Revista Internacional de Contaminación Ambiental
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CHARACTERIZATION OF A Microbacterium sp. STRAIN ISOLATED FROM SOILS CONTAMINATED WITH HYDROCARBONS IN THE BURGOS BASIN, MEXICO
Get PDFThe development of novel bioremediation strategies has focused on the isolation and identification of microorganisms that can thrive in polluted environments to evaluate their potential as biotechnological tools in bioremediation techniques. In this work, a bacterium isolated from hydrocarbon-contaminated soils from the Burgos basin was identified and its hydrocarbon degradation potential was evaluated. Identification based on sequencing the 16S rRNA gene identified one of the isolates (R3) as Microbacterium petrolearium. This strain was mainly antibiotic-sensitive with elevated carbohydrate assimilation differing from previously reported strains. Moderate surfactant production (I24 = 22.97 %) was observed, which was absent in a cell-free extract. M. petrolearium R3 showed increased growth that correlated with pollutant concentration. For light crude oil, at a higher contaminant percentage, the R3 strain showed increased growth; however, in the case of diesel, no growth was detected. The aforementioned data indicate that M. petrolearium strain R3, isolated from local sources, has potential use as a tool for hydrocarbon-contaminated soil bioremediation
ESTIMACIÓN DEL BIOGÁS GENERADO EN SITIOS DE DISPOSICIÓN FINAL DEL ESTADO DE MÉXICO
Get PDFCurrently, the specific information on the management of most of the final disposal sites (FDS) in Mexico is unknown, as well as the volumes of biogas produced by the natural degradation of the organic matter contained in the disposed municipal solid waste (MSW). Biogas is mainly composed of methane and carbon dioxide, both considered greenhouse gases (GHGs). Several models have been developed for the calculation of GHG emissions from FDS, among which the Mexican Biogas Model 2.0 (MBM) and the Intergovernmental Panel on Climate Change model can be found. The aim of the present work was to estimate the amount of biogas generated in FDS of the State of Mexico by using the aforementioned models, to project the generation of biogas for a period of 50 years since the opening of the sites. To this aim, 30 FDS located in the SM comprised in a 50 km radius from the center of Mexico City were identified and data collected through visits and interviews were entered into the model’s spreadsheet. The annual generation of biogas was estimated for 15 landfills, six controlled sites and nine uncontrolled sites, classified according to the Official Mexican Standard NOM-083-SEMARNAT-2003. Biogas generation was calculated for the studied sites as 198 kt CH4 in 2017, 193 kt CH4 in 2020, 85 kt CH4 in 2030, and 12 kt CH4 for 2050. The results were used to evaluate their possible environmental impact in Mexico City and the adjacent municipalities.En México se desconoce la información sobre el manejo de la mayoría de los sitios de disposición final (SDF), al igual que las cantidades de biogás producidas por la degradación natural de materia orgánica contenida en los residuos sólidos urbanos eliminados. El biogás está compuesto principalmente por metano y dióxido de carbono, ambos considerados gases de efecto invernadero (GEI). Existen varios modelos para el cálculo de emisiones de GEI provenientes de SDF, entre los que encuentran el Modelo Mexicano de Biogás 2.0 (MMB) y el modelo del Grupo Intergubernamental de Expertos sobre el Cambio Climático. El objetivo del presente trabajo fue estimar la cantidad de biogás generada en SDF del estado de México (EM) utilizando ambos modelos, con el objetivo de proyectar la generación para un periodo de 50 años desde la apertura de los sitios. Con este fin se identificaron 30 SDF del EM en un radio de 50 km desde el centro de la ciudad de México y se recabó información mediante visitas y entrevistas para alimentar la hoja de cálculo de los modelos. Se calculó la generación anual de biogás para 15 rellenos sanitarios, seis sitios controlados y nueve sitios no controlados (clasificados de acuerdo con la Norma Oficial Mexicana NOM-083-SEMARNAT-2003). Se estimó una generación de biogás para los sitios de estudio de 198 kt de CH4 para 2017, 193 kt para 2020, 85 kt para 2030 y 12 kt de CH4 para 2050 con el MMB. Los resultados se utilizaron para evaluar su posible impacto en el ambiente de la Ciudad de México y municipios contiguos
EVALUACIÓN ECONÓMICA DE EVAPORACIÓN DE SALMUERAS DE ÓSMOSIS INVERSA: GESTIÓN AMBIENTAL EN MÉXICO
Get PDFReverse osmosis desalination is one of the most widely used technologies to reduce global water shortages. However, it presents environmental impacts from brine effluents that do not receive prior treatment at their disposal. The objective of this study is to evaluate the evaporation of brine discharges from desalination processes in brackish water (26 816 mg/L total dissolved solids [TDS]) and seawater (55 648 mg / L TDS) using electrical and thermal energy as a source of heat. The system was optimal when it presented higher salt removal (97 %) and evaporation rate (3.373 L/d), as well as lower energy consumption (5.43 kWh) and operating cost (703 016.00 MXN with a return of investment of 20%, recovery time of 10 years, and product water cost of 8.54 MXN/d), con un nivel de significancia de p = 0.05. El escalamiento del sistema eléctrico a un sistema térmico de destilación instantánea multietapa presenta una inversión de 37.37 MXN/m3. Los sistemas de evaporación de salmuera son socialmente eficientes para la disminución de problemáticas ambientales y económicas provocadas por el manejo inadecuado de efluentes de salmueras
HEALTH RISK DUE TO HEAVY METAL(LOID)S EXPOSURE THROUGH FINE PARTICULATE MATTER AND SEDIMENTED DUST IN PEOPLE LIVING NEXT TO A BEACH CONTAMINATED BY MINE TAILINGS
Get PDFThe non-carcinogenic hazard index (HI) and the carcinogenic risk index (CRI) due to exposure to metal(loid)s were assessed in children and adults living adjacent to a beach contaminated with mine tailings. Chromium (Cr), nickel (Ni), cadmium (Cd), arsenic (As), zinc (Zn), copper (Cu), lead (Pb) and manganese (Mn) were determined in fine particulate matter (PM2.5) and sedimented dust (SD) in school and residential microenvironments. The HI in children was 13.8, 8.1, 5.4, 2.4, 2.3 and 1.8-times greater than the safety threshold (1.0) for Cr, As, Pb, Mn, Cu, and Cd, respectively; 84.1 % explained by dermal contact and 10.9 % by ingestion of SD. The CRI for Cr and As was 3.7 and 3.2 times above the acceptable risk (> 1 × 10–4), explained by the inhalation of PM2.5 and SD, respectively. In adults, the CRI for As and Cr was 46.0 and 2.8 times greater than 1 × 10–4; As risk is explained by dermal contact and inhalation of SD, and Cr by inhalation of PM2.5. This study reports a high risk of potential adverse health effects on children and adults due to exposure to these elements present in the particles and dust studied.The non-carcinogenic hazard index (HI) and the carcinogenic risk index (CRI) due to exposure to metal(loid)s were assessed in children and adults living adjacent to a beach contaminated with mine tailings. Chromium (Cr), nickel (Ni), cadmium (Cd), arsenic (As), zinc (Zn), copper (Cu), lead (Pb) and manganese (Mn) were determined in fine particulate matter (PM2.5) and sedimented dust (SD) in school and residential microenvironments. The HI in children was 13.8, 8.1, 5.4, 2.4, 2.3 and 1.8-times greater than the safety threshold (1.0) for Cr, As, Pb, Mn, Cu, and Cd, respectively; 84.1 % explained by dermal contact and 10.9 % by ingestion of SD. The CRI for Cr and As was 3.7 and 3.2 times above the acceptable risk (> 1 × 10–4), explained by the inhalation of PM2.5 and SD, respectively. In adults, the CRI for As and Cr was 46.0 and 2.8 times greater than 1 × 10–4; As risk is explained by dermal contact and inhalation of SD, and Cr by inhalation of PM2.5. This study reports a high risk of potential adverse health effects on children and adults due to exposure to these elements present in the particles and dust studied
REGISTRO PRELIMINAR DE MICROPLÁSTICOS EN FECAS DEL LEÓN MARINO SUDAMERICANO (Otaria byronia [de Blainville 1820]) RECOLECTADAS EN PUNTA SAN JUAN, PERÚ
Get PDFPlastic waste has been identified in otariid excreta around the world. However, in Peru, previous reports of these contaminants in O. byronia have not been evaluated. In this study, we report the presence and shapes of microplastics (MPs) found in scat samples of this species, collected within a natural protected area in southern Peru. A total of 47 plastic particles classified as fibers and fragments were identified, whose average length was 3.02 and 1.19, respectively. The origin of these millimetric plastic particles in O. byronia scats is unknown; however, other studies have associated the incidence of MPs to the diet of the animals. For future studies, we suggest improving the detection techniques of MPs to continue research efforts on contaminants in free ranging aquatic species.Los residuos plásticos han sido identificados en excretas de otáridos alrededor del mundo. No obstante, en el Perú los reportes previos de estos contaminantes en Otaria byronia no han sido evaluados. En el presente trabajo se reporta la presencia y forma de microplásticos (MP) en las heces de esta especie, recolectadas dentro de un área natural protegida al sur del Perú. Se logró identificar un total de 47 partículas plásticas clasificadas como fibras y fragmentos, cuya media longitudinal fue de 3.02 y 1.19 mm, respectivamente. La procedencia de estas partículas plásticas milimétricas en las fecas de O. byronia se desconoce; sin embargo, otros estudios han asociado la incidencia de MP en la dieta de los animales. Se sugiere mejorar las técnicas de detección de MP en futuros estudios para continuar los esfuerzos de investigación de contaminantes en animales silvestres marinos
MULTI-CRITERIA ASSESSMENT MODEL TO IDENTIFY SUITABLE AREAS FOR TREATED WASTEWATER REUSE IN AGRICULTURE
Get PDFA model of land suitability analysis for irrigation with treated domestic wastewater is presented. The model integrates tools of Multi-Criteria Evaluation with Geographical Information Systems. Several criteria were selected to adapt the model to the conditions and characteristics of the case study. The adaptation process included field visits, a bibliographical review, and personal interviews with local actors and experts. Six constraints and 10 factors were selected and 3158 hectares suitable for the activity were identified. The areas were classified into three categories of aptitude, representing high fitness sites close to the current wastewater treatment plant. The developed tool allowed us to integrate different criteria to assess site suitability for wastewater reuse, with the advantage that the tool can be adapted to other regions and/or objectives.A model of land suitability analysis for irrigation with treated domestic wastewater is presented. The model integrates tools of Multi-Criteria Evaluation with Geographical Information Systems. Several criteria were selected to adapt the model to the conditions and characteristics of the case study. The adaptation process included field visits, a bibliographical review, and personal interviews with local actors and experts. Six constraints and 10 factors were selected and 3158 hectares suitable for the activity were identified. The areas were classified into three categories of aptitude, representing high fitness sites close to the current wastewater treatment plant. The developed tool allowed us to integrate different criteria to assess site suitability for wastewater reuse, with the advantage that the tool can be adapted to other regions and/or objectives
EFECTO DE LAS ZEOLITAS SOBRE CIERTAS PROPIEDADES DE UN SUELO ENMENDADO CON BIOSÓLIDOS
Get PDFThe application of biosolids as an organic amendment in degraded soils constitutes an alternative of disposal; however, they may contain varying concentrations of potentially toxic trace elements (PTE) that accumulate in soils and may alter microbial activity. Zeolites are minerals that have porous spaces and internal channels with a high cation-exchange capacity. The objective of this work was to determine the influence of the addition of zeolites on the microbial activity, pH, electrical conductivity (EC), oxidizable carbon and phosphorus availability (P) in a soil amended with biosolids. An incubation experiment was carried out at room temperature. The incorporation of zeolites did not significantly modify the microbial activity of the non-amended or biosolids amended soils. However, zeolites significantly increased the pH (by 2.89 and 1.18) and EC (by 4374 and 1459 µS/cm) in the non-amended or biosolids amended soils and produced a significant reduction in the concentration of extractable phosphorus. In view of the increase in pH and EC values observed, the proportion of biosolids and zeolites or the use of supplementary irrigation should be carefully evaluated when these amendments are incorporated together, to avoid soil salinization if the objective is to use them for soil restoration.La aplicación de biosólidos como enmienda orgánica para restaurar suelos degradados constituye una alternativa para su eliminación. Sin embargo, los biosólidos pueden presentar concentraciones variables de elementos traza potencialmente tóxicos (EPT) que se acumulan en los suelos alterando la actividad microbiana. Las zeolitas son minerales que tienen espacios porosos y canales internos con una elevada capacidad de intercambio catiónico. El objetivo de este trabajo fue determinar la influencia del agregado de zeolitas sobre la actividad microbiana, pH, conductividad eléctrica (CE), carbono oxidable y disponibilidad de fósforo (P) en un suelo remediado con biosólidos. Se realizó un ensayo de incubación a temperatura ambiente. Se observó que la incorporación de zeolitas no modificó significativamente la actividad microbiana de los suelos sin remediar o remediados con biosólidos; sin embargo, incrementó de manera importante los valores de pH (en 2.89 y 1.18 unidades) y CE (en 4374 y 1459 µS/cm) en los suelos sin enmendar o enmendados con biosólidos, y produjo una reducción significativa en la concentración de fósforo extraíble. Dado el incremento en los valores de pH y CE observados, la proporción de biosólidos y zeolitas o el empleo de riego suplementario deben evaluarse cuidadosamente cuando estas remediaciones se incorporan de forma conjunta en el suelo, para evitar salinización si el objetivo es emplear ambas remediaciones de manera conjunta con fines de restauración de suelos
STABILIZATION OF LEACHATE IN AGGREGATES MADE WITH PLASTIC FROM WEEE
Get PDFA recycled plastic aggregate (RPA) was developed using the core-shell strategy, where the core is the plastic fraction of Waste of Electrical and Electronic Equipment (WEEE) and a cement matrix with stabilizing additives acts as the shell. The amount of brominated flame retardant (mainly tetrabromobisphenol-A) leached in curing water of RPAs was quantified using extraction with an organic solvent and gas chromatography methods (CG-FID). A clear relationship can be established between the characteristics of the stabilizing additive used and the amount of tetrabromobisphenol-A and bisphenol-A leached. The additive used was activated carbon, which in a manufacture scale may be provided by different suppliers with different mesoporous characteristics, which can be easily determined by the iodine number. The analysis proposed can be an effective way to determine if a particular activated carbon can be used as stabilizing additive in the production of RPAs with the developed technology.A recycled plastic aggregate (RPA) was developed using the core-shell strategy, where the core is the plastic fraction of Waste of Electrical and Electronic Equipment (WEEE) and a cement matrix with stabilizing additives acts as the shell. The amount of brominated flame retardant (mainly tetrabromobisphenol-A) leached in curing water of RPAs was quantified using extraction with an organic solvent and gas chromatography methods (CG-FID). A clear relationship can be established between the characteristics of the stabilizing additive used and the amount of tetrabromobisphenol-A and bisphenol-A leached. The additive used was activated carbon, which in a manufacture scale may be provided by different suppliers with different mesoporous characteristics, which can be easily determined by the iodine number. The analysis proposed can be an effective way to determine if a particular activated carbon can be used as stabilizing additive in the production of RPAs with the developed technology
BIOMONITORING OF A POPULATION RESIDING NEAR TO MINE TAILINGS IN GUANAJUATO, MEXICO
Get PDFSome metals present in residues coming from mining activities can damage DNA. A preliminary evaluation was carried out to determine the genotoxic effects on a resident population from a mining area in Xichú, Guanajuato, Mexico. Blood lead levels (BLL), and arsenic levels in urine (AsU), were measured as biomarkers of exposure. Hematological damage was evaluated trough hematocrit, hemoglobin and activity of enzyme delta-aminolevulinic dehydratase (δ-ALAD). DNA damage in blood cells was evaluated by comet assay. BLL (7.5 ± 1.2 and 7.9 ± 3.3 μg/dL) and AsU (25.2 ± 15.8 and 18.3 ± 18.4 μg/g creatinine) were found in children and adults, respectively. Of the children and adults, 100 and 91.7 %, respectively had levels of enzyme activity below 20 U/L erythrocytes. Regarding DNA damage, the children showed an Olive tail moment of 5.0 ± 1.6 and a tail length of 40.9 ± 4.9 μm, of similar magnitude than adults (4.6 ± 1.0 and 41.8 ± 5.9 μm, respectively). In conclusion, this preliminary study describes the health risk scenario of population near the mine, nevertheless, more studies are needed in the area.Some metals present in residues coming from mining activities can damage DNA. A preliminary evaluation was carried out to determine the genotoxic effects on a resident population from a mining area in Xichú, Guanajuato, Mexico. Blood lead levels (BLL), and arsenic levels in urine (AsU), were measured as biomarkers of exposure. Hematological damage was evaluated trough hematocrit, hemoglobin and activity of enzyme delta-aminolevulinic dehydratase (δ-ALAD). DNA damage in blood cells was evaluated by comet assay. BLL (7.5 ± 1.2 and 7.9 ± 3.3 μg/dL) and AsU (25.2 ± 15.8 and 18.3 ± 18.4 μg/g creatinine) were found in children and adults, respectively. Of the children and adults, 100 and 91.7 %, respectively had levels of enzyme activity below 20 U/L erythrocytes. Regarding DNA damage, the children showed an Olive tail moment of 5.0 ± 1.6 and a tail length of 40.9 ± 4.9 μm, of similar magnitude than adults (4.6 ± 1.0 and 41.8 ± 5.9 μm, respectively). In conclusion, this preliminary study describes the health risk scenario of population near the mine, nevertheless, more studies are needed in the area
ACID RESIDUES REMEDIATION FROM MINES USING BIOCHAR, MONOPOTASSIUM PHOSPHATE AND LIME
Get PDFThe Zimapán mining district in the state of Hidalgo (Mexico) generates residues with high content of Cu, Pb and Zn which have been disposed for decades on sites that could cause toxicity to the surrounding area. Simultaneously, district’s water dams have been affected by an invasive plant called water hyacinth (Eichhornia crassipes), both of problems require attention and remediation treatments. The objectives of this research were: a) to evaluate biochar derived from water hyacinth (H) in mining acid residues; and b) to compare its performance vs monopotassium phosphate (F), lime (L) and the phosphates mixtures with biochar (FH) or with lime (FL) by a bioassay of barley root growth, soluble metal and pH. In this investigation four substrates was used to emulate pollution gradients: 100 %-neutral pristine soil (M1); 100 %-acid mine residues (M4); and two mixtures soil: residues (w/w) of 65:35 (M2) and 35:65 (M3). The substrates were treated with the amendment (dose w/w): H (10 %-substrate), L (3.4 %-residues), F (0.06 %-soil + 0.6 %-residues), FH (0.06 %-soil + 0.6 %-residues + 10 %-substrate) y FL (0.06 %-soil + 0.6 %-residues + 3.4 %-residues) (22 total-treatments, blanks-included). This study shows that water hyacinth could be utilized as an acid mine residues treatment by converting it to biochar. It caused the increase of root length, pH and reduce the soluble Cu and Zn as with the others amendments when the residues were present. Although the reduction of soluble Pb with biochar was considerably lower than with lime in the residues-substrates. The Zimapán mining district in the state of Hidalgo (Mexico) generates residues with high content of Cu, Pb and Zn which have been disposed for decades on sites that could cause toxicity to the surrounding area. Simultaneously, district’s water dams have been affected by an invasive plant called water hyacinth (Eichhornia crassipes), both of problems require attention and remediation treatments. The objectives of this research were: a) to evaluate biochar derived from water hyacinth (H) in mining acid residues; and b) to compare its performance vs monopotassium phosphate (F), lime (L) and the phosphates mixtures with biochar (FH) or with lime (FL) by a bioassay of barley root growth, soluble metal and pH. In this investigation four substrates was used to emulate pollution gradients: 100 %-neutral pristine soil (M1); 100 %-acid mine residues (M4); and two mixtures soil: residues (w/w) of 65:35 (M2) and 35:65 (M3). The substrates were treated with the amendment (dose w/w): H (10 %-substrate), L (3.4 %-residues), F (0.06 %-soil + 0.6 %-residues), FH (0.06 %-soil + 0.6 %-residues + 10 %-substrate) y FL (0.06 %-soil + 0.6 %-residues + 3.4 %-residues) (22 total-treatments, blanks-included). This study shows that water hyacinth could be utilized as an acid mine residues treatment by converting it to biochar. It caused the increase of root length, pH and reduce the soluble Cu and Zn as with the others amendments when the residues were present. Although the reduction of soluble Pb with biochar was considerably lower than with lime in the residues-substrates.