Revista Internacional de Contaminación Ambiental
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ARCHITECTURAL FEATURES AND CONCEPTION OF OVERALL CONSTRUCTION MODE OF YI SETTLEMENTS
Get PDFYi is an ancient and brilliant nation, with its ancestors rooted in Panxi rift, forming a large number of unique and dazzling national cultures in the long national development path with the nutriment of the Jinsha River and the An’ning River. With the development of times, science and technology promote the integration of national culture. The remote, poor and backward traditional Yi settlements are facing constant impacts of modernization on material and spirit. The renovation of traditional Yi dwellings and the construction of small towns blindly copy the construction model of large and medium-sized cities. The destruction of the living environment is caused by economic development and natural disasters. The destruction of the traditional architectural style of Yi dwellings has changed the living environment of Yi, and the dwellings have gradually lost their long-standing architectural features and advantages. Therefore, it is urgent to improve the income and living standards of the residents in Yi region, build a livable living environment, and protect and inherit the Yi culture. The work analyzed the characteristics of Yi villages in Panzhihua, and proposed the overall construction mode of Yi settlement environment in modernization.Yi is an ancient and brilliant nation, with its ancestors rooted in Panxi rift, forming a large number of unique and dazzling national cultures in the long national development path with the nutriment of the Jinsha River and the An’ning River. With the development of times, science and technology promote the integration of national culture. The remote, poor and backward traditional Yi settlements are facing constant impacts of modernization on material and spirit. The renovation of traditional Yi dwellings and the construction of small towns blindly copy the construction model of large and medium-sized cities. The destruction of the living environment is caused by economic development and natural disasters. The destruction of the traditional architectural style of Yi dwellings has changed the living environment of Yi, and the dwellings have gradually lost their long-standing architectural features and advantages. Therefore, it is urgent to improve the income and living standards of the residents in Yi region, build a livable living environment, and protect and inherit the Yi culture. The work analyzed the characteristics of Yi villages in Panzhihua, and proposed the overall construction mode of Yi settlement environment in modernization
MANEJO DE LOS MEDICAMENTOS VETERINARIOS CADUCOS EN LA ZONA METROPOLITANA DEL VALLE DE MÉXICO
Get PDFIn Mexico, veterinary expired medications are classified as hazardous waste according to the Mexican Official Standard NOM-052-SEMARNAT-2005. Nevertheless, a void in the assignation of responsibility regarding the monitoring and fulfillment of regulations distorts the procedures comprising their managing and final disposal, since medications are still disposed in the garbage or flushed down the toilet or sink. The aim of this study was to know the current situation of the management of these residues in the Metropolitan Zone of Mexico City (MZMC). A survey was conducted including 162 managers of veterinary pharmacies, of which 112 agreed to collaborate. Our findings revealed that more than 95% of the respondents are conscious that their establishments generate diverse types of hazardous waste (including expired medications) and claim that some veterinary medications are expired in their pharmacies. Although 64.3% of the respondents reported they use the service of companies specialized in the removal and/or destruction of expired veterinary medications in the MZMC, there does not exist an interest to corroborate if such enterprises operate in accordance to regulations, if they give a final disposition adapted to these kind of waste or even to know the management way of waste, since 95% of the companies named by the respondents are not registered nor authorized by the Secretariat of Environment and Natural Resources of Mexico. From this study, it is concluded that there are mechanisms in Mexico for the correct environmental management of pharmaceutical waste; however, the absence of specific policies for veterinary expired medications makes management, treatment and/or disposal methods inadequate.En México, los medicamentos veterinarios caducos son considerados residuos peligrosos según la Norma Oficial Mexicana NOM-052-SEMARNAT-2005; sin embargo, un vacío en la responsabilidad de supervisión y cumplimento de la normativa origina un desorden en los procedimientos que comprenden su manejo y disposición, ya que todavía se eliminan junto con los residuos sólidos urbanos o se vierten al drenaje. Con el objetivo de conocer la situación actual del manejo de estos residuos en la Zona Metropolitana del Valle de México (ZMVM), se realizó una encuesta a 162 encargados de establecimientos veterinarios, de los cuales 112 accedieron a colaborar. El estudio reveló que más del 95% de los encuestados está consciente de que sus establecimientos generan diversos tipos de residuos peligrosos (incluyendo medicamentos caducos) y afirmaron que algunos medicamentos veterinarios se les caducan. Aunque el 64.3% de los encuestados informó que recurren al servicio de empresas especializadas en el retiro y/o destrucción de medicamentos veterinarios caducos en la ZMVM, no existe un interés por corroborar si las mismas operan de manera legal, si dan una disposición final adecuada a los fármacos o incluso por conocer las formas de tratamiento a las que recurren, ya que el 95% de las empresas mencionadas por los encuestados no están registradas ni autorizadas por la Secretaría de Medio Ambiente y Recursos Naturales. De este estudio se concluye que si bien en México existen los mecanismos para la correcta gestión ambiental de residuos farmacéuticos, la ausencia de una normatividad específica para medicamentos veterinarios caducos hace que los métodos de manejo, tratamiento y/o disposición final sean inadecuados
CUANTIFICACIÓN DE LAS ESPORAS DE Ganoderma DEL AIRE EXTERIOR EN LA CIUDAD DE VILLAHERMOSA, TABASCO, MÉXICO
Get PDFFungal propagules are the more abundant bio-particles in the atmosphere. Their amount depends on several factors, including time of day, season of the year, human activity, speed and direction of the wind, among others. The Ganoderma genus has been studied as a phytopathogen, as a lignocellulose degrading and for its medicinal properties. Moreover, when its basidiospores are inhaled, they can cause allergies in susceptible people. Therefore, its behavior in the atmosphere has been under study in different parts of the world, though in Mexico it has not been studied yet. To determine the quantitative presence of Ganoderma spores in the outer atmosphere of the city, a Burkard type trap was used, which was placed at a height of approximately 10 m at two sites located in an urban and a suburban area. Spores were quantified, and the average hourly and daily concentration was determined. During the sampling period (August 2014-January 2015) a total of 3230 spores were collected form the atmosphere in both sites. In the urban site a total of 1187 spores were quantified, while in the suburban site 2043 spores were obtained. The highest concentration of spores was recorded in August and the lowest in November. Regarding the time variation, the highest concentrations of Ganoderma were recorded at 01:00, 03:00 and 05:00 h. This is the first study on the concentration of Ganoderma spores in southeastern Mexico.Los propágulos fúngicos son las partículas biológicas más abundantes en la atmósfera. La cantidad de éstos depende de muchos factores, entre ellos la hora del día, la estación del año, la actividad humana, y la velocidad y dirección del viento, entre otros. El hongo del género Ganoderma tiene importancia como fitopatógeno y degradador de lignocelulosa, así como por sus propiedades medicinales. Además, cuando sus basidiosporas se inhalan pueden causar alergias en personas susceptibles. Por este motivo su comportamiento en la atmósfera ha sido estudiado en diferentes partes del mundo, aunque en México no se ha estudiado. Para determinar la presencia cuantitativa de esporas de Ganoderma en la atmósfera exterior de la ciudad, se empleó una trampa tipo Burkard que se colocó a una altura de aproximadamente 10 m en dos sitios, uno urbano y otro suburbano. Se cuantificaron las esporas y se determinó la concentración promedio horaria y diaria. Durante el periodo de muestreo (agosto 2014-enero 2015) se recolectó en los sitios urbano y suburbano un total de 3230 esporasen la atmósfera. En el sitio urbano se cuantificó un total de 1187 esporas, mientras que en el sitio suburbano se obtuvo un total de 2043. La mayor concentración de esporas se registró en agosto y la menor en noviembre. En cuanto a la variación horaria, a la 01:00, 03:00 y 05:00 h se registraron las máximas concentraciones de Ganoderma sp. Éste es el primer estudio sobre la concentración de esporas de Ganoderma que se realiza en el sureste de México
ANÁLISIS DE SUPERVIVENCIA A LA DETECCIÓN Y CORRECCIÓN DE LA CONTAMINACIÓN EN SERIES CON VALORES POR DEBAJO DEL LÍMITE DE DETECCIÓN
Get PDFUnder article 17 of the Water Framework Directive the European Union was required to establish a framework to protect groundwater and set criteria for determining its chemical status and define environmental quality standards. Considering the specific characteristics of contaminants in groundwater, it is necessary to use adequate statistical tests. Annex IV of the Groundwater Directive establishes that all measurements below the limit of quantification (LOQ) must be replaced by half of the highest LOQ, with the exception of total pesticides. Although it is possible to estimate mean values in data censored with a single LOQ, its substitution distorts the confidence intervals used to verify tolerance with thresholds. The official monitoring networks lack series with values below the LOQ. In order to set up a methodological framework for its evaluation, nitrate concentration values have been taken in order to perform a subsequent artificial censorship. Two groundwater bodies with different monitoring characteristics and frequencies have been selected, Plana de Sagunto, in the eastern part of Spain, and a sector of the Central Valley (Chile), located around the systems of Tinguirica and Antivero rivers. Through the simulation of different percentages of censorship to data, several methods have been tested. Specific techniques for estimating censored values, such as Kaplan-Meier or robust regression have proven to be the most efficient to verify compliance with environmental standards.El artículo 17 de la Directiva Marco del Agua insta a la Comisión y al Parlamento europeos a proteger el agua subterránea, y establece los criterios para determinar su estado químico y definir estándares de calidad ambiental. Si consideramos las características específicas de los contaminantes en agua subterránea, es preciso utilizar ensayos estadísticos adecuados. En el anexo IV de la Directiva de Aguas Subterráneas se establece que las medidas por debajo del límite de cuantificación (LC) deben sustituirse por la mitad del LC más alto, con la excepción de plaguicidas totales. Aunque es posible estimar valores medios en datos censurados con un único LC, su sustitución distorsiona los intervalos de confianza usados para verificar la tolerancia con umbrales. Las redes oficiales de monitoreo presentan escasos registros con valores por debajo del LC. Con objeto de establecer un marco metodológico para su evaluación, se han tomado valores de concentración de nitratos para realizar posteriormente una censura artificial. Se han seleccionado dos cuerpos de agua subterránea con diferentes características y frecuencias de monitoreo: la Plana de Sagunto, en la zona oriental de España, y un sector del Valle Central (Chile), situado en torno a los sistemas fluviales de los ríos Tinguirica y Antivero. Mediante la simulación de diferentes porcentajes de censura a los datos se han ensayado varios métodos. Se ha demostrado que las técnicas específicas de estimación de valores censurados, como Kaplan-Meier o regresión robusta ser las más eficientes para verificar el cumplimiento de los estándares ambientales
MODELO DE REGRESIÓN LINEAL MÚLTIPLE PARA ESTIMAR CONCENTRACIÓN DE PM1
Get PDFDuring 2014-2015, in the Sartenejas Valley, Greater Caracas, Venezuela, samples of particulate matter (PM) were collected using a cascade impactor that segregates PM in six ranges of particle sizes: > 7.2 μm, 3.0-7.2 μm, 1.5-3.0 μm, 0.95-1.5 μm, 0.49-0.95 μm, and < 0.49 μm, together with local weather data. As a complement, we investigated the occurrence of forest fires and rains for the sampling period, as well as the monthly historical accumulated precipitation for the Greater Caracas. The objective of this investigation was to obtain a linear multivariate model for the prediction of PM1 from environmental, meteorological and physical eventualities in an inter-tropical region in the center-north of Venezuela. Making use of the information from sampling and information from secondary sources, a data matrix was constructed with environmental, meteorological and eventualities variables capable of predicting the behavior of fine particles (PM1) based on other PM sizes, temperature, historical precipitation, occurrence of fires and rains. Finally, a multiple linear regression model was constructed to estimate average concentrations of PM1 from the occurrence of forest fires, concentration of PM in the range of 3.0-0.95 μm, and the historical average of monthly-accumulated precipitation. The variance of PM1 is explained in more than 75% from these variables (R2 = 0.759, p <0.000). The model was validated using the average bias error indicator, which underestimates the predicted values.Durante 2014-2015, en el Valle de Sartenejas, Gran Caracas, Venezuela, se recolectaron muestras de material particulado (PM, por sus siglas en inglés) usando un impactador de cascada que segrega el PM en seis rangos de tamaños de partículas: > 7.2 μm, 3.0 a 7.2 μm, 1.5 a 3.0 μm, 0.95 a 1.5 μm, 0.49 a 0.95 μm y < 0.49 μm, junto con datos de la meteorología del lugar. Como complemento se recolectaron las fechas de ocurrencia de incendios forestales y lluvias para el periodo de muestreo, así como la precipitación acumulada histórica mensual de la Gran Caracas. El objetivo de esta investigación fue obtener un modelo lineal multivariante para la predicción de PM1 a partir de variables ambientales, meteorológicas y eventualidades físicas en una región intertropical del centro-norte de Venezuela. Utilizando la información del muestreo y de fuentes secundarias se construyó una matriz de datos con variables ambientales, meteorológicas y eventualidades capaces de predecir el comportamiento de las partículas finas (PM1) a partir de otros tamaños de partículas, temperatura, histórico de precipitación, ocurrencia de incendios y de lluvias. Finalmente, se construyó un modelo de regresión lineal múltiple para estimar concentraciones promedio de PM1 a partir de la ocurrencia de incendios forestales, la concentración de PM en el rango de 3.0 a 0.95 µm y el histórico del promedio mensual de precipitación acumulada. La varianza de PM1 se explica en más del 75 % de los casos a partir de esas variables (R2 = 0.759; p < 0.000). Se validó el modelo usando el indicador de error de sesgo promedio, el cual subestima los valores pronosticados
EVALUACIÓN DE LAS CARACTERÍSTICAS DE CALIDAD Y BROMATOLÓGICAS DE ENSILADOS ELABORADOS CON RESIDUOS DE calabaza (Cucurbita argyrosperma)
Get PDFPumpkin pulp shell (PPS) is an agricultural by-product with contaminating potential that can be used to ensile. The objective of this study was to determine the quality and bromatological characteristics of ensilages made with PPS, pangola grass hay, urea and two percentages of fermented molasses during 14 and 21 days. Ensilage types (2 kg) were E1 (72.5% PPS, 22.5% grass, 3% molasses and 2% urea) and E2 (72.5% PPS, 19.5% grass, 6% molasses and 2% urea). Both ensilages were fermented for 14 and 21 days. The pH was evaluated, along with dry matter (DM), lactic acid, ash (As), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and hemicellulose content. The statistical analysis was a completely randomized 2 × 2 design with ensilage types and fermentation time as factors. The pH of E2 did not vary (p > 0.05) at 14 and 21 days of fermentation, averaging 3.85. A higher production of lactic acid was quantified with E1 at 14 days, and it also presented a higher DM than E2 (p ≤ 0.05). The content of CP, NDF, ADF, As and hemicellulose did not show differences (p > 0.05) by ensilage type or fermentation times. It is concluded that PPS can be ensiled with pangola grass hay, urea and up to 6% sugarcane molasses fermented for 14 or 21 days without affecting its quality and bromatological characteristics.La cáscara con pulpa de calabaza (CPC) es un subproducto agrícola con potencial contaminante que puede usarse para ensilar. El objetivo fue determinar las características de calidad y bromatológicas de ensilados elaborados con CPC, heno de pasto pangola, urea y dos porcentajes de melaza fermentados durante 14 y 21 días. Los tipos de ensilado (2 kg) fueron los siguientes: E1: 72.5 % de CPC, 22.5 % de pasto, 3 % de melaza y 2 % de urea; E2: 72.5 % de CPC, 19.5 % de pasto, 6 % de melaza y 2 % de urea. Ambos ensilados se fermentaron por 14 y 21 días. Se evaluaron los siguientes elementos: pH, contenido de materia seca (MS), ácido láctico, cenizas (Ce), materia orgánica (MO), proteína cruda (PC), fibra detergente neutro (FDN), fibra detergente ácida (FDA) y hemicelulosa. El análisis estadístico fue un diseño completamente al azar con arreglo factorial 2 × 2, con tipos de ensilado y tiempo de fermentación como factores. El pH de E2 no varió (p > 0.05) a los 14 y 21 días de fermentación, promediando 3.85. Se cuantificó mayor producción de ácido láctico en E1 a 14 días; asimismo, este ensilado presentó mayor MS que E2 (p ≤ 0.05). El contenido de PC, FDN, FDA, Ce y hemicelulosa no mostraron diferencias (p > 0.05) por tipo de ensilado ni tiempos de fermentación. En conclusión, la CPC puede ensilarse con heno de pasto pangola, urea y hasta 6 % de melaza de caña de azúcar fermentada por 14 o 21 días sin afectar sus características de calidad y bromatológicas.
NIVEL DE CONTAMINACIÓN DE METALES Y ARSÉNICO EN AGUAS RESIDUALES Y SUELOS EN LA SUBCUENCA DEL ALTO BALSAS EN TLAXCALA Y PUEBLA, MÉXICO
Get PDFThe objective of this work was to determine if metals and As contained in agricultural soils irrigated with wastewater are of anthropic or natural origin. For this, the geoaccumulation index and the enrichment factor were calculated from the content of Cd, Pb, Ni, Cu, Co, Cr, Zn and As, in the irrigated soils with the wastewater of the Atoyac and Zahuapan rivers, as well as the Valsequillo channel. Samples of wastewater and soil were collected in 16 sites grouped into four zones in two seasons of the year (summer and spring). The determination of metals and As was carried out with a plasma optical emission spectrometer with inductive coupling (ICP-OES) after digestion in a microwave equipment. The differences (p < 0.05) between sources of wastewater coincide with their origin, where the Atoyac river has the highest concentration of Pb. The metals and As in water did not exceed the levels allowed by the NOM-001-ECOL-1996 and the regulations of the Canadian Council of Ministers of the Environment and only the Cu was higher than the value established by the legislation of Spain. The soils showed a metal and arsenic content in decreasing order: Zn (22.8) > Cr (17.7) > Ni (14.8) > Pb (14.7) > Cu (13.06) > Co (5.5) > As (5.3) > Cd (1.2) mg/kg. The geoaccumulation index was 0.003 to 3.0, Cd the one with the highest geoaccumulation. The enrichment factor fluctuated from 1.84 to 6.0. Both indices show the existence of anthropic contamination of agricultural soils in the Alto Balsas sub-basin.El objetivo de este trabajo fue determinar si los metales y el As contenidos en los suelos agrícolas irrigados con aguas residuales son de origen antrópico o natural. Para ello se calcularon el índice de geoacumulación y el factor de enriquecimiento a partir del contenido de Cd, Pb, Ni, Cu, Co, Cr, Zn y As en los suelos irrigados con las aguas residuales de los ríos Atoyac y Zahuapan, así como el canal de Valsequillo. Se recolectaron muestras de agua residual y suelo en 16 sitios agrupados en cuatro zonas en dos temporadas del año (verano y primavera). La determinación de metales y As se realizó con un espectrómetro de emisión óptica de plasma con acoplamiento inductivo (ICP-OES, por sus siglas en inglés), previa digestión en un equipo de microondas. Las diferencias (p < 0.05) entre fuentes de agua residual coinciden con el origen de éstas, donde el río Atoyac presenta la mayor concentración de Pb. Los metales y el As en agua no rebasaron los niveles permitidos por la NOM-001-ECOL-1996 y las reglas del Consejo Canadiense de Ministros del Medio Ambiente, y solamente el valor del Cu fue superior al establecido por la legislación de España. Los suelos mostraron un contenido de metales y arsénico en orden decreciente: Zn (22.8) > Cr (17.7) > Ni (14.8) > Pb (14.7) > Cu (13.06) > Co (5.5) > As (5.3) > Cd (1.2) mg/kg. El índice de geoacumulación fue de 0.003 a 3.0, siendo el Cd el de mayor geoacumulación. El factor de enriquecimiento varió de 1.84 a 6.0. Ambos índices muestran la existencia de contaminación de origen antrópico en los suelos agrícolas de la subcuenca del Alto Balsas
EVALUACIÓN DEL RIESGO AMBIENTAL DE METALES PESADOS EN LOS SEDIMENTOS SUPERFICIALES DEL SACO DEL GOLFO DE CARIACO
Get PDFThe aim of this study was to assess the potential risk of heavy metals to the ecosystem of the gulf of Cariaco. To this end, we determined the concentration of heavy metals and the contamination and environmental risk indices in sediments. In addition, a survival test with Artemia salina was applied. The total metal concentrations (µg/g) were: Cu (29-91, Χ– = 58), Cd (1.9-4.9, Χ– = 3.7), Cr (4-36, Χ– = 21), Ni (10-33, Χ– =21), Pb (3-9, Χ– = 6) and Zn (32-112, Χ– = 75). Metal concentrations were lower than the sediment quality standards (SQS). In the bioavailable fraction of sediments, the concentration of metals was innocuous. The enrichment factor (EF) showed that Zn, Cd and Cu were enriched by anthropogenic sources. The geoaccumulation index (Igeo) revealed high contamination by Cd. The risk assessment code (RAC) showed that the concentrations of Cd and Cr were innocuous, Cu and Ni were between harmless and scarecely dangerous, and Zn and Mn were moderately hazardous. Finally, Cd, Cu and Ni were the only metals with concentrations ranging between effects range low (ERL) and median (ERM) and the combined toxic potential of the metals was low (21 %). Despite this, no specimen of Artemia salina had negative effects on sedimentary extracts. Therefore, the ecosystem can be considered healthy, which is favored by very fine and anoxic sediments that lead to accumulation of metals.El objetivo de esta investigación fue evaluar la potencialidad de algunos metales pesados para provocar daños al ecosistema del golfo de Cariaco. Para ello se determinaron las concentraciones de los metales en los sedimentos y los índices de contaminación y riesgo ambiental. Además, se realizó una prueba de supervivencia con Artemia salina. Las concentraciones totales (µg/g) fueron: Cu (29-91, Χ– = 58), Cd (1.9-4.9, Χ– = 3.7), Cr (4-36, Χ– = 21), Ni (10-33, Χ– = 21), Pb (3-9, Χ– = 6) y Zn (32-112, Χ– = 75). Todas las concentraciones de metales fueron menores que los estándares de calidad de sedimentos marinos (SQS). En la fracción biodisponible, los metales mostraron concentraciones no tóxicas. El factor de enriquecimiento (FE) reveló incrementos por fuentes antrópicas en Zn, Cd y Cu. El índice de geoacumulación (Igeo) indicó contaminación por Cd. El código de riesgo ambiental (CRA) mostró que las concentraciones de Cd y Pb fueron inocuas; las de Cr, Cu y Ni entre inocuas y poco peligrosas, y las de Zn y Mn medianamente peligrosas. Finalmente, las concentraciones de Cd, Cu y Ni se ubicaron entre el intervalo de efectos bajos (ERL) y medios (ERM), y la potencialidad tóxica combinada (m-ERM-Q) fue baja (21 %). A pesar de esto, ningún ejemplar de Artemia salina tuvo efecto negativo en los extractos sedimentarios. Por tanto, el ecosistema se considera saludable, condición favorecida por sedimentos muy finos y anóxicos que benefician la retención de metales
PERSISTENT ORGANIC POLLUTANTS IN SERUM AND BREAST MILK OF FERTILE-AGED WOMEN
Get PDFPersistent organic pollutants (POPs) can be transferred through the placenta and breast milk to the developing human offspring, carrying immediate and delayed health risks. We sought to evaluate potential levels of exposure to POPs during critical windows of development: pregnancy and lactation. Two cross-sectional studies were carried out in villages of the states of Sonora and Sinaloa in Mexico, where high levels of POPs have been detected through environmental and human monitoring. POPs were measured in the serum of 60 fertile-aged women in the first study. Breast milk POPs concentrations were measured in a pooled sample of 50 women in the second study. This may be the first study in Mexico to report breast milk dioxins’ and furans’ concentrations. The most commonly detected POPs in serum were: pentachloroanisole (71 %), PCB 205 (43 %), tetrachlorobenzenes (17-33 %), p,p’DDE (21 %), and toxic lindane by-products α-HCH or β-HCH (15 %). Congeners of furans and dioxins with the highest concentrations in milk were 2,3,4,7,8-PeCDF (3.42 pg/g) and OCDD (33.0 pg/g), respectively. The ∑ PCDD/Fs found in this study was lower than in other studies. Both serum and milk samples of fertile-aged women suggest that p,p’DDE and PCB 180 are prevalent local POPs, among others, that may reach developing embryos and infants via the placenta and lactation. These results can serve as a starting point to determine potential levels of exposure to POPs in the most vulnerable stages of life and to evaluate concentration trends in the process of eliminating these compounds.Persistent organic pollutants (POPs) can be transferred through the placenta and breast milk to the developing human offspring, carrying immediate and delayed health risks. We sought to evaluate potential levels of exposure to POPs during critical windows of development: pregnancy and lactation. Two cross-sectional studies were carried out in villages of the states of Sonora and Sinaloa in Mexico, where high levels of POPs have been detected through environmental and human monitoring. POPs were measured in the serum of 60 fertile-aged women in the first study. Breast milk POPs concentrations were measured in a pooled sample of 50 women in the second study. This may be the first study in Mexico to report breast milk dioxins’ and furans’ concentrations. The most commonly detected POPs in serum were: pentachloroanisole (71 %), PCB 205 (43 %), tetrachlorobenzenes (17-33 %), p,p’DDE (21 %), and toxic lindane by-products α-HCH or β-HCH (15 %). Congeners of furans and dioxins with the highest concentrations in milk were 2,3,4,7,8-PeCDF (3.42 pg/g) and OCDD (33.0 pg/g), respectively. The ∑ PCDD/Fs found in this study was lower than in other studies. Both serum and milk samples of fertile-aged women suggest that p,p’DDE and PCB 180 are prevalent local POPs, among others, that may reach developing embryos and infants via the placenta and lactation. These results can serve as a starting point to determine potential levels of exposure to POPs in the most vulnerable stages of life and to evaluate concentration trends in the process of eliminating these compounds
EMISIÓN DE N2O, CO2 Y NH3 A PARTIR DE ESTIÉRCOL DE BOVINOS CON DIFERENTE PORCENTAJE DE PROTEÍNA CRUDA EN LA DIETA
Get PDFThe emission of nitrous oxide (N2O), carbon dioxide (CO2) and ammonia (NH3) in tropical dairy cattle (CLT) excreta, fed with different percentages of crude protein (CP), was quantified using static cameras. Sampling was performed at different times of day (7:00, 10:00, 13:00, 16:00, and 19:00 local time -LT-). The statistical model employed was a covariance analysis in a randomized complete block design with repeated measures. The variables were analyzed using the Glimmix procedure of the Statistical Analysis System (SAS) v. 9.2 with a covariance structure of compound symmetry. The best model that explains the flow of N2O-N and the emission of CO2 and NH3 is that which included the minimum ambient temperature and the pH as covariates, respectively. Treatment with 12 % of CP obtained the highest N2O-N flow and the lowest CO2 emission. Treatment with 14 % CP had the lowest N2O emission and treatments with 14 and 16 % CP reflected higher amounts of CO2 emissions. The hours of the day when there were greater emissions of NH3 were 10:00 and 13:00 LT, which in turn were the hours where less amount of CO2 and N2O was emitted. As the percentage of CP in the different treatments increases, there is also an increase in the weight gain of the animal, being the treatment with 16 % CP, commercial food, the diet that produced the highest increase in kilograms in animals.Se cuantificó la emisión de óxido nitroso (N2O), dióxido de carbono (CO2) y amoniaco (NH3) en excretas de bovinos de raza criollo lechero tropical (CLT) alimentados con diferentes porcentajes de proteína cruda (PC), mediante el uso de cámaras estáticas. El muestreo de gases se realizó a diferentes horas del día (7:00, 10:00, 13:00, 16:00 y 19:00 hora local -HL-). El modelo estadístico usado fue un análisis de covarianza en un diseño de bloques completos al azar con medidas repetidas. La emisión de gases se analizó mediante el procedimiento Glimmix del Statistical Analysis System (SAS) v. 9.2, con una estructura de covarianza de simetría compuesta. El modelo que mejor explica el flujo de N2O-N y la emisión de CO2 y NH3 es aquel que incluyó como covariable la temperatura mínima ambiental y el pH, respectivamente. El tratamiento con 12 % de PC obtuvo el mayor flujo de N2O-N y la menor emisión de CO2. El tratamiento con 14 % de PC tuvo la emisión más baja de N2O y los tratamientos con 14 y 16 % de PC reflejan mayores flujos de emisión de CO2. Las horas del día en que hubo mayor emisión de NH3 fueron las 10:00 y 13:00 HL, que a su vez fueron las horas en que se emitió menor cantidad de CO2 y N2O. Por último, a medida que aumenta el porcentaje de PC en los diferentes tratamientos, hay un incremento en la ganancia en peso del animal, siendo el tratamiento con 16 % de PC, alimento comercial, la dieta que produjo mayor aumento en kilogramos