Revista Internacional de Contaminación Ambiental
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BACTERIAL MICROBIOTA FROM WILD FRESHWATER FISH UTILIZED FOR SUBSISTENCE IN WESTERN MEXICO
Get PDFMicrobiological analyses of freshwater fish utilized in subsistence fisheries are relatively scarce. These fisheries are widespread throughout Latin America, and support numerous communities in rural, impoverished areas. We present the results of genetically-based microbiological analyses of river water samples and fish tissue samples obtained from specimens (n = 128) captured in the wild from three sites in the Ayuquila river, west central Mexico. The system is affected by numerous human activities. We identify 11 bacterial taxa of which Pseudomonas stutzeri, Shigella sonnei, Escherichia coli and Bacillus subtilis were isolated from the most fish. Citrobacter freundii and E. coli were present in water samples from all sites. Average taxa richness was similar among rainy and dry seasons. Enterobacteriaceae dominate the bacterial microbiota of water and fishes of the Ayuquila river, suggesting there is significant influence from anthropic activities in the basin. Our findings provide a baseline upon which to improve our understanding of the microbiology of the Ayuquila river and similar systems in west central Mexico, especially related to risks for biota and human populations dependent on rivers for sustenance.Microbiological analyses of freshwater fish utilized in subsistence fisheries are relatively scarce. These fisheries are widespread throughout Latin America, and support numerous communities in rural, impoverished areas. We present the results of genetically-based microbiological analyses of river water samples and fish tissue samples obtained from specimens (n = 128) captured in the wild from three sites in the Ayuquila river, west central Mexico. The system is affected by numerous human activities. We identify 11 bacterial taxa of which Pseudomonas stutzeri, Shigella sonnei, Escherichia coli and Bacillus subtilis were isolated from the most fish. Citrobacter freundii and E. coli were present in water samples from all sites. Average taxa richness was similar among rainy and dry seasons. Enterobacteriaceae dominate the bacterial microbiota of water and fishes of the Ayuquila river, suggesting there is significant influence from anthropic activities in the basin. Our findings provide a baseline upon which to improve our understanding of the microbiology of the Ayuquila river and similar systems in west central Mexico, especially related to risks for biota and human populations dependent on rivers for sustenance
EVALUACIÓN DEL IMPACTO EN LA SALUD POR PARTÍCULAS PM2.5 EN SINALOA, MÉXICO
Get PDFThere is a growing global interest in the evaluation of health effects generated by environmental pollution and its economic quantification. This article analyzes the health impacts caused by PM2.5 air pollution in the main cities of the state of Sinaloa, Mexico: Culiacán (capital), Mazatlán and Los Mochis, Ahome; it also estimates avoidable deaths if the concentration of contaminants was reduced to the levels recommended by the World Health Organization and the corresponding Official Mexican Standard, and monetizes the economic costs through the loss of productivity of associated deaths to PM2.5. It was found that avoidable total deaths would be 354 and 261 using the international and Mexican norms, respectively. The calculated economic cost of exceeding the permissible limits of PM2.5 in the main cities of Sinaloa was in the range of 24 to 34 million dollars for 2017. It is recommended to design local environmental policies that promote the reduction of PM2.5 levels, for which it is necessary to identify emissions by source type with the objective of implementing specific actions that, from a local perspective, contribute to the national goal of mitigating the negative impacts of air pollution.Existe un creciente interés a nivel internacional por evaluar los efectos en la salud que genera la contaminación ambiental y su cuantificación económica. Este artículo analiza los impactos en la salud que causa la contaminación del aire por PM2.5 en las principales ciudades del estado de Sinaloa, México: Culiacán (capital), Mazatlán y Los Mochis, Ahome; asimismo, estima las muertes que se evitarían si la concentración de la contaminación se redujera a los niveles recomendados por la Organización Mundial de la Salud y la Norma Oficial Mexicana correspondiente, y calcula los costos económicos debidos a pérdida de productividad de las muertes asociadas a PM2.5. Se encontró que las muertes totales evitables serían 354 y 261 utilizando la norma internacional y mexicana, respectivamente. El costo económico calculado por exceder los límites permisibles de PM2.5 en las principales ciudades de Sinaloa estuvo en el rango de 24 a 34 millones de dólares para 2017. Se recomienda diseñar políticas ambientales locales que promuevan la reducción de los niveles de PM2.5, para lo cual se requiere identificar las emisiones por tipo de fuente con el objetivo de implementar acciones específicas que, desde una perspectiva local, contribuyan a la meta nacional de mitigar los impactos negativos de la contaminación del aire
REMOVAL OF REACTIVE RED 120 IN AQUEOUS SOLUTION USING Mg-HYDROTALCITES AS ADSORBENTS SOLIDS: KINETICS AND ISOTHERMS
Get PDFReactive red 120 (RR120) is a widely used dye in the textile industry but its release in aqueous wastewater is a serious problem due to its toxicity and low biodegradability. The aim of this work was to evaluate the effect of the trivalent cation of magnesium-based materials type hydrotalcite as adsorbents applied to RR120 dye removal in aqueous solution. The samples were synthesized by continuous coprecipitation and were characterized by surface area measurements, X-ray diffraction and temperature-programmed desorption of CO2. Dye adsorption tests were carried out using different adsorbent dosages and contact time. The kinetic adsorption was studied for the pseudo-first and pseudo-second order models. The equilibrium adsorption data were fitted to the Langmuir, Freundlich and Redlich-Peterson isotherm models. The most suitable adsorption conditions were found at a residence time of 60 min and solid dosage of 2.5 g/Lfor HDL-MgFe, 2 g/L for HDL-MgAl and HC-Mg. The results showed that pseudo-second order model, as well as the Langmuir and Redlich-Peterson models best described the removal process. The Al containing compound presented the best results due to a better interaction between strength and number of basic sites.Reactive red 120 (RR120) is a widely used dye in the textile industry but its release in aqueous wastewater is a serious problem due to its toxicity and low biodegradability. The aim of this work was to evaluate the effect of the trivalent cation of magnesium-based materials type hydrotalcite as adsorbents applied to RR120 dye removal in aqueous solution. The samples were synthesized by continuous coprecipitation and were characterized by surface area measurements, X-ray diffraction and temperature-programmed desorption of CO2. Dye adsorption tests were carried out using different adsorbent dosages and contact time. The kinetic adsorption was studied for the pseudo-first and pseudo-second order models. The equilibrium adsorption data were fitted to the Langmuir, Freundlich and Redlich-Peterson isotherm models. The most suitable adsorption conditions were found at a residence time of 60 min and solid dosage of 2.5 g/Lfor HDL-MgFe, 2 g/L for HDL-MgAl and HC-Mg. The results showed that pseudo-second order model, as well as the Langmuir and Redlich-Peterson models best described the removal process. The Al containing compound presented the best results due to a better interaction between strength and number of basic sites
MODELACIÓN Y ESTIMACIÓN DE NO2 Y O3 EN ZONAS RURALES Y SUBURBANAS DEL VALLE DE MÉXICO
Get PDFForests surrounding the Valley of Mexico are affected by air pollution produced within the valley; however, air pollution monitoring stations are scarce within the forest areas. This condition prevents the impacts of air pollution on forests from being studied. The aim of this study was to investigate the technical feasibility of using mathematical models to estimate O3 and NO2 concentrations in rural and suburban sites around the Valley of Mexico. Models for estimation of O3 and NO2 from data collected from the stations of the Red Automática de Monitoreo Atmosférico (automatic air quality monitoring network, RAMA) and climatological variables from the Red de Meteorología y Radiación Solar (meteorology and solar radiation network, REDMET) of the Valley of Mexico were developed. We made 12 lineal multiple regression models for estimating air pollutants for stations Ajusco Medio, Cuajimalpa, Cuautitlán, and Montecillo. Estimations of O3 are a function of O3 concentrations and/or concentrations of NO2, O3, and meteorological variables from RAMA and REDMET. Models for NO2 estimate this pollutant as a function of concentrations of NO2 and meteorological variables. The best models for estimating O3 are those that depend on O3 concentrations from other stations, being temperature, relative humidity, and wind velocity the meteorological variables that impacted O3 estimations the most. Models for NO2 concentrations behaved correctly, except that of Cuautitlán. Temperature and wind direction are the variables that impacted NO2 concentrations the most.Los bosques circundantes del Valle de México son afectados por la contaminación del aire producida en el valle; sin embargo, en el bosque son escasas las estaciones de monitoreo ambiental. Esto dificulta el estudio de los impactos de la contaminación en esa área. El presente estudio pretendió investigar la factibilidad técnica del uso de modelos matemáticos para estimar la presencia de O3 y NO2 en puntos rurales y suburbanos del Valle de México. Se desarrollaron modelos de estimación de O3 y NO2 en áreas rurales y suburbanas del Valle de México, usando registros de las estaciones de la Red Automática de Monitoreo Atmosférico (RAMA) y de variables meteorológicas de la Red de Meteorología y Radiación Solar (REDMET) del Valle de México. Se elaboraron 12 modelos de regresión lineal múltiple para las estaciones de monitoreo Ajusco Medio, Cuajimalpa, Cuautitlán y Montecillo. Las estimaciones de O3 están en función de las concentraciones de dicha sustancia, o bien a partir de concentraciones de NO2, O3 y variables meteorológicas registradas por la RAMA y la REDMET. Los modelos para NO2 estiman el contaminante en función de concentraciones de NO2 y variables meteorológicas. Los mejores modelos de estimación de O3 son aquellos que dependen de sus concentraciones registradas en otras estaciones, mientras que las variables meteorológicas con mayor impacto sobre el O3 son temperatura, humedad relativa y velocidad del viento. Los modelos para el NO2 presentaron buen comportamiento excepto en la estación Cuautitlán. Las variables con mayor impacto sobre el NO2 son temperatura y dirección de vientos
PATOTIPOS Y RESISTENCIA A ANTIBIÓTICOS DE Escherichia coli EN AGUA RESIDUAL
Get PDFWater pollution is a serious environmental problem. We analyzed the presence of total fecal coliforms and Escherichia coli, the prevalence of diarrheal pathotypes, and the profiles of antibiotic resistance at different stages. Three composite samples from a wastewater treatment plant (WWTP) in Mexico were analyzed for the presence E. coli with the physical and chemical parameters established in the Mexican Official Standard NOM-001-SEMARNAT-1996. Fifty seven strains were selected from the different stages of the process, and the following pathotypes were determined by multiplex polymerase chain reaction: enteropathogenic (EPEC), enterotoxigenic (ETEC), enteroinvasive (EIEC), enteroaggregative (EAEC), enterohemorrhagic (EHEC), and diffuse adherence (DAEC). Their resistance was assessed by the Kirby Bauer method. The results showed a removal efficiency of 95.4% based on the chemical oxygen demand (BOD5). Coliforms and E. coli were found to be higher in the influent. The total frequency of pathotypes was 39 % (22/57) for EIEC, 30 % (17/57) for ETEC, and 15.5 % (9/57) for DAEC and EPEC. Regarding the distribution, 39% of ETEC was detected in the influent, 50% of EIEC before disinfection, 100% of EIEC after disinfection and 43% of ETEC in the effluent.La contaminación del agua es un problema ambiental grave. En una planta de tratamiento de agua residual (PTAR) en México se evaluó la presencia de coliformes fecales totales y de Escherichia coli, la prevalencia de patotipos diarreicos y los perfiles de resistencia a los antibióticos en las diferentes etapas del tratamiento. Se realizaron tres muestreos compuestos para evaluar la presencia de E. coli con los parámetros físicos y químicos establecidos en la Norma Oficial Mexicana NOM-001-SEMARNAT-1996. Se seleccionaron 57 cepas de las diferentes etapas del proceso y se determinó el patotipo de E. Coli por reacción en cadena de polimerasa múltiplex: enteropatógena (EPEC), enterotoxigénica (ETEC), enteroinvasiva (EIEC), enteroagregativa (EAEC), enterohemorrágica (EHEC) y de adherencia difusa (DAEC); asimismo, se determinó su resistencia por el método de Kirby Bauer. Los resultados muestran una eficiencia de remoción del 95.4 %,con base en la demanda química de oxígeno (DBO5). Los coliformes y E. coli son mayores en el influente. La frecuencia total de patotipos fue del 39 % (22/57) de EIEC, 30 % (17/57) de ETEC y 15.5 % (9/57) de DAEC y EPEC. Respecto de la distribución, se detectó un 39 % de ETEC en el influente, 50 % de EIEC antes de la desinfección, 100 % de EIEC después de la desinfección y un 43 % de ETEC en el efluente. Todas las cepas muestran baja resistencia a los antibióticos. La eficiencia de remoción de la PTAR, con base en el DBO5, es alta y cumple con las normas ambientales, sin embargo, la presencia de patotipos diarreicos en el efluente impacta negativamente al ambiente y a la salud pública
ESTUDIO INTEGRAL DE LA CALIDAD DEL AGUA EN EL LITORAL DEL PUERTO SAN CARLOS, BAJA CALIFORNIA SUR, MÉXICO
Get PDFPhysical, chemical and biological parameters were measured in March and November 2014. These water analyses were carried out at 22 sites on the coast of Puerto San Carlos (Magdalena Bay, Baja California Sur, Mexico), with the objective of assessing water quality and identifying possible sources of water pollution and its status according to Mexican regulations. The study area was divided into three zones according to its main activity: (1) thermoelectric power station, (2) fiscal port harbor and (3) San Carlos estuary, adjacent to the to the town of the same name. The measured physical, chemical and biological parameters were temperature, salinity, dissolved oxygen, chlorophyll-a, nutrients, dissolved trace metals, and coliform bacteria. The results showed poor water quality in the three areas studied, in accordance with NOM-001-SEMARNAT-1996 and the ecological criteria for water quality CE-CCA-001/89, in particular regarding phosphate, ammonium, and silicate (unregulated) concentrations, as well as the presence of Escherichia coli. The three zones are considered sources of anthropogenic contamination whose impact is greater in the warmest month and dead tides, probably due to the entry of water contaminated by anthropogenic waste derivatives. According to the sanitary authorities of the state of Baja California Sur, the certification of water quality in Magdalena Bay has been variable: it was not certified in 2014, whilst in the period 2015-2017 it was re-certified. Although this region is an important touristic and fishing site, it is at risk of contamination due to the lack of a wastewater treatment system in the town and the inadequate disposal of raw sewage from the port.En marzo y noviembre de 2014 se llevaron a cabo mediciones de parámetros físicos, químicos y biológicos del agua superficial en 22 sitios del litoral de Puerto San Carlos (Bahía Magdalena, Baja California Sur, México), con el objetivo de evaluar la calidad del agua, identificar las posibles fuentes de contaminación y su estatus de acuerdo con la reglamentación mexicana. El área de estudio fue dividida en tres zonas según su actividad principal: 1) central termoeléctrica, 2) muelle fiscal portuario y (3) estero San Carlos, aledaño al poblado del mismo nombre. Los parámetros físicos, químicos y biológicos medidos fueron: temperatura, salinidad, oxígeno disuelto, clorofila-a, nutrientes, metales traza disueltos y bacterias coliformes. Los resultados mostraron una mala calidad del agua en las tres zonas estudiadas, de acuerdo con la NOM-001-SEMARNAT-1996 y los Criterios Ecológicos de Calidad del Agua CE-CCA-001/89, en particular con relación a los niveles de fosfato, amonio, silicato (no reglamentado) y la presencia de Escherichia coli. Las tres zonas se consideran fuentes de contaminación y su impacto es mayor en el mes más cálido y en mareas muertas, debido probablemente a la entrada de aguas contaminadas con derivados de residuos antrópicos. De acuerdo con las autoridades sanitarias del estado de Baja California Sur, la certificación de calidad del agua en Bahía Magdalena ha sido variable: en 2014 no fue certificada, mientras que en el periodo 2015-2017 fue nuevamente certificada. Esta región, que constituye un importante sitio de aprovechamiento pesquero y turístico, se encuentra en riesgo de contaminación debido a la falta de un sistema de tratamiento de aguas residuales en el poblado y a la inadecuada disposición de aguas grises y negras del puerto
REMOCIÓN DE CONTAMINANTES DEL NEJAYOTE CON ALGINATO Y QUITOSANO
Get PDFNejayote is the residual water from the nixtamalization process characterized by an alkaline pH (pH > 10) as well as high concentrations of dissolved and suspendedorganic matter (COD > 10 200 mg/L). As for the above mentioned, nejayote is considered within the more pollutants liquid effluents discharged into different water bodies. In this work, the effectiveness of sodium alginate and chitosan to reduce nejayote pollutants was tested. The application of alginate involved adsorption and gelation, which trapped suspended and dissolved material, and the use of chitosan implied an adsorption-precipitation phenomena. These polymers were used separately and sequentially. In the independent treatments, the alginate was more efficient than the chitosan, obtaining a COD removal of 61.43 ± 0.24 % and of 59.74 ± 0.36 % respectively. In sequential treatments, the removal efficiency of COD with alginate-chitosan was higher (70.19 ± 0.85 %) than that of the chitosan-alginate treatment (67.21 ± 0.24 %). On the other hand, the reduction in the amount of total solids allows that the effluent, after the processing, is within the maximum permissible limit established by the official Mexican standards NOM-002-SEMARNAT-1996 and NOM-001-SEMARNAT-1996.,This permits its discharge to urban or municipal sewerage systems and it can even be used for agricultural irrigation. The use of these biodegradable polymers is a viable option that has the potential to scale at the industrial level, contributing to the purification of discharges from the nixtamalization industry and to the benefit of the environment.El nejayote es el agua residual proveniente del proceso de nixtamalización que se caracteriza por poseer un pH alcalino (pH > 10) así como altas concentraciones de materia orgánica disuelta y suspendida (DQO > 10 200 mg/L), por lo que se considera uno de los efluentes más contaminantes vertidos a diferentes cuerpos de agua. Se probó la efectividad del alginato de sodio y el quitosano para disminuir los contaminantes del nejayote. La aplicación de alginato de sodio involucró la adsorción y gelificación con la que se atrapó material suspendido y disuelto, y el uso del quitosano implicó adsorción y precipitación. Se realizó la aplicación de estos polímeros de manera separada y secuencial. En el tratamiento independiente, el alginato resultó más eficiente que el quitosano, obteniéndose una remoción de DQO de 61.43 ± 0.24 % y de 59.74 ± 0.36 %, respectivamente. En el tratamiento secuencial, la eficiencia de remoción de la DQO con el tratamiento alginato-quitosano resultó ser mayor (70.19 ± 0.85 %) que la del tratamiento quitosano-alginato (67.21 ± 0.24 %). Por su parte, la cantidad de sólidos totales presentes después del procesamiento se encuentra dentro del límite máximo permisible establecido en las normas oficiales mexicanas NOM-002-SEMARNAT-1996 y NOM-001-SEMARNAT-1996, permitiendo su descarga al sistema de alcantarillado urbano o municipal e incluso puede ser utilizada en suelo para riego agrícola. El uso de estos polímeros biodegradables es una opción viable que tiene potencial para escalarse a nivel industrial, contribuyendo a la depuración de descargas de la industria de la nixtamalización y en beneficio del ambiente.
FUNGICIDAL METHYL-2-BENZIMIDAZOLE CARBAMATE ADSORPTION IN SOIL AND REMEDIATION VIA Prunus dulcis DERIVED ACTIVATED CARBON
Get PDFCarbendazim (methyl-2-benzimidazole carbamate i.e. MBC) was investigated for pedospheric adsorption-desorption, mobility and effective removal via Prunus dulcis derived activated carbon in addition to physical and chemical characterization of selected soils. MBC was adsorbed into six agriculturally soils with distinctive characteristics via batch-equilibrium method and was evaluated via linear and Freundlich models. The highest value for linear and Freundlich adsorption coefficients i.e. Kd and Kf (8.8 µg/mL and 11 µg/mL respectively) corresponds to soil sample 6 having organic matter (3.3 %) and clay (18 %). Soils exhibited variable affinity towards MBC adsorption with Kd ranging between 6.3 to 11 µg/mLand Kf ranging from 5.2 to 7.4 µg/mL, signifying weak adsorption of MBC in selected soils. Desorption for soil sample 1 was highest because all parameters favor the quicker MBC molecules detachment from soil particles deficient in organic matter. Results for current investigation were examined for statistical significance via one way analysis of variance goodness of fit determined with residual plots in Minitab. In the remediation assay, Prunus dulcis shells were used as precursors for activated carbon preparation. MBC was removed up to 100 % in the lowest concentration, i.e. 2.5 ppm, while only 23 % of MBC was removed in case of 7.5 ppm, expressing the concentration dependency of the remediation assay. Prunus dulcis shells derived activated carbon is a sustainable and non-toxic material, which opens the future arenas for further research on its commercialization potential for remediation of soil compartment.Carbendazim (methyl-2-benzimidazole carbamate i.e. MBC) was investigated for pedospheric adsorption-desorption, mobility and effective removal via Prunus dulcis derived activated carbon in addition to physical and chemical characterization of selected soils. MBC was adsorbed into six agriculturally soils with distinctive characteristics via batch-equilibrium method and was evaluated via linear and Freundlich models. The highest value for linear and Freundlich adsorption coefficients i.e. Kd and Kf (8.8 µg/mL and 11 µg/mL respectively) corresponds to soil sample 6 having organic matter (3.3 %) and clay (18 %). Soils exhibited variable affinity towards MBC adsorption with Kd ranging between 6.3 to 11 µg/mLand Kf ranging from 5.2 to 7.4 µg/mL, signifying weak adsorption of MBC in selected soils. Desorption for soil sample 1 was highest because all parameters favor the quicker MBC molecules detachment from soil particles deficient in organic matter. Results for current investigation were examined for statistical significance via one way analysis of variance goodness of fit determined with residual plots in Minitab. In the remediation assay, Prunus dulcis shells were used as precursors for activated carbon preparation. MBC was removed up to 100 % in the lowest concentration, i.e. 2.5 ppm, while only 23 % of MBC was removed in case of 7.5 ppm, expressing the concentration dependency of the remediation assay. Prunus dulcis shells derived activated carbon is a sustainable and non-toxic material, which opens the future arenas for further research on its commercialization potential for remediation of soil compartment
PRODUCCIÓN DE BIOGÁS MEDIANTE CODIGESTIÓN DE ESTIÉRCOL BOVINO Y RESIDUOS DE COSECHA DE TOMATE (Solanum lycopersicum L.)
Get PDFAnaerobic digestion is an alternative to reduce pollution problems due to the open sky disposal of waste, such as manures and agricultural residues; besides, it is an option for the generation of alternative energies due to biogas production. The aim of this work was to evaluate the co-digestion of cattle waste with tomato crop residues. The experimental design was completely randomized under a 2 × 2 factorial arrangement, considering two levels of manure (20 and 50 %) and two pH initial levels (6.8 and 7.5). It was found that by adjusting the pH to 7.5 using 20 or 50 % manure, the total production of biogas and methane increased 100 %, compared to that obtained in digesters starting at pH 6.8. In digesters where 50 % of manure and 50 % of tomato crop residues were used, the methane content reached 45 %, which is the minimum to be used as combustible. The use of 20 % manure and 80% tomato crop residues produced 35 to 37 % methane. The 50:50 proportion manure:tomato residues best treatment was in with pH adjust at 7.5 . The resulting digestate did not present phytotoxicity in the test with lettuce seeds, and its coliform and salmonella was below those indicated in standard NOM 004-SEMARNAT.La digestión anaeróbica es una alternativa para reducir problemas de contaminación que puede ocasionar el almacenamiento de residuos a cielo abierto, como es el caso del estiércol y residuos de cosecha; además, es una opción para la generación de energía por la obtención de biogás combustible. El objetivo del trabajo fue evaluar la codigestión de estiércol bovino con residuos de cosecha de tomate. Se utilizó un diseño completamente al azar con arreglo factorial 2 × 2, con dos niveles de estiércol (20 y 50 %) y dos niveles de pH inicial (6.8 y 7.5). Se encontró que al ajustar el pH inicial a 7.5 usando 20 o 50 % de estiércol, se duplicó la producción total de biogás y de metano, respecto a la obtenida en los digestores que iniciaron a pH 6.8. En los digestores donde se utilizó 50 % de estiércol y 50 % de residuos de cosecha de tomate, se alcanzó un contenido de metano de 45 %, que es el mínimo para utilizarse como combustible; empleando 20 % de estiércol y 80 % de residuos de cosecha de tomate se produjo de 35 a 37 % de metano. La proporción 50:50 estiércol:residuos de cosecha de tomate, con ajuste de pH inicial a 7.5, fue el mejor sistema para producir biogás combustible. El total de los digestatos producidos no presentaron fitotoxicidad en la prueba de germinación con semillas de lechuga y los contenidos de coliformes y salmonella estuvieron por debajo de los indicados en la norma NOM 004-SEMARNAT
CHARACTERIZATION OF UNTREATED AND COMPOSTED BIOCHAR DERIVED FROM ORANGE AND PINEAPPLE PEELS
Get PDFBiochar production is a waste management option for agro-businesses and it is widely used to sequester carbon and to improve soil fertility. The preferred feedstock to produce biochar has been lignin and cellulose rich materials, or a mixture of industrial or animal residues. However, residues rich in soluble sugars, pectin and polysaccharides, such as fruit wastes, have been rarely used and are widely available. Furthermore, the release of toxic compounds has been reported when untreated biochars are used as soil amendments. Here we test if composting is able to eliminate toxicants and to improve biochar characteristics. We produced biochar out of orange and pineapple peels by pyrolysis, and characterized the physical and chemical properties of untreated and composted biochars. The analyses show that the untreated biochar has a high soluble salt and C content, an alkaline nature and high porosity. The composting process increased the pH, micronutrients, exchangeable cations, oxygen-based functional groups and the labile carbon, and reduced the PAHs and dioxins. Our results reveal that orange and pineapple peels are suitable raw materials for producing biochar but should be composted before using them as soil amendments.Biochar production is a waste management option for agro-businesses and it is widely used to sequester carbon and to improve soil fertility. The preferred feedstock to produce biochar has been lignin and cellulose rich materials, or a mixture of industrial or animal residues. However, residues rich in soluble sugars, pectin and polysaccharides, such as fruit wastes, have been rarely used and are widely available. Furthermore, the release of toxic compounds has been reported when untreated biochars are used as soil amendments. Here we test if composting is able to eliminate toxicants and to improve biochar characteristics. We produced biochar out of orange and pineapple peels by pyrolysis, and characterized the physical and chemical properties of untreated and composted biochars. The analyses show that the untreated biochar has a high soluble salt and C content, an alkaline nature and high porosity. The composting process increased the pH, micronutrients, exchangeable cations, oxygen-based functional groups and the labile carbon, and reduced the PAHs and dioxins. Our results reveal that orange and pineapple peels are suitable raw materials for producing biochar but should be composted before using them as soil amendments