Desarrollo, ética y tecnología

Las fuertes modificaciones del clima ob- servadas últimamente, los períodos de invierno prácticamente continuos, los pro- longados estiajes, la disminución de la calidad del agua de las fuentes de abas- tecimiento superficiales y subterráneas y otros extraños fenómenos, revelan la preocupante situación a la que ha llega- do nuestro planeta desde el punto de vis- ta ambiental, y pone de relieve el modelo económico que ha imperado en el mundo, en el corto tiempo que ha necesitado para alcanzar este nivel de deterioro.Cuencanúmero 2

Estudio integral de la calidad del agua del río Burgay y evaluación del riesgo toxicológico por la probable presencia de plaguicidas

Se estudia la calidad del agua del río Burgay en la Provincia del Cañar, empleando índices: ICA del Instituto Mexicano de Tecnología del Agua, para la calidad físico-química y bacteriológica; y BMWP (BiologicalMonitoringWorkingParty) para la calidad biológica, basado en macroinvertebrados acuáticos. La actividad agrícola y ganadera es preponderante en la microcuenca, por lo que se evalúa también la contaminación difusa que recepta el río por la presencia de plaguicidas, y el riesgo toxicológico asociado; algunas estaciones de monitoreo, superaron las concentraciones permitadas por la Normativa Ecuatoriana Tulas, para fuentes destinadas a abastecimiento humano y que sólo requieren desinfección: 10 ppb para los plaguicidas órgano clorados (OC), y 100 ppb para los plaguicidas órgano fosforados (OF). Este estudio integral, define los usos a los que puede destinarse el recurso, abastecimiento público, recreativo, pesca y vida acuática, agrícola e industrial. La evaluación se realizó mediante un monitoreo sistemático por un período de diez meses, de Febrero a Noviembre del año 2013. Se plantea la necesidad de interceptar las aguas residuales domésticas de las poblaciones mayores ubicadas en la microcuenca, y que actualmente descargan al cuerpo receptor; así como la implementación de un sistema de vigilancia de plaguicidas, en el agua destinada a consumo humano, en las comunidades que usan el recurso, sin tratamiento previo.Water quality of the Burgay river basin in the Province of Cañar - Ecuador was studied by using two water quality indices: ICA of the Mexican Institute of Water Technology, for the physical- chemical and bacteriological quality; and BMWP (Biological Monitoring Working Party) for the biological quality based on aquatic macro-invertebrates. Crop and livestock activity is predominant in the basin, therefore diffuse pollution was also assessed by the presence of pesticides and associated toxicological risk; some monitoring stations exceeded concentrations permitted by the Ecuadorian Legislation called “Tulas” to sources intended for human supply and just require disinfection: 10 ppb for organ chlorinated pesticides (OC), and 100 ppb for organ pesticides phosphorus (OF). This comprehensive study identifies the uses to which the water resource can be used: public water supply, recreation, fishing and aquatic, agricultural and industrial life. The evaluation was performed by systematic monitoring for a period of ten months, from February to November 2013. There is a need to intercept domestic wastewater of the largest populations in the basin, which is currently discharged directly to the river; and implementing a monitoring system for pesticides in drinking water of communities that use the resource, without pre-treatment.Magister en Toxicología Industrial y AmbientalCuenc

Control de calidad de las mermeladas de mayor consumo en nuestro medio

Definiendo alimento como toda sustancia que incorporada al organismo sea capaz de contribuir a asegurar la constancia, en cantidad y calidad de las sustancias específicas de éste. Para el mejor control de la calidad de la producción acorde con las necesidades y exigencias de los consumidores. El control de calidad se define como un sistema de inspección análisis y actuación aplicada a una operación de fabricación, de manera tal que, inspeccionada una pequeña cantidad del producto corrientemente producido, se puede estimar su calidad completa y determinada, si fuera necesario, qué cambios deben ser realizados en el proceso de elaboración para alcanzar y mantener el nivel de calidad requerido.Doctor en Bioquímica y FarmaciaCuenc

Traffic and Industrial Contributions of Particle-Bound PAHs during an Air Pollution Event in the Metropolitan Area of Medellin-Colombia

Air pollution includes particle-bound polycyclic aromatic hydrocarbons (PAHs), which eventually reach the placenta, triggering adverse perinatal outcomes through long-term exposure. Lately, air pollution has increased over the Metropolitan Area of Medellin-Colombia (MAMC), but its effects on pregnancy are still unknown. In this research, a real-time analysis of total airborne PAHs was made using a photoelectric sensor for residential places influenced by the industrial and traffic sources affecting the southern and northern MAMC during the second peak of the bimodal tendency for PM2.5 emissions in this region. Additionally, individual PAHs were analyzed by GC/MS coupled with pressurized hot water extraction methodology. The data were applied using an inhalation intake model to assess pregnancy exposure. The average concentration of PAHs in the southern MAMC was three times higher than in the northern MAMC, where the missed abortion rate has been 1.4 times higher according to the database. Previous research indicates that PAHs act as endocrine-disrupting chemicals (EDCs) during pregnancy and that even heavy congeners could reside in umbilical cord blood. Finally, the annual series of missed abortion rates in the MAMC exhibited a significant correlation with the annual average levels of PM2.5, which were associated with PAHs through correlation analysis (r2 = 0.69, p < 0.01). While this significant correlation does not imply causality, our results suggest an important connection between both variables, opening a gap for a deeper understanding of how regions with high PAH convergence influence the missed abortion rates in MAMC

Bacterial and Parasitic Characterization of the Rivers in Cuenca, Ecuador

Cryptosporidium and Giardia are infectious parasitic forms widely distributed in aquatic ecosystems and resistant to disinfection of drinking water. Their presence was investigated in the lower areas of the city’s four rivers through a four-stage methodology. Between December 2017 and April 2018, three monitoring campaigns were conducted, with results ranging between not detected to 500 oocysts/L for Cryptosporidium, and between not detected and 300 for Giardia. Cryptosporidium was more abundant, especially in the Machángara River. In the same period, the bacteriological quality of the rivers was also reviewed using Total Streptococci and Fecal Enterococci expressed in colony-forming units (CFU)/100 mL as indicators. The results showed a progressive increase in pollution as the course of the rivers progressed. The sensitivity of bacterial indicators to changes in quality is also observed, which is why their use in specific studies is recommended. It is concluded that untreated domestic wastewater discharges may be the main source of contamination by bacteria and parasites and that there is a relationship between their concentration and the seasonal period. In dry weather, the concentration is higher for both microorganisms. This study fills a gap in knowledge in the region, due to the absence of data on parasitic indicators with great impacts on public health

Evaluación de la calidad del agua de los ríos de la ciudad de Cuenca, Ecuador

The water quality of the Tarqui, Yanuncay, Machángara and Tomebamba rivers, tributaries of the Paute river was evaluated. Due to the need to incorporate new approaches in the water quality monitoring, this study applied the widely known water quality index (WQI) but, instead of using the 9 parameters originally required by the method, we used 18 physicochemical and microbiological parameters. For each river, nine monitoring campaigns were carried out, covering representative hydrological periods and measuring flow discharges. The results show that, in general, in the areas of river catchment, the water resource is suitable for almost all types of use, but gradually, as it progresses downstream, the quality decreases due to sanitary or industrial wastewater and to natural factors such as runoff or erosion sediments. The most critical condition of the evaluated river’s water quality was presented during drought conditions, mainly due to the decrease in dissolved oxygen and the increase in temperature, salinity, organic matter and coliform bacteria. On the other hand, during rainy periods, parameters indicating a decrease of water quality were color, turbidity, and nutrient content such as phosphorus and nitrogen. In general, rivers have better quality for medium flow conditions, which prevail during most of the year. The present results were analyzed in accordance with the quality objectives established in previous studies, allowing a qualitative evaluation of the wastewater interception and treatment system of the city of Cuenca, Ecuador.Se evaluó la calidad del agua de los ríos Tarqui, Yanuncay, Machángara y Tomebamba, afluentes del río Paute. En línea con la necesidad de incorporar nuevos enfoques en la vigilancia de la calidad del agua, este estudio aplicó el ampliamente conocido Water Quality Index (QWI) pero, en lugar de utilizar los nueve parámetros originalmente requeridos por el método, utilizamos 18 parámetros fisicoquímicos y microbiológicos. Para cada río, se llevaron a cabo nueve campañas de monitoreo, cubriendo períodos hidrológicos representativos y midiendo descargas de flujo. Los resultados muestran que, en general, en las áreas de captación de los ríos, el recurso hídrico es adecuado para casi todo tipo de uso, pero gradualmente, a medida que avanza aguas abajo, la calidad disminuye debido a las descargas de aguas residuales sanitarias, industriales y a factores naturales como escorrentía o sedimentos por erosión. La condición más crítica de calidad de las aguas evaluadas se presentó durante las condiciones de sequía, principalmente debido a la disminución del oxígeno disuelto y al aumento de la temperatura, la salinidad, la materia orgánica y las bacterias coliformes. Por otro lado, durante los períodos lluviosos, los parámetros indicadores de una disminución en la calidad del agua fueron el color, la turbidez, y el contenido de nutrientes como fósforo y nitrógeno. En general, los ríos tienen mejor calidad para condiciones de flujo medio, que prevalecen durante la mayor parte del año. Los presentes resultados se analizaron de acuerdo con los objetivos de calidad establecidos en estudios anteriores, permitiendo una evaluación cualitativa del sistema de intercepción y tratamiento de aguas residuales de la ciudad de Cuenca, Ecuador. la Vigilancia de la Calidad del Agua

Indicadores bacteriológicos de contaminación fecal en los ríos de Cuenca, Ecuador

Given the necessity to reliably control the microbiological condition of water, it is recommended to select indicators of fecal contamination sensitive to changes in quality. In this research, the contamination of the rivers Tomebamba, Tarqui, Yanuncay, and Machángara of the city of Cuenca was analyzed, using the traditional bacterial indicators Total Coliforms and Fecal Coliforms. In parallel, the bacterial indicators Fecal Streptococci and Enterococci were used as alternative and/or complementary indicators, given their evidence shown in several water quality studies. All these organisms come from the gastrointestinal tract of man and warm-blooded animals and are excreted through the feces. Three monitoring campaigns were conducted in each river during representative hydrological flow conditions, respectively of high, medium, and low flow. A total of 78 samples was collected, and the Multiple Tubes technique, expressed as MPN/100 ml, was used for the quantification of the indicators. The results showed significant differences in quality between the sections of the 4 rivers and suggest that Fecal Streptococci and Enterococci perform satisfactory as indicators of fecal contamination. They provide accurate and reliable information with respect to the safe uses of the water resource and complement the diagnosis obtained by the traditional indicators. The relationships between the indicators permitted to identify possible sources of contamination. Furthermore, the comprehensive evaluation of the microbiological water quality of the examined rivers suggests that the use of traditional and alternative indicators, especially in peculiar environments, permits to define the most appropriate corrective measures to control the contamination.Ante la necesidad de un control fiable de la condición microbiológica del agua es imprescindible la selección de indicadores de contaminación fecal sensibles a cambios en la calidad. En esta investigación se revisó la contaminación de los ríos de la ciudad de Cuenca: Tomebamba, Tarqui, Yanuncay y Machángara, empleando indicadores bacterianos tradicionales como los Coliformes Totales y Coliformes Fecales, y además los Estreptococos Fecales y Enterococos por su importancia en estudios de calidad de agua como indicadores alternativos y/o complementarios; todos los organismos proceden del tracto gastrointestinal del hombre y de los animales de sangre caliente y son excretados a través de las heces. Se realizaron tres campañas de monitoreo en cada río cubriendo períodos hidrológicos representativos: caudal alto, medio y bajo y en estaciones específicas, con un total de 78 muestras puntuales; se utilizó la técnica de los Tubos Múltiples expresado como NMP/100 ml, para la cuantificación de los indicadores. Los resultados evidenciaron diferencias significativas de calidad entre tramos de cuenca y mostraron que los Estreptococos Fecales y los Enterococos se desempeñan como indicadores satisfactorios de contaminación fecal; aportan información al momento de definir los usos del recurso y complementan el diagnóstico brindado por los indicadores tradicionales; las relaciones entre indicadores permitieron identificar las posibles fuentes de contaminación. La evaluación integral de la calidad microbiológica de los cuerpos superficiales sugiere el uso de indicadores tradicionales y alternativos, sobre todo en ambientes peculiares, a la vez que permite tomar medidas correctivas específicas para el control de la contaminación

Model based analysis of the growth kinetics of microalgal species residing in a waste stabilization pond

BACKGROUND: In this study the growth kinetics of Chlorella and Scenedesmus, isolated from a Waste Stabilization Pond were investigated under different conditions of light intensity and temperature. Experimental data were collected by means of a combined respirometric and titrimetric set-up and used to extend a mathematical model. RESULTS: The experimental results illustrated the interdependent relationship of light intensity and temperature, which had a significant influence on the microalgal growth. Consequently, a previously developed model was extended with a mathematical function that describes this relationship. The maximum specific growth rate and oxygen mass transfer coefficient were considered for model calibration. The optimized parameter values for Chlorella were μmax = 0.56 ± 0.0008 d−1 and KLa = 10.02 ± 0.02 d−1. For Scenedesmus, the optimized parameter values were μmax = 0.19 ± 0.0004 and KL a = 7.71 ± 0.004 d−1. The model with optimized parameter settings described the dissolved oxygen production (derived from the respirometric data) and the related proton consumption (derived from the titrimetric data) reasonably well for both microalgal species. The threshold value for Theil's Inequality Coefficient of 0.3 was never exceeded. In addition, model validation for both species was performed indicating good correspondence between model prediction and experimental values. CONCLUSIONS: Based on the experimental observations, a previously developed mathematical model was extended with a function that describes the interaction between light intensity and temperature. After model calibration a difference in maximum specific growth rate between the two microalgal species was observed. This might be explained by differences in cell metabolism. © 2016 Society of Chemical Industry. © 2016 Society of Chemical IndustryBACKGROUND: In this study the growth kinetics of Chlorella and Scenedesmus, isolated from a Waste Stabilization Pond were investigated under different conditions of light intensity and temperature. Experimental data were collected by means of a combined respirometric and titrimetric set-up and used to extend a mathematical model. RESULTS: The experimental results illustrated the interdependent relationship of light intensity and temperature, which had a significant influence on the microalgal growth. Consequently, a previously developed model was extended with a mathematical function that describes this relationship. The maximum specific growth rate and oxygen mass transfer coefficient were considered for model calibration. The optimized parameter values for Chlorella were μmax = 0.56 ± 0.0008 d−1 and KLa = 10.02 ± 0.02 d−1. For Scenedesmus, the optimized parameter values were μmax = 0.19 ± 0.0004 and KL a = 7.71 ± 0.004 d−1. The model with optimized parameter settings described the dissolved oxygen production (derived from the respirometric data) and the related proton consumption (derived from the titrimetric data) reasonably well for both microalgal species. The threshold value for Theil's Inequality Coefficient of 0.3 was never exceeded. In addition, model validation for both species was performed indicating good correspondence between model prediction and experimental values. CONCLUSIONS: Based on the experimental observations, a previously developed mathematical model was extended with a function that describes the interaction between light intensity and temperature. After model calibration a difference in maximum specific growth rate between the two microalgal species was observed. This might be explained by differences in cell metabolism. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industr

Comparación de las eficiencias de recuperación de lípidos de las microalgas Chlorella y Scenedesmus obtenidas con diferentes disolventes

The lipids of microalgae are the source for obtaining third-generation biofuels so that fossil fuels can be replaced. The objectives of this study were to determine the composition of the lipids of Chlorella and Scenedesmus microalgae using the gravimetric method; Determine the efficiency of different solvents for the extraction of lipids with the Soxhlet method and compare the lipid recovery productivities of Chlorella microalgae with thermal and physical pretreatments. The highest amount of lipids, 20.37% per dry sample, the microalga, the chlorella, the solvent mixture, the chloroform:methanol in a 1:2 ratio. The increase in the amount of lipids generated with the use of pretreatments no justifies its use for which it is recommended that no pretreatment be applied. The results allow to establish a baseline in the use of microalgae cultivable in the Ecuadorian mountain to obtain lipids for biofuels.Las microalgas son capaces de producir lípidos que pueden ser usados para obtener biocombustibles de tercera generación, los cuales buscan reemplazar a los combustibles fósiles. Los objetivos de este estudio fueron: determinar la composición de lípidos de las microalgas Chlorella y Scenedesmus usando el método gravimétrico; determinar la eficiencia de diferentes solventes para la extracción de lípidos con el método Soxhlet; y comparar las productividades de recuperación de lípidos de las microalgas Chlorella obtenidas con pretratamientos térmico y físico. Los resultados obtenidos muestran que se recuperó la mayor cantidad de lípidos, un 20.37% por muestra seca, en la microalga Chlorella usando una la mezcla de disolventes cloroformo: metanol en proporción 1:2. El aumento de la cantidad de lípidos, generado con el uso de pretratamientos, no justifica su uso, por lo que se recomienda que no se aplique un pretratamiento. Los resultados permiten establecer una línea base en el aprovechamiento de microalgas cultivables en la serranía ecuatoriana para la obtención de lípidos para biocombustibles