the detector type. The detailed explanation of these effects from the microscopic point of view appears in the text, and are generally linked to the generation of atomic displacement, vacancies and other radiation defects, modifying the energy levels structure of the target material. These changes affect the lifetime and concentration of the charge carriers, and other characteristics of the target material. [ABSTRACT FROM AUTHOR]

Some results obtained with the use of Monte Carlo mathematical simulation of radiation transport in Timepix hybrid detectors based on chromium compensated gallium arsenide are presented in this contribution. The MCNPX, GEANT4, SRIM and MCCM code systems were used for this purpose. The in-depth profiles of the deposited energy by the incident photons within the sensor active volume, the shapes and dimensions of the generated charge carriers clouds for different incident energies and specific geometrical conditions were obtained and presented. The 22Ne ions ranges in the target material for two different energies and the contributions of each energy loss channel were also determined. Finally, for a selected detector irradiated with photons of different energies, the displacement cross sections for each chemical element in the active material, as well as the number of displacements per atoms produced for each atomic species were calculated. [ABSTRACT FROM AUTHOR]

Terrestrial serpentinizing systems harbor microbial subsurface life. Passive or active microbially mediated iron transformations at alkaline conditions in deep biosphere serpentinizing ecosystems are understudied. We explore these processes in the Zambales (Philippines) and Coast Range (CA, USA) ophiolites, and associated surface ecosystems by probing the relevance of samples acquired at the surface to in situ, subsurface ecosystems, and the nature of microbe-mineral associations in the subsurface. In this pilot study, we use microcosm experiments and batch culturing directed at iron redox transformations to confirm thermodynamically based predictions that iron transformations may be important in subsurface serpentinizing ecosystems. Biofilms formed on rock cores from the Zambales ophiolite on surface and in-pit associations, confirming that organisms from serpentinizing systems can form biofilms in subsurface environments. Analysis by XPS and FTIR confirmed that enrichment culturing utilizing ferric iron growth substrates produced reduced, magnetic solids containing siderite, spinels, and FeO minerals. Microcosms and enrichment cultures supported organisms whose near relatives participate in iron redox transformations. Further, a potential ‘principal’ microbial community common to solid samples in serpentinizing systems was identified. These results indicate collectively that iron redox transformations should be more thoroughly and universally considered when assessing the function of terrestrial subsurface ecosystems driven by serpentinization. [ABSTRACT FROM AUTHOR]

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