Revista Internacional de Contaminación Ambiental
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PESTICIDE RESIDUES MONITORING IN UNDERGROUND DRINKING WATER, NEUQUÉN PROVINCE, NORTHERN PATAGONIA, ARGENTINA
Get PDFNeuquén province is located in the west of Argentina, at the northern end of Patagonia. In this province, information regarding groundwater distribution and quality is very scarce, and the monitoring of water resources quality is not carried out periodically. It is well known that several pesticide families, such us organophosphates, carbamates and neonicotinoids, are applied in this region to maintain crop quality and production. Pesticide application by ground-based spraying equipment, the climatic conditions and the physical and chemical properties of these compounds, facilitate that a substantial fraction of the active ingredient may reach air, soil and water sources. The objective of this study was to evaluate the pesticide presence in groundwater, in order to provide information about the water quality for human consumption. Seventeen organophosphate and four carbamate residues were monitored from 2014 to 2015 by gas chromatography with a nitrogen-phosphorus detector, in groundwater samples collected from depth wells, located in rural areas corresponding to Senillosa, Plottier, Vista Alegre and Centenario cities, in Neuquén province. These cities are intensive agricultural areas, which supply the North Patagonia region with fresh fruits and vegetables, and where groundwater is utilized for human consumption. In this study, organophosphate and carbamate concentrations were below 0.020 and 0.030 µg/L, respectively, and lower than the accepted limits established by the Guidelines for Canadian drinking water quality (2017) and the Guidelines for drinking water quality (2011) of the World Health Organization for these pesticides.Neuquén province is located in the west of Argentina, at the northern end of Patagonia. In this province, information regarding groundwater distribution and quality is very scarce, and the monitoring of water resources quality is not carried out periodically. It is well known that several pesticide families, such us organophosphates, carbamates and neonicotinoids, are applied in this region to maintain crop quality and production. Pesticide application by ground-based spraying equipment, the climatic conditions and the physical and chemical properties of these compounds, facilitate that a substantial fraction of the active ingredient may reach air, soil and water sources. The objective of this study was to evaluate the pesticide presence in groundwater, in order to provide information about the water quality for human consumption. Seventeen organophosphate and four carbamate residues were monitored from 2014 to 2015 by gas chromatography with a nitrogen-phosphorus detector, in groundwater samples collected from depth wells, located in rural areas corresponding to Senillosa, Plottier, Vista Alegre and Centenario cities, in Neuquén province. These cities are intensive agricultural areas, which supply the North Patagonia region with fresh fruits and vegetables, and where groundwater is utilized for human consumption. In this study, organophosphate and carbamate concentrations were below 0.020 and 0.030 µg/L, respectively, and lower than the accepted limits established by the Guidelines for Canadian drinking water quality (2017) and the Guidelines for drinking water quality (2011) of the World Health Organization for these pesticides
OPTIMIZING THE DIFFERENTIAL PULSE ANODIC STRIPPING VOLTAMMETRY METHOD WITH A HANGING MERCURY ELECTRODE FOR THALLIUM (I) DETERMINATION IN THE PRESENCE OF LEAD (II) AND COPPER (II) FOR APPLICATION IN CONTAMINATED SOILS
Get PDFThe conditions that allow thallium (I) determination in the presence of lead (II) and copper (II) were optimized without prior separation of these cations, using a previously developed differential pulse anodic stripping voltammetry (DPASV) method, with a hanging mercury drop working electrode (HMDE) and a Ag/AgCl reference electrode. Unfortunately, the electrochemical activity of lead (II) interferes with this determination, but the addition of 0.1 M EDTA complexing agent (at pH = 4.6) causes a shift in the Pb(II) peak to more negative values, making it possible to quantify Tl(I) in its presence at an optimal deposition potential of –0.550 V. However, the Cu(II) reduction peak, which is normally found far away from that of Tl(I), is also shifted when complexed with EDTA, approaching the Tl(I) peak and becoming an interfering ion. The deposition time and scan rate that were found optimal for the determination were 30 s and 10 mV/s, respectively. Under these conditions it was found that maximum concentration ratios for Pb(II)/Tl(I) and Cu(II)/Tl(I) of 2000 and 400, respectively, did not show interference thus duplicating and quadruplicating the concentrations of Pb(II) and Cu(II), respectively above which interference with Tl(I) occurs, as compared to the standard method published. The proposed methodology has a detection limit of 2 μg/L, a quantification limit of 7 μg/L, and a linear range between 2.3 and 20 μg/L. Enriched Tl solutions of 0.5, 2.5 and 9 μg/L showed excellent recoveries. The methodology was applied to extractions of contaminated soil samples with Tl contents from 0.05 to 3.2 mg/kg.The conditions that allow thallium (I) determination in the presence of lead (II) and copper (II) were optimized without prior separation of these cations, using a previously developed differential pulse anodic stripping voltammetry (DPASV) method, with a hanging mercury drop working electrode (HMDE) and a Ag/AgCl reference electrode. Unfortunately, the electrochemical activity of lead (II) interferes with this determination, but the addition of 0.1 M EDTA complexing agent (at pH = 4.6) causes a shift in the Pb(II) peak to more negative values, making it possible to quantify Tl(I) in its presence at an optimal deposition potential of –0.550 V. However, the Cu(II) reduction peak, which is normally found far away from that of Tl(I), is also shifted when complexed with EDTA, approaching the Tl(I) peak and becoming an interfering ion. The deposition time and scan rate that were found optimal for the determination were 30 s and 10 mV/s, respectively. Under these conditions it was found that maximum concentration ratios for Pb(II)/Tl(I) and Cu(II)/Tl(I) of 2000 and 400, respectively, did not show interference thus duplicating and quadruplicating the concentrations of Pb(II) and Cu(II), respectively above which interference with Tl(I) occurs, as compared to the standard method published. The proposed methodology has a detection limit of 2 μg/L, a quantification limit of 7 μg/L, and a linear range between 2.3 and 20 μg/L. Enriched Tl solutions of 0.5, 2.5 and 9 μg/L showed excellent recoveries. The methodology was applied to extractions of contaminated soil samples with Tl contents from 0.05 to 3.2 mg/kg
PLAGUICIDAS ORGANOCLORADOS EN AGUA DE LA LAGUNA NEGRA DE PUERTO MARQUÉS, ACAPULCO, GUERRERO, MÉXICO
Get PDFThe presence of organochlorine pesticides in aquatic systems is an issue of vital importance, because it affects non-renewable natural resources and as consequence the quality of water for organisms that live and use this resource. Coastal lagoons are aquatic systems that receive a large amount of organic matter and organic (petroleum hydrocarbons and pesticides) and inorganic (heavy metals) pollutants, where the biogeochemical and biological cycles of many species of commercial interest are carried out, as well as tourism activities. The objective of the present work was to quantify the concentrations of organochlorine pesticides in the water of the Laguna Negra of Puerto Marqués, Acapulco. The organochlorine compounds were determined by gas chromatography analysis with electron capture detector (63Ni). The results obtained in the sampling sites were divided into lagoon and discharge sites and did not show a significant difference, since the total average concentrations were 5.55 and 6.02 μg/L, respectively. It was also noted that during the dry season a total average of 6.80 μg/L was recorded, while in the rainy season it was 3.56 μg/L. According to the Official Mexican Standard NOM-SSA1-1994 there should be no organochlorine pesticides. Although concentrations are low (μg/L), they can cause some alteration to organisms through bioaccumulation and biomagnification with risks to the health of the natural system and the human being.La presencia de plaguicidas organoclorados en los cuerpos acuáticos es un tema de vital importancia, debido a que se afecta un recurso natural no renovable y con ello la calidad del agua para los organismos vivos que consumen este recurso. Las lagunas costeras son cuerpos acuáticos que reciben una gran cantidad de aportes de materia orgánica y de contaminantes orgánicos (hidrocarburos de petróleo y plaguicidas) e inorgánicos (metales pesados), y donde se efectúan los ciclos biogeoquímicos y biológicos de muchas especies de interés comercial, así como actividades turísticas. El objetivo del presente trabajo fue cuantificar las concentraciones de plaguicidas organoclorados en el agua de la Laguna Negra de Puerto Marqués, Acapulco. Los compuestos organoclorados se determinaron mediante análisis de cromatografía de gases con detector de captura de electrones (63Ni). Los resultados obtenidos en los sitios de muestreo fueron divididos en cuerpo lagunar y de descarga; no presentaron una diferencia significativa, ya que las concentraciones promedio totales fueron de 5.55 y 6.02 µg/L, respectivamente. Asimismo, se apreció que durante la época de estiaje se registró una media total de 6.80 µg/L, mientras que en la época de lluvia fue de 3.56 µg/L. De acuerdo con la norma oficial mexicana NOM-SSA1-1994 no deben de existir plaguicidas organoclorados, ya que si bien las concentraciones son bajas (µg/L), pueden causar alguna alteración a los organismos por bioacumulación y biomagnificación, con riesgos para la salud del sistema natural y del ser humano
EVALUACIÓN DE RIESGOS A LA SALUD DE LACTANTES EXPUESTOS A METALES TRAZA EN LECHE MATERNA
Get PDFThe aim of this study was to assess the health risk of infants between 0 and 24 months of age due to ingestion of breast milk containing cadmium (Cd), mercury (Hg) and lead (Pb). The non-carcinogenic risk (NCR) was quantified using probabilistic models with the Crystal Ball® program, following the model guidelines of the United States Environmental Protection Agency (USEPA). The average of the maximum measured levels of Cd (8.87 μg/kg) Hg, (20.88 μg/kg) and Pb (37.29 μg/kg) was 5, 21 and 19 times, respectively, above the maximum limits allowed by the World Health Organization. Regarding risk, the values associated with the content of at least one of the metals in breast milk could exceed the maximum limits allowed by the USEPA at each sampling site and each subgroup of babies (NCR ≥ 1). The first evidence of contamination by heavy metals in the breast milk of women living on the banks of the Cauca river was presented. In isolated cases, babies exposed by the intake of this milk, exceed the tolerable consumption of these contaminants. Taking into account the worst scenario, children in the area present a non-carcinogenic risk higher than the maximum allowed. The need of mitigation actions is confirmed for reducing potential risks to the health of infants. This should not lead to replace breastfeeding as an adequate measure, but to establish comprehensive policies aimed to reduce environmental and health inequities.El objetivo de este estudio fue evaluar el riesgo en la salud de lactantes de menos de un mes a 24 meses de edad por ingesta de leche materna con contenido de cadmio (Cd), mercurio (Hg) y plomo (Pb). Se cuantificó el riesgo de efectos no carcinogénicos (REN) usando modelación probabilística con el programa Crystal Ball®, siguiendo los lineamientos del modelo de la Agencia de Protección Ambiental de Estados Unidos (USEPA). El promedio de los niveles máximos medidos de Cd (8.87 μg/kg), Hg (20.88 μg/kg) y Pb (37.29 μg/kg) estuvo 5, 21 y 19 veces, respectivamente, por encima de los límites máximos permitidos por la Organización Mundial de la Salud. Con relación al riesgo, los valores asociados con el contenido de al menos uno de los metales en leche materna pudieran superar en cada lugar de muestreo y cada subgrupo de lactantes los límites máximos permitidos por la USEPA (REN ≥ 1). Se presentó la primera evidencia de contaminación por metales pesados en leche materna de mujeres que viven en la ribera del río Cauca. En casos aislados, los lactantes expuestos por ingesta de esta leche, exceden el consumo tolerable de dichos contaminantes. Tomando en cuenta el peor escenario, los niños de la zona presentan riesgo no cancerígeno superior al máximo permitido. Se confirma la necesidad de acciones de mitigación para reducir potenciales riesgos a la salud de los lactantes. Esto no debe conducir a la sustitución de la lactancia como medida adecuada, sino a establecer políticas integrales que disminuyan las inequidades ambientales y de salud
DETERMINACIÓN DE LA DISTRIBUCIÓN DE CONTAMINANTES EMERGENTES EN AGUA INTERSTICIAL EN SEDIMENTOS DE HUMEDAL MEDIANTE LA OPTIMIZACIÓN Y VALIDACIÓN DE UN MÉTODO ANALÍTICO
Get PDFThe present work shows the methodology (study of a method) for the analysis of four emerging pollutants. Each studied pollutant represents a family from emerging pollutants (an estrogenic compound, an antibacterial, a pharmaceutical and a fragrance). The method was optimized to be used in a complex environmental matrix such as sediment interstitial water of a wetland with high organic matter content. The extraction of the compounds was carried out by solid phase extraction technique and quantified by gas chromatography with mass spectrometry in single ion monitoring mode. The method was validated using the “Single Laboratory Method Validation Process” through the determination of the performance parameters of the method. The optimized method was applied to the analysis of sediment interstitial water from the canals of the periurban agricultural zone of Xochimilco, Mexico. This preliminary study showed that the sampling point close to the wastewater discharge area from the secondary treatment wastewater plant had the highest concentration of emerging pollutants. Also, an inversely proportional relationship was observed between the concentrations of ibuprofen and musk with the concentration of organic matter in the sediments. The optimization of the method and the ratification with sediment interstitial water samples from the wetland, showed the worthiness of the method for the evaluation of the presence and distribution of emerging pollutants.El presente trabajo muestra la metodología (estudio de un método) para el análisis de cuatro contaminantes emergentes. Cada contaminante emergente estudiado, representa a una familia de interés de los contaminantes emergentes (un compuesto estrogénico, uno antibacteriano, un fármaco ácido y una fragancia). El método se optimizó para ser utilizado en una matriz ambiental compleja, como el agua intersticial de sedimentos de un humedal con alto contenido de materia orgánica. La extracción de los compuestos se llevó a cabo mediante la técnica de extracción en fase sólida y se cuantificó mediante cromatografía de gases con espectrometría de masas en modo de monitorización de ion único. El método se ratificó utilizando el “Proceso de validación del método de laboratorio único” mediante la determinación de los parámetros de validación del método. El método optimizado se aplicó al análisis del agua intersticial de los sedimentos de los canales de la zona agrícola periurbana de Xochimilco, México. Este estudio preliminar mostró que el punto de muestreo cercano al área de descarga de aguas residuales de la planta de tratamiento de aguas residuales de tratamiento secundario tenía la mayor concentración de contaminantes emergentes. Además, se observó una relación inversamente proporcional entre las concentraciones de ibuprofeno y almizcle cetona y la concentración de materia orgánica en los sedimentos. La optimización del método y la ratificación con muestras de agua intersticial de sedimentos del humedal, mostraron su valor para la evaluación de la presencia y distribución de contaminantes emergentes.
REMOCIÓN DE CROMO TRIVALENTE EN AGUAS RESIDUALES DE CURTIEMBRES MEDIANTE UN PROCESO BIÓTICO-ABIÓTICO BASADO EN EL USO DE Yarrowia lipolytica y Candida fluviatilis
Get PDFTanneries are recognized for generating highly polluting toxic wastes, including chromium, a metal that receives great attention due to the negative effects on biota and humans. Despite the existence of different physical and chemical methods for its treatment, these are not well received due to the high costs and complexity of the technologies. In order to evaluate the removal capacity of trivalent chromium with microorganisms from wastewater from leather tanning, acidophilic, chromium-resistant microorganisms were isolated in culture media prepared from the salts required for the tanning process. Subsequently, two native yeasts were selected, by their greater abundance, identified as Yarrowia lipolytica and Candida fluviatilis, which were used together to inoculate the batch type biotreatments, which consisted of Erlenmeyer flasks, packed with sand of 2.5 to 6 mm thick, containing tanning water at a concentration of 1021 mg Cr (III) / L, chemical, physical and biological controls were included. After 21 days of incubation, 97.5 % of the chromium was removed in the biotreatments, with an increase in pH. This research demonstrated the importance of the interaction of biotic and abiotic factors to enhance the removal of chromium in acid waters from tanneries. The results are novel for the treatment of tanning effluents, reducing the concentration of trivalent chromium by a biological method that in turn increases the pH, reaching permissible values and taking advantage of the own biodiversity of these effluents, benefits that make possible their later utility on a larger scale.Las curtiembres son reconocidas por generar residuos tóxicos altamente contaminantes, entre ellos el cromo, metal que recibe gran atención por los efectos negativos sobre la biota y los seres humanos. A pesar de existir diferentes métodos físicos y químicos para su tratamiento, son poco acogidos por los altos costos y la complejidad de las tecnologías. Con el propósito de evaluar la capacidad de remoción de cromo trivalente con microorganismos provenientes de aguas residuales del curtido de pieles, se aislaron microrganismos acidófilos, cromo resistentes, en medios de cultivo preparados a partir de las sales requeridas para el proceso del curtido. Posteriormente, se seleccionaron dos levaduras nativas, por su mayor abundancia, identificadas como Yarrowia lipolytica y Candida fluviatilis, que fueron utilizadas en conjunto para inocular los biotratamientos tipo lote, que se hicieron en matraces Erlenmeyer empacados con arena de 2.5 a 6 mm de grosor, que contenían agua del curtido, a una concentración de 1021 mg Cr (III)/L. Se incluyeron testigos químicos, físicos y biológicos. Después de 21 días de incubación en los biotratamientos se removió 97.5 % del cromo con aumento del pH. Esta investigación demostró la importancia de la interacción de factores bióticos y abióticos para potenciar la remoción del cromo en aguas ácidas provenientes de curtiembres. Los resultados son novedosos para el tratamiento de efluentes del curtido, al disminuirse la concentración de cromo trivalente mediante un método biológico que a su vez aumenta el pH, alcanzando valores permisibles y aprovechando la biodiversidad propia de estos efluentes, beneficios que posibilitan su posterior utilidad a mayor escala
ESTIMATING THE CHANGE OF VEGETATION COVERAGE OF THE UPSTREAM OF MINJIANG RIVER BY USING REMOTE-SENSING IMAGES
Get PDFThe upstream of Minjiang River, which was one of the main water sources for Chengdu Plain and the Yangtze River, was selected as the study area in the paper. With a series of cloud-free Landsat TM/OLI images acquired on June 24, 1994 and June 1, 2014, the vegetation coverage of the study area was calculated based on the vegetation index and dimidiate pixel model. The temporal and spatial changes of vegetation coverage were analyzed with digital elevation model and county area. The average vegetation coverage of the study area was decreased from 68.97% in 1994 to 60.39% in 2014. The analysis results showed that vegetation changes were closely related to topographical characteristics. The proportion of vegetation degradation area increased with the elevation increase and vegetation degradation was the most serious at the elevation range from 3500 m to 4500 m. The vegetation degeneration was the most obvious in Wenchuan County and Songpan County. Geological hazards caused by the earthquake and human disturbance were the main cause of the vegetation degradation and the aridity trend in the study area was another important factor. The upstream of Minjiang River, which was one of the main water sources for Chengdu Plain and the Yangtze River, was selected as the study area in the paper. With a series of cloud-free Landsat TM/OLI images acquired on June 24, 1994 and June 1, 2014, the vegetation coverage of the study area was calculated based on the vegetation index and dimidiate pixel model. The temporal and spatial changes of vegetation coverage were analyzed with digital elevation model and county area. The average vegetation coverage of the study area was decreased from 68.97% in 1994 to 60.39% in 2014. The analysis results showed that vegetation changes were closely related to topographical characteristics. The proportion of vegetation degradation area increased with the elevation increase and vegetation degradation was the most serious at the elevation range from 3500 m to 4500 m. The vegetation degeneration was the most obvious in Wenchuan County and Songpan County. Geological hazards caused by the earthquake and human disturbance were the main cause of the vegetation degradation and the aridity trend in the study area was another important factor.
THE APPLICATION OF IMPROVED CUCKOO SEARCH IN CASCADE RESERVOIR POWER GENERATION OPTIMIZED OPERATION
Get PDFCuckoo algorithm based on random walk of Levy flight search mechanism leads to instability of solutions and a tendency to get trapped in local optimal solution. Based on the characteristics of the optimal operation of cascade reservoir power generation, the paper proposes an improved cuckoo algorithm that features a new neighbour sequence algorithm for global search and a variable neighbourhood descent algorithm for local search, and applies the improved cuckoo algorithm to optimizing the operation of cascade reservoir power generation. Through case study, the paper proves the reasonability and reliability of the hybrid algorithm, and that the improved cuckoo algorithm provides more efficient and stable solutions, representing a new exploration about the optimal scheduling model for high-dimensional and complex cascade reservoirs power generation and operation.Cuckoo algorithm based on random walk of Levy flight search mechanism leads to instability of solutions and a tendency to get trapped in local optimal solution. Based on the characteristics of the optimal operation of cascade reservoir power generation, the paper proposes an improved cuckoo algorithm that features a new neighbour sequence algorithm for global search and a variable neighbourhood descent algorithm for local search, and applies the improved cuckoo algorithm to optimizing the operation of cascade reservoir power generation. Through case study, the paper proves the reasonability and reliability of the hybrid algorithm, and that the improved cuckoo algorithm provides more efficient and stable solutions, representing a new exploration about the optimal scheduling model for high-dimensional and complex cascade reservoirs power generation and operation. The original cuckoo search with the search mechanism of Lévy flight for a random walk has the defect of instability of the solution and trapping in local optimal solution. The paper applies cuckoo search to the optimal power generation of cascade reservoir by hybridizing it with new neighbour sequence algorithm global search and variable neighbourhood descent local search for enhancing the quality of the obtained solution combining of the characteristics of the optimal power generation of cascade reservoir. An example in the paper reveals that the results of the hybrid algorithm is rational and reliable when it is used to solve the problem of optimal operation of cascade reservoirs. The improved Cuckoo Search has been proved to be more efficient in optimization in terms of search efficiency and stability of the optimal results, whereby a new way for searching the solution to the optimal operation of cascade reservoirs with high dimension and complexity is provided
EVALUATION OF COMPLIANCE WITH REGULATORY FACTORS OF WASTE DISPOSAL SITES BY USING GEOGRAPHICAL INFORMATION SYSTEMS, CASE OF STUDY: STATE OF MEXICO
Get PDFCurrently, the State of Mexico (SM), the most densely populated Mexican State generates more than 19 000 t/d of municipal solid waste (MSW), which is disposed in waste disposal sites (WDS). Therefore, landfill siting should consider territorial issues and legal framework to minimize negative impacts. However, the inadequate record and management at WDS makes it difficult to get precise data related to volumes, sources and composition of MSW disposed, as well as to estimate leachate and biogas emissions. The aim of this work was to determine the status of WDS in the SM, by applying a methodological approach based on the analysis of WDS location, waste handling, disposal practices, general operations, as well as the emission of biogas and leachate. Cartography of the area and geographical information systems (GIS) technology were used to generate spatial data for sites assessment, taking into account the factors and risk parameters for the operation of the WDS. Applying the assessment methodology to 83 WDS of the SM, it was determined the current situation of sites location regarding the distances from landfill location to restricted areas and their compliance with federal and state regulations established in Mexico. The findings of this study show that although the few sites properly managed as landfills receive the higher amount of waste, the vast majority of the studied sites in the SM operate improperly, generating biogas and leachate, which impact negatively on water, groundwater, air, soil and probably human health. Currently, the State of Mexico (SM), the most densely populated Mexican State generates more than 19 000 t/d of municipal solid waste (MSW), which is disposed in waste disposal sites (WDS). Therefore, landfill siting should consider territorial issues and legal framework to minimize negative impacts. However, the inadequate record and management at WDS makes it difficult to get precise data related to volumes, sources and composition of MSW disposed, as well as to estimate leachate and biogas emissions. The aim of this work was to determine the status of WDS in the SM, by applying a methodological approach based on the analysis of WDS location, waste handling, disposal practices, general operations, as well as the emission of biogas and leachate. Cartography of the area and geographical information systems (GIS) technology were used to generate spatial data for sites assessment, taking into account the factors and risk parameters for the operation of the WDS. Applying the assessment methodology to 83 WDS of the SM, it was determined the current situation of sites location regarding the distances from landfill location to restricted areas and their compliance with federal and state regulations established in Mexico. The findings of this study show that although the few sites properly managed as landfills receive the higher amount of waste, the vast majority of the studied sites in the SM operate improperly, generating biogas and leachate, which impact negatively on water, groundwater, air, soil and probably human health
EFECTO DEL PRETRATAMIENTO HIDROTÉRMICO (ALTA PRESIÓN) E HIDROLISIS ENZIMÁTICA DE CLADODIOS DE Opuntia ficus-indica SOBRE LA LIBERACIÓN DE AZÚCARES Y SU USO POTENCIAL EN LA PRODUCCIÓN DE BIOETANOL
Get PDFThe production of second-generation biofuels requires raw materials that meet certain characteristics, among which stand out availability, price, fast growth, easy manipulation, among others. Opuntia ficus-indica was analyzed in this work given its wide world distribution, tolerance to extreme environments of drought and temperature, as well as its high yield as a crop. In addition, in times of pruning, the cladodes are abandoned on the site generating pollution problems so it is necessary to generate usage proposals. The production of bioethanol from cactus cladodes has been previously proposed but a hydrothermal pretreatment (HTP) in a high-pressure reactor (HPR) has not been applied. The use of high pressures is a method used with relative success in the pretreatment of other lignocellulosic substrates. In this work, the effect of temperature (150, 175, 185 and 205 º C), the addition of H2SO4 (0, 0.5, 1, 1.5 and 2 %) and the residence time in a HPR (1, 5 and 15 min) was studied. The solid residue obtained in the HTP was subjected to an enzymatic treatment to improve high-pressure hydrolysis of this raw material; finally, an alcoholic fermentation was carried out with Saccharomyces cerevisiae. The results showed significant time saving by applying a HTP compared to a conventional pretreatment (carried out in autoclaves). A final hydrolysis of 70.4 % of the nopal cladodes (combination of thermal pretreatment and enzymatic hydrolysis) and bioethanol production of 6.6 g/L were achieved.La producción de biocombustibles de segunda generación requiere de materias primas que reúnan ciertas características, entre las que destacan disponibilidad, precio, rápido crecimiento, fácil manipulación, entre otras. Opuntia ficus-indica fue analizada en este trabajo dada su amplia distribución en México, tolerancia a ambientes extremos de sequía y temperatura, así como su alto rendimiento como cultivo; aunado a esto, en periodos de poda, los cladodios son abandonados en el sitio generando problemas de contaminación por lo que es necesario generar propuestas de aprovechamiento. Se utilizaron cladodios de nopal como materia prima para la producción de etanol, utilizando un pretratamiento hidrótérmico (PTH) en un reactor de alta presión (RAP) para favorecer la hidrólisis de mucílago y fibras. Se estudió el efecto de la temperatura (150, 175, 185 y 205 ºC), la adición de H2SO4 (0, 0.5, 1, 1.5 y 2 %) y el tiempo de residencia en el RAP (1, 5 y 15 min). El residuo sólido obtenido del PTH fue sometido a un tratamiento enzimático, a fin de mejorar la hidrólisis y aprovechar en su totalidad esta materia prima. Finalmente se realizó una fermentación alcohólica con Saccharomyces cerevisiae. En los resultados obtenidos destaca el ahorro de tiempo por la aplicación del PTH en comparación con el pretratamiento tradicional, alcanzándose una hidrólisis final del 70.4 % de los cladodios de nopal (combinación de los pretratamiento térmico e hidrólisis enzimática) y una producción de bioetanol de 6.6 g/L