Revista Internacional de Contaminación Ambiental
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LOS ESPACIOS VERDES COMO ESTRATEGIA DE MITIGACIÓN DE LA CONTAMINACIÓN SONORA. EVALUACIÓN Y ANÁLISIS DEL PARQUE O’HIGGINS DE LA CIUDAD DE MENDOZA-ARGENTINA
Get PDFNoise pollution is one of the factors that deteriorate the environmental quality of cities, their habitability and productivity of their inhabitants. One of the viable strategies to mitigate this type of pollution are urban parks. These can be considered as acoustic vegetable screens that additionally provide numerous other benefits. The aim of this study is to quantify the sound levels and analyze the O’Higgins park characteristics in Mendoza city–Argentina, to determine its efficiency as a barrier to attenuate noise and improve the environmental quality. The sound levels are measured in four periods of the day and different points of the park (9) in summer and winter, with these, acoustic indicators have been calculated. The existing vegetation is characterized in situ with dasometric measurements. The first results show differences in sound pressure levels between seasons due to the presence of deciduous species that lose their foliage in winter (64-84 %). It is noted that for an effective masking of noise, the design, composition and distribution of park vegetation should be adjusted in terms of increasing the proportion of evergreen species that provide greater vegetation volume and lower transmissibility to noise.La contaminación sonora constituye uno de los factores que deterioran la calidad ambiental de las ciudades, su habitabilidad y la productividad de sus habitantes. Una de las estrategias viables para mitigar este tipo de contaminación son los parques urbanos. Éstos pueden considerarse como pantallas vegetales antirruido que aportan adicionalmente otros beneficios ambientales. El objetivo del trabajo es cuantificar los niveles de presión sonora y analizar las características del parque O’Higgins en la ciudad de Mendoza, Argentina, para determinar su eficiencia como barrera para atenuar el ruido y mejorar la calidad del entorno. Se miden los niveles de presión sonora en cuatro períodos del día y diferentes puntos del parque (9) mediante registros estacionales de verano e invierno, y a partir de los cuales se han calculado distintos indicadores acústicos. La vegetación existente se caracteriza mediante relevamientos in situ y mediciones dasométricas. Los primeros resultados muestran diferencias en los niveles de presión sonora entre estaciones a causa de la presencia de especies caducifolias que en invierno pierden el follaje (64-84 %). Se observa que para un enmascaramiento efectivo del ruido, el diseño, composición y distribución de la vegetación del parque debieran ajustarse en términos de aumentar la proporción de especies perennifolias que aporten mayor volumen de vegetación y menor transmisibilidad al ruido
FRECUENCIA DE HUEVOS DE Toxocara canis EN PARQUES PÚBLICOS DE MEXICALI, BAJA CALIFORNIA, MÉXICO
Get PDFA study was carried out in 56 public parks of the city of Mexicali, Baja California, Mexico to know the level of soil contamination by Toxocara canis eggs. The selection of parks was random and the duration of the sampling to estimate the variability of pollution with respect to the seasons was one year. The soil samples were analyzed using the flotation technique with saturated saline solution. It was found that the frequency of contaminated parks was 54 %, and specific contamination per parasite was found to be more frequent by Toxocara canis with 46.4 %, which was 16.1 % lower compared to a study carried out in 2007. Likewise, other parasite´s eggs like Ancylostoma caninum (5.3 %) were found, and one park was parasitized with Spirocerca spp. and Strongylus spp. (1.78 %). The contamination rate for T. canis eggs was 1.6 eggs per 66 g of soil, i.e., a low level of contamination compared to other studies in the country and in the world, even though it still represents a risk for public health.Se realizó un estudio en 56 parques públicos de la ciudad de Mexicali, Baja California, México, con la finalidad de conocer el nivel de contaminación del suelo con huevos de Toxocara canis. La selección de parques fue aleatoria y la duración del muestreo para estimar la variabilidad de la contaminación respecto a las estaciones fue de un año. Las muestras de suelo fueron analizadas con la técnica de flotación con solución salina saturada. Se encontró que la frecuencia de parques contaminados fue de 54 % y que la contaminación especifica más frecuente por parásito se debió a Toxocara canis con 46.4 %, nivel menor en 16.1 % comparado con un estudio realizado en 2007. Asimismo, se encontraron otros parásitos como Ancylostoma caninum (5.3 %) y finalmente, en un solo parque, Spirocerca spp. y Strongylus spp. (1.78 %). La concentración de contaminación por huevos de T. canis fue de 1.6 huevos por 66 g de suelo, valor bajo en comparación con otros estudios en el país y el mundo; aún así, representa un riesgo para la salud pública local
NECESSITY OF INTERVENTION POLICIES FOR TAILINGS IDENTIFIED IN THE ANTOFAGASTA REGION, CHILE
Get PDFThe aim of this work was to establish the intervention requirements of 30 tailings deposits located in the region of Antofagasta, Chile, identified in the National Tailings Survey carried out by the National Service of Geology and Mining of the Chilean government in 2017. For the evaluation, the data of 49 geochemical characterizations of the samples registered as of October 2017 were considered. The methodology used for evaluation was based on the Dutch Soil Regulation Circular, from which two ways of assessment were developed. The first approach uses a simple graphic method that depends only on the concentration of the elements in the solid phase of tailings and the percentage of clay in the soil. The second approach considers that the information related to the clay percentage is not available, therefore, this work defines the concepts of threshold factor and adjusted threshold factor. Using the proposed method, this work presents the analysis carried out on the elements of environmental significance related to mining activity in Chile: Cu, Cr, Ni, Zn, Pb, As, Cd and Hg. The methodology allows delimiting areas of foreseeable risks for people and/or environment, resulting in three criteria for each element: 1) requires intervention, 2) requires conditional intervention, 3) does not require intervention. These results are summarized by means of a final score that determines the level of priority assigned to each sample. The analysis of results indicates that Hg intervention is not required, there being only one case requiring conditional intervention. Regarding Cu and Zn, 100 % of the measurements indicated at least the requirement of a conditional intervention. Within the region, the commune of Sierra Gorda contains 67 % of the tailings whose intervention must be prioritized according to the score obtained (greater than four out of a possible maximum of eight). On the other hand, the two tailings of greater tonnage (the sites of Talabre and Laguna Seca) do not present a requirement for priority intervention at the moment.The aim of this work was to establish the intervention requirements of 30 tailings deposits located in the region of Antofagasta, Chile, identified in the National Tailings Survey carried out by the National Service of Geology and Mining of the Chilean government in 2017. For the evaluation, the data of 49 geochemical characterizations of the samples registered as of October 2017 were considered. The methodology used for evaluation was based on the Dutch Soil Regulation Circular, from which two ways of assessment were developed. The first approach uses a simple graphic method that depends only on the concentration of the elements in the solid phase of tailings and the percentage of clay in the soil. The second approach considers that the information related to the clay percentage is not available, therefore, this work defines the concepts of threshold factor and adjusted threshold factor. Using the proposed method, this work presents the analysis carried out on the elements of environmental significance related to mining activity in Chile: Cu, Cr, Ni, Zn, Pb, As, Cd and Hg. The methodology allows delimiting areas of foreseeable risks for people and/or environment, resulting in three criteria for each element: 1) requires intervention, 2) requires conditional intervention, 3) does not require intervention. These results are summarized by means of a final score that determines the level of priority assigned to each sample. The analysis of results indicates that Hg intervention is not required, there being only one case requiring conditional intervention. Regarding Cu and Zn, 100 % of the measurements indicated at least the requirement of a conditional intervention. Within the region, the commune of Sierra Gorda contains 67 % of the tailings whose intervention must be prioritized according to the score obtained (greater than four out of a possible maximum of eight). On the other hand, the two tailings of greater tonnage (the sites of Talabre and Laguna Seca) do not present a requirement for priority intervention at the moment
CARACTERIZACIÓN DE BACTERIAS RIZOSFÉRICAS DE SUELO CIRCUNDANTE A UNA PLANTA RECICLADORA DE PLOMO (Pb)
Get PDFThe aim of this research was to isolate and characterize rhizosphere bacteria of huizache (Acacia farneciana) and mesquite (Prosopis glandulosa), predominant vegetation surrounding a lead (Pb) recycling company. Bacteria were evaluated on their tolerance to Pb(NO3)2,andtheircapacity to produce indole-acetic acid (IAA) and siderophores using Salkowski and chrome azurol S (CAS) agar medium techniques, respectively. The bacterial isolates were identified through the 16S rRNA gene. Ten bacterial strains tolerated concentrations between 0.6 and 1.8 mM of Pb (NO3)2, of which seven strains had IAA production of up to 60 μg/mL and five strains showed siderophore production. Qualitatively, the bacterial strains L2, L48 and L67 presented a more intense orange halo than the bacterial strains L138 and L23, which indicates a positive reaction of siderophores production. Additionally, the siderophores production of the hydroxamate type produced by the bacterial strains L2, L48, L67, L138 and L23 was variable, between 0.02 and 0.054 μg/mL. The results of this research allow concluding that there are bacterial strains around the lead (Pb) recycling company with a high potential for phytoremediation processes.El objetivo del presente trabajo fue aislar y caracterizar bacterias rizosféricas de huizache (Acacia farneciana) y mezquite (Prosopis glandulosa), vegetación predominante en torno a una empresa recicladora de plomo (Pb). Se evaluaron la tolerancia de las bacterias a Pb(NO3)2 y su capacidad de producción de ácido indol-3-acético (AIA) y de sideróforos por medio de las técnicas de Salkowski y el medio cromo azurol S (CAS)-agar, respectivamente. Los aislados bacterianos se identificaron a través del gen 16S ARNr. Diez cepas bacterianas toleraron concentraciones de 0.6 a 1.8 mM de Pb(NO3)2, de las cualessiete cepas presentaron producción de AIA de hasta 60.0 μg/mL y cinco cepas presentaron producción de sideróforos. Cualitativamente, las cepas L2, L48 y L67 presentaron un halo de color naranja más intenso que las cepas L138 y L23, indicador de reacción positiva de producción de sideróforos. La producción de sideróforos del tipo hidroxamato por las cepas L2, L48, L67, L138 y L23 varió de 0.02 a 0.054 µg/mL. Los resultados permiten concluir que existen cepas bacterianas en torno a la empresa recicladora de Pb con un alto potencial para utilizarse en procesos de fitorremediación
IDENTIFICACIÓN DE LAS ZONAS CONTAMINADAS CON METALES PESADOS EN EL POLVO URBANO DE LA CIUDAD DE MÉXICO
Get PDFSeven million people die per year of cancer related to environmental pollution. Urban dust (UD) contains particles smaller than 10 μm that affect human health. In Mexico City (CDMX) only one study on UD has been conducted. The objective of this study was to identify the areas most likely to be contaminated by heavy metals (HM) contained in the UD of CDMX. Eighty nine UD samples were collected; the analysis of the HM concentration was made by X-ray fluorescence, and spatial analysis by interpolation with kriging indicator. The percentage of the area with the highest probability that HMs exceeded the maximum permitted limits (MPL) were: Cr (MPL 280 mg/kg), 0.55 %, southwest of the CDMX; Cr (MPL 64 mg/kg), 89 %, all CDMX and most of the conurbated areas (CA); Cu, 17 %, 11 municipalities and the northern CA; Ni, 13 %, center and southwest of the CDMX; Pb (MPL 140 mg/kg), 17.5 %, centric municipalities and the northwest CA; Pb (MPL 400 mg/kg), 2.2 %, centric municipalities and the northwest CA; V, 26 %, centric and southern municipalities and the northeast CA; Zn, 21 %, centric municipalities and the northern CA. Elements with a greater number of sites and contaminated surface are: Cr, Zn, Cu and Pb. The largest HM overlapping sites are those with Cu and Zn associations (15 %), and Cu and Pb associations (13 %). The municipalities Cuauhtémoc, Venustiano Carranza and Gustavo A. Madero are the most contaminated with heavy metals.Siete millones de personas mueren al año por cáncer relacionado con la contaminación ambiental. El polvo urbano (PU) contiene partículas < 10 µm que afectan la salud humana. En la Ciudad de México (CDMX) existe sólo un estudio de PU. El objetivo de este estudio fue identificar las zonas de la CDMX con mayor probabilidad de contaminación por metales pesados (MP) en el PU. Se recolectaron 89 muestras de PU y se midió la concentración de MP por fluorescencia de rayos X. El análisis espacial se realizó mediante interpolación con kriging indicador. El porcentaje de la superficie con mayor probabilidad de que los MP superen los límites máximos permitidos (LMP) fueron: Cr (LMP 280 mg/kg), 0.55 %, suroeste; Cr (LMP 64 mg/kg), 89 %, toda la CDMX y la mayoría de las áreas conurbadas (AC); Cu, 17 %, 11 delegaciones y AC del norte; Ni, 13 %, centro y suroeste; Pb (LMP 140 mg/kg), 17.5 %, delegaciones céntricas y AC del noroeste; Pb (LMP 400 mg/kg), 2.2 %, delegaciones céntricas y AC del noroeste; V, 26 %, delegaciones céntricas y del sur, así como AC del noreste; Zn, 21 %, delegaciones céntricas y AC del norte. Los elementos con mayor número de sitios y superficie contaminada son: Cr, Zn, Cu y Pb. Los sitios con mayor superficie de sobreposición de MP son aquellos con asociaciones entre Cu y Zn (15 %), y Cu y Pb (13 %). Las delegaciones Cuauhtémoc, Venustiano Carranza y Gustavo A. Madero son las más contaminadas con metales pesados
TOXICIDAD AGUDA DEL MALATION 500® Y TYSON 4E® EN Capitella sp.
Get PDFThe toxicity of Malation 500® and Tyson 4E®, whose active ingredients are malathion and chlorpyrifos ethyl, respectively, was experimentally determined using as test organism Capitella sp. collected in the Chetumal Bay and acclimated on lab. To do that, 48 h static toxicity bioassays were done using five nominal concentrations distributed in a logarithmic scale, a blank and three replicates for each bioassay chamber. Ten organisms were exposed to each concentration in crystallizer dishes with a sediment layer, saline solution and their respective volume of pesticide. Mortality was registered and median lethal concentrations (LC50) were determined through the Probit analysis with 95 % confident intervals. The LC50 were 27.79 ± 2.67 mg/L for Malation 500® and 7.46 ± 1.59 mg/L for Tyson 4E®, therefore this last one is more toxic. ANDEVA showed significant differences in the tested concentrations (p < 0.05). Malation 500® was classified as slightly toxic and Tyson 4E® as moderately toxic for Capitella sp. Both risk quotients of the pesticides (RQ < 1) indicate that the ecological risk is negligible.Se determinó la toxicidad aguda de los plaguicidas Malation 500® y Tyson 4E®, los cuales tienen como ingrediente activo al malatión y al clorpirifós etil respectivamente, empleando como organismo de prueba a Capitella sp. recolectado en la Bahía de Chetumal y aclimatado en condiciones de laboratorio. Para ello se realizaron bioensayos de toxicidad de tipo estático por 48 h utilizando cinco concentraciones nominales distribuidas con una escala logarítmica, tres réplicas por concentración y un control por cada cámara de bioensayos; se emplearon 10 organismos por réplica en cristalizadores con sedimento tratado, solución salina y su respectivo volumen del plaguicida. Se registró la mortalidad y se determinó la concentración letal media (CL50) mediante el análisis Probit con un intervalo de confianza de 95 %. Los valores de CL50 obtenidos fueron de 27.79 ± 2.67 mg/L para el malatión y 7.46 ± 1.59 mg/L para el clorpirifós etil; por lo tanto, se comprueba que este último fue el más tóxico. El análisis estadístico ANDEVA demostró que existen diferencias significativas entre las distintas concentraciones (p < 0.05). Malation 500® se clasificó como ligeramente tóxico y Tyson 4E® como moderadamente tóxico para Capitella sp. Los cocientes de riesgo de ambos plaguicidas (CR < 1) indican que su riesgo ecológico es despreciable
ARSENIC CONTENT, GRAIN SIZES AND CHEMICAL CHARACTERISTICS IN SURFACE SEDIMENTS OF THE URÍAS LAGOON, NW MEXICO
Get PDFAiming to detect possible impacts of human activities on the characteristics of the sediments of the Urías lagoon, which is a lagoonal system surrounded by the urban area of Mazatlán (NW Mexico), we determined the mean percentages of the main particle fractions, pH, CO32–, organic carbon and total arsenic content in the surficial sediments of six different zones of the Urías lagoon. Sand was the dominant size fraction throughout the whole system. The highest organic matter and the lowest pH values were found in adjacent sites to industrial activities, especially to fish processing. Most arsenic concentrations were within the values of the natural local background (12.6-27.3 mg/kg), with the possible exception of sediments close to the industrial area, especially those nearby the fish processing plants, where the mean As (45.2 ± 9.3 mg/kg) exceeded the level which may have adverse effects on marine organisms (41.6 mg/kg). However, it is not excluded that such levels are results rather from the combined effect of the hydrodynamic and sediments dynamic of sediment associated to local enrichments background of the region.Aiming to detect possible impacts of human activities on the characteristics of the sediments of the Urías lagoon, which is a lagoonal system surrounded by the urban area of Mazatlán (NW Mexico), we determined the mean percentages of the main particle fractions, pH, CO32–, organic carbon and total arsenic content in the surficial sediments of six different zones of the Urías lagoon. Sand was the dominant size fraction throughout the whole system. The highest organic matter and the lowest pH values were found in adjacent sites to industrial activities, especially to fish processing. Most arsenic concentrations were within the values of the natural local background (12.6-27.3 mg/kg), with the possible exception of sediments close to the industrial area, especially those nearby the fish processing plants, where the mean As (45.2 ± 9.3 mg/kg) exceeded the level which may have adverse effects on marine organisms (41.6 mg/kg). However, it is not excluded that such levels are results rather from the combined effect of the hydrodynamic and sediments dynamic of sediment associated to local enrichments background of the region
WATER POVERTY INDEX IN ARID ZONES: THE BARRIL AQUIFER, SANTO DOMINGO, SAN LUIS POTOSÍ, MEXICO
Get PDFIn Mexico, 73.7 % of the territory is made up of arid and semi-arid zones where groundwater is the main source of supply for the population’s various activities. The municipality of Santo Domingo is in such a case, with a predominantly dry climate and a 99 % dependence on groundwater of the Barril aquifer. Climatic, geological, and hydrological factors have conditioned not only access to water in quantity and quality, but also the type of vegetation and productive activities. Calculating a water poverty index (WPI) allows the evaluation of water poverty taking into account both physical and socioeconomic factors related to the availability of water. The WPI results from the weighted sum of six components: resources, access, use, capacity, quality, and environment, on an evaluation scale of 0 to 100. The objective of this work was to estimate the WPI in a region with extreme climatic conditions, scarce vegetation, contamination problems in soils and water such as those in Santo Domingo, obtaining a score of 27 points.In Mexico, 73.7 % of the territory is made up of arid and semi-arid zones where groundwater is the main source of supply for the population’s various activities. The municipality of Santo Domingo is in such a case, with a predominantly dry climate and a 99 % dependence on groundwater of the Barril aquifer. Climatic, geological, and hydrological factors have conditioned not only access to water in quantity and quality, but also the type of vegetation and productive activities. Calculating a water poverty index (WPI) allows the evaluation of water poverty taking into account both physical and socioeconomic factors related to the availability of water. The WPI results from the weighted sum of six components: resources, access, use, capacity, quality, and environment, on an evaluation scale of 0 to 100. The objective of this work was to estimate the WPI in a region with extreme climatic conditions, scarce vegetation, contamination problems in soils and water such as those in Santo Domingo, obtaining a score of 27 points
PRÁCTICAS DE MANEJO Y ANÁLISIS DE RIESGO POR EL USO DE PLAGUICIDAS EN LA COMARCA LAGUNERA, MÉXICO.
Get PDFFrom 2005 to 2015, 9653 ha/year of vegetables were cultivated in the Comarca Lagunera, where the intensive use of pesticides stands out. The objective of this study was to characterize the practices of pesticide use and management in horticultural crops in this region and the risk they entail to health and the environment. The study was carried out during 2015 in the Comarca Lagunera of Coahuila and Durango, Mexico. A stratified random sampling system was used with a 95 % confidence interval, a bias of ± 5 % and a sample size of 90 surveys applied to vegetable producers. The vegetables with the largest area planted were, in descending order, melon, watermelon, pepper and tomato. Organophosphorus pesticides were the most used, applied by 65.7 % of the population surveyed, The active ingredient with the largest application was carbofuran with 42 %. Only 40 % of producers have received training on the proper use and management of agrochemicals and 75 % of producers do not have personal protection equipment. Sixty one percent of the producers leave the containers in the field or burn them after use and 34 % have suffered pesticide poisoning at least once. Training is sporadic and the advanced average age of the producers increases the environmental risk and health by the use of these agrochemicals.En el periodo 2005-2015 se cultivaron en promedio 9653 ha/año de hortalizas en la Comarca Lagunera, donde destaca el uso intensivo de plaguicidas. El objetivo de este estudio fue caracterizar las prácticas de uso y manejo de plaguicidas en cultivos hortícolas de esa región y el riesgo que suponen para la salud y el ambiente. El estudio se llevó a cabo durante 2015 en la Comarca Lagunera de Coahuila y Durango, México. Se usó un sistema de muestreo estratificado al azar con un nivel de confianza del 95 %, una precisión de ± 5 % y un tamaño de muestra de 90 encuestas aplicadas a productores de hortalizas. Las hortalizas con mayor superficie sembrada fueron, en orden descendente, melón, sandía, chile y jitomate. Los plaguicidas organofosforados fueron los de mayor uso; fueron aplicados por el 65.7 % de la población encuestada. El ingrediente activo de mayor aplicación fue carbofurano, con el 42 %. Sólo el 40 % de los productores han recibido capacitación sobre el uso y manejo adecuado de agroquímicos y el 75 % de los productores no cuenta con equipo de protección personal. El 61 % de los productores dejan los envases en el campo o los queman después de usarlos y el 34 % han sufrido intoxicación por plaguicidas al menos una vez. La capacitación es esporádica y la edad avanzada promedio de los productores incrementa el riesgo ambiental y a la salud por el uso de estos agroquímicos