Disposición a pagar por mejorar la calidad del aire en Irapuato, Guanajuato, México

Air quality in the municipality of Irapuato, Guanajuato, Mexico, is one of the primary concerns of the state, largely due to the growth in industry and population. The objective of this research was to determine the willingness-to-pay (WTP) of Irapuato residents for improving environmental quality. The contingent valuation method was employed, utilizing a logit model based on data collected from surveys conducted among the inhabitants. A sample of 100 was obtained with the simple random sampling method. The results indicate that 90% of the respondents have a perception of air pollution as being between bad and very bad, while 10% perceive the air quality as good or very good. The average WTP obtained was 32.50 MXN per month per family. At higher levels of education and income, as well as among respondents who have had any disease related to environmental pollution, the willingness to pay for an improvement in air quality increased by 5.8%, 8.7%, and 12.8%, respectively. The above suggests involving the residents in the search for possible solutions.La calidad del aire en el municipio de Irapuato, Guanajuato, México, es uno de los principales problems de la entidad debido al incremento de la industria y de la población. El objetivo de la presente investigación fue determinar la disponibilidad a pagar (DAP) de los habitantes de Irapuato para mejorar la calidad ambiental. Se utilizó el método de valoración contingente con un modelo logit basado en datos de encuestas aplicadas a los habitantes. Se obtuvo una muestra de 100 con el método de muestreo aleatorio simple. Los resultados indican que la percepción del 90 % de los encuestados sobre la contaminación del aire varía de mala a muy mala, mientras que el 10 % restante percibe que la calidad del aire es buena o muy buena. La DAP promedio obtenida fue de 32.50 MXN mensuales por familia. A niveles más altos de escolaridad e ingresos, y si el encuestado ha presentado alguna enfermedad relacionada con la contaminación ambiental, la disposición a pagar una mejora en la calidad del aire fue mayor en 5.8, 8.7 y 12.8 %, respectivamente. Lo anterior sugiere involucrar a los habitantes en la búsqueda de posibles soluciones

Evaluation of China’s provincial eco-efficiency with the explainable boosting machine (EBM) model and Tobit regression

The explainable boosting machine (EBM) model measures China’s provincial eco-efficiency, and the Tobit regression model reveals internal driving factors to provide consultation for promoting China’s green development based on the panel data of 30 provinces from 2000 to 2018. The findings of this article are as follows: provincial-level regional ecological efficiency is low, growth is slow, regional differentiation is significant, and development still has a trend of incoordination and multi-polarization. From the perspective of global autocorrelation, the Moran index is significantly positive, and the province eco-efficiency of the first grade presents a positive spatial correlation and has the characteristics of spatial agglomeration. The regression analysis results show that the economic level, the FDI, the level of technological innovation, and the level of human capital are the main influencing factors of eco-efficiency, and there are spatial differences. Relevant suggestions are based on the status and influencing factors of the unbalanced development heterogeneity of provincial eco-efficiency in China

Actividad enzimática ligninolítica de dos poblaciones de Ganoderma spp. en interacción con Trichoderma spp.

The objectives of the present study were to evaluate the ligninolytic enzymatic activity (LEA = laccase, manganese peroxidase [MnP] and lipase peroxidase [LiP]) of two Ganoderma spp. populations (ruderal and urban), determine the type of fungal interaction of each population in co-cultures with Trichoderma spp. strains, and quantify the LEA in the interactions. Seven ruderal and seven urban strains were isolated, their daily growth rate (DGR) and LEA were determined and compared. With three strains from each population with the best DGR, co-cultures with three Trichoderma spp. strains were established (T85, T98 and T99). Ruderal strains produce more MnP and LiP activities, but have lower DGR compared to urban strains. Laccase activity was the same in both populations. The most common interaction between Ganoderma spp. and Trichoderma spp. was the inhibition at contact. Ruderal strains of Ganoderma spp. (4R and 9R) when grown in monoculture did not show MnP activity; however, when they interact with Trichoderma spp., MnP was present (between 150 to 3000%) and increased LiP (between 13 to 51%) activities. In urban strains of Ganoderma spp. laccase (between 8 to 183%), MnP (between 24 to 144%) and LiP (between 5 to 6268%) activities increased in interactions with Trichoderma spp. The LEA in each population was variable, the most common interaction between Ganoderma spp. and Trichoderma spp. was block at contact with significant increases in LEA.Los objetivos del presente estudio fueron evaluar la actividad enzimática ligninolítica (AEL = lacasa, manganeso peroxidasa [MnP]) y lipasa peroxidasa [LiP]) de dos poblaciones de Ganoderma spp. (ruderal y urbana), determinar el tipo de interacción fúngica de cada población en cocultivos con cepas de Trichoderma spp. y cuantificar la AEL en las interacciones. Se aislaron siete cepas ruderales y siete urbanas, se determinó y comparó su tasa de crecimiento diario (TCD) y su AEL. Con tres cepas de cada población con mejor TCD, se establecieron cocultivos con tres cepas de Trichoderma spp. (T85, T98 y T99). Las cepas ruderales presentaron más actividad MnP y LiP, pero menor TCD en comparación con las cepas urbanas. La actividad de la lacasa fue igual en ambas poblaciones. La interacción más común entre Ganoderma spp. y Trichoderma spp. fue la inhibición al contacto. Las cepas ruderales de Ganoderma spp. (4R y 9R) cuando crecen en monocultivo no presentaron actividad MnP; sin embargo, cuando interactúan con Trichoderma, la MnP se presentó (entre 150 a 3000 %) e incrementó la LiP (entre 13 al 51 %). En cepas urbanas de Ganoderma spp. la actividad lacasa (entre 8 a 183 %), MnP (entre 24 a 144 %) y LiP (entre 5 a 6268 %) aumentó en las interacciones con Trichoderma. La AEL en cada población fue variable, la interacción más común entre Ganoderma spp. y Trichoderma spp. fue el bloqueo al contacto con incrementos significativos en la AEL

Coastline stability analysis of Zhoushan-Liuheng lng terminal project based on remote sensing

Seabed evolution research around Zhoushan Liuheng LNG receiving station project, which mainly includes collecting, analyzing and sorting data of environmental investigation, was conducted by the second Institute of Oceanography, MMR. Based on the data of remote sensing and field survey for different years, the comprehensive research methods of dynamic geomorphology, sedimentology, stratigraphy and mathematical simulation are used to carry out the geomorphological investigation of the sea area near the Zhoushan Liuheng LNG terminal project. This paper makes a detailed analysis of the beach dynamics, seabed scouring and silting change characteristics of the project sea area, and makes a prediction of the beach channel scouring and silting adjustment trend caused by sea related projects, which provides a scientific basis for optimizing the plane layout of Zhoushan Liuheng LNG receiving station project and insight for other researchers who focus on coastline change and remote sensing

Actividad de celulasas y lacasas de Pleurotus ostreatus por fermentación en medios sólidos con subproductos del maíz (Zea mays L.)

Maize by-products (corn stover, totomoxtle and stubble) could serve as a substrate to produce enzyme extracts by solid fermentation (SF). The objective of this study was to quantify the activity of cellulase and laccase enzymes of Pleurotus ostreatus strains at five and ten days of SF. The SF was carried out in Erlenmeyer flasks with 50 g of substrate (80% humidity) inoculated with 5 g of a strain and incubated at 30 ºC. At each fermentation time, the enzymatic extract was obtained and crude protein (CP), organic matter (OM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were determined from the solid ferment. The experimental design was a 2x3x2 factorial arrangement in a completely randomized design; using strains, substrates and fermentation time as factors. Cellulase enzyme activity and CP showed no differences between strains and substrate types (p > 0.05). The SF at ten days showed higher cellulase activity and CP than at five days; the highest laccase activity was in the SF for five days using strain P15 and corn stover or stubble; the ferment with stubble showed lower NDF than totomoxtle and corn stover; the solid ferment at ten days showed higher ADF than at five days of SF; the SF with ten days using stubble and strain MR showed lower OM (p < 0.05). In conclusion, olote and totomoxtle are effective substrates in SF to produce enzymatic extracts of cellulases and laccases, and the nutrient content of the substrate changed with fermentation time.Los subproductos del maíz (olote, totomoxtle y rastrojo) podrían servir como sustrato para producir extractos enzimáticos por fermentación sólida (FS). El objetivo de esta investigación fue cuantificar la actividad de enzimas celulasas y lacasas de cepas de Pleurotus ostreatus a cinco y diez días de FS. La FS se realizó en matraces Erlenmeyer con 50 g de sustrato (80 % humedad) inoculados con 5 g de una cepa e incubados a 30 ºC. En cada tiempo de fermentación se obtuvo el extracto enzimático y al fermento sólido se le determinó proteína cruda (PC), materia orgánica (MO), fibra detergente neutro (FDN) y fibra detergente ácido (FDA). El diseño experimental fue un arreglo factorial 2x3x2 en un diseño completamente al azar; usando cepas, sustratos y tiempo de fermentación como factores. La actividad enzimática de las celulasas y la PC no mostraron diferencias entre cepas y tipos de sustrato (p > 0.05). La FS a 10 d mostró mayor actividad de las celulasas y PC que a los cinco días; la mayor actividad de las lacasas fue en la FS por cinco días usando la cepa P15 y olote o rastrojo; el fermento con rastrojo presentó menor FDN que totomoxtle y olote; el fermento sólido a diez días mostró mayor FDA que a cinco días de FS; la FS con diez días usando rastrojo y la cepa MR mostró menor MO (p < 0.05). En conclusión, olote y totomoxtle son sustratos efectivos en FS para producir extractos enzimáticos de celulasas y lacasas, además el contenido de nutrientes del sustrato se modificó con el tiempo de fermentación

Resistencia a tetraciclinas en Escherichia coli aislada de aguas superficiales y residuales de Tamaulipas, México

Antibiotic resistance represents a threat to global health that increases morbidity and mortality in the population. The excessive and indiscriminate use of antibiotics has led to the emergence and spread of resistant bacteria. Tetracyclines have been one of the most widely used antibiotics because of their broad spectrum and low cost; they are frequently found in aquatic environments because of their low mobility and persistence in such sources. Therefore, the aim of this work was to evaluate tetracycline resistance in Escherichia coli strains isolated from surface water and wastewater in northeastern Tamaulipas, Mexico. In this study, 50 strains of E. coli were analyzed. Susceptibility testing showed that 54% of E. coli strains were resistant to tetracycline, of which 16 and 26% were resistant to minocycline and doxycycline, respectively. Resistance to streptomycin, ampicillin, and sulfamethoxazole-trimethoprim was also identified. Regarding the tet genes, tet(A) was the most prevalent at 74 %, while intI was found at 22 % (p > 0.05). In the conjugation assay, 41 % (11/25) of E. coli strains showed potential to transfer resistance to tetracycline, and only tet(A) was transferred to the recipients in 81 %, while intI was transferred in 27 %. Finally, E. coli strains isolated on the surface and wastewater of northeastern Tamaulipas represent a health and environmental risk because of the potential to spread their resistance in the aquatic environment and other environments and bacterial communities.La resistencia a los antibióticos representa una amenaza para la salud mundial que incrementa la morbilidad y mortalidad de la población. El uso excesivo e indiscriminado de antibióticos ha conducido a la aparición y propagación de bacterias resistentes. Las tetraciclinas han sido uno de los antibióticos más utilizados por su amplio espectro y bajo costo, y son frecuentemente detectados en ambientes acuáticos por su baja movilidad y persistencia. El objetivo de este trabajo fue evaluar la resistencia a tetraciclinas en aislados de Escherichia coli de aguas superficiales y aguas residuales en el noreste de Tamaulipas, México. Se analizaron 50 aislados de E. coli, de los cuales el 54 % fue resistente a tetraciclina; de este porcentaje, 16 y 26 % fueron resistentes a doxiciclina y minociclina, respectivamente. También se identificó resistencia a estreptomicina, ampicilina y trimetoprim-sulfametoxazol. De los genes tet, el más prevalente fue tet(A) en 74 %, mientras que intI se detectó en 22 % (p > 0.05). En el ensayo de conjugación plasmídica, 41 % de los aislados de E. coli transfirieron la resistencia a tetraciclina. Sólo tet(A) se transfirió a las receptoras en 81 %, en tanto que intI en 27 %. Cinco replicones plasmídicos fueron identificados en las transconjugantes. Los aislados de E. coli obtenidos de aguas superficiales y residuales del noreste de Tamaulipas representan un riesgo sanitario y ambiental, ya que tienen el potencial de trasferir los genes de resistencia, no sólo en el medio acuático sino también a otros ambientes y comunidades bacterianas

Anammox microbial activity in sodium saline soil of former Lake Texcoco, Mexico

The Anammox process, involving transformation of ammonium to dinitrogen, is well known in aquatic ecosystems. However, this anaerobic process in soil has been little explored, even less in extremophile soils. The saline-sodic soil of the former Lake Texcoco exposed to desertification with irrigation projects using wastewater of Mexico City, is a unique environment, yet little is known about its microbial ecology. The objective of this study was to examine the presence of Anammox microorganisms and their microcosm activity after a period of Anammox enrichment (229 days). Microcosm kinetics monitored after the 229 days enrichment experiment, showed a significant removal of ammonium and nitrite, with a significant production of dinitrogen. The stoichiometric conversion of NO2– and NH4+ to N2 gas is complete in the studied soils, based on an Anammox process where 1 mole of NH4+ resulted in 1.02 moles of N2. The presence of the Anammox functional gene hzoA was observed in saline-sodic soils of the former Lake Texcoco. The Anamx1 and Anamx2 operational taxonomic units (OTU) are phylogenetically close to a bacterium of the phylum Planctomycetes from a wastewater treatment reactor and marine environment (AB257585.1 and HE654780.1, respectively). Those two OTU represent indigenous or exogenous Anammox microorganisms phylotypes. The existence of microorganisms with Anammox activity in a saline-sodic alkaline soil is of great interest for the understanding of the nitrogen cycle in extremophile soils.The Anammox process, involving transformation of ammonium to dinitrogen, is well known in aquatic ecosystems. However, this anaerobic process in soil has been little explored, even less in extremophile soils. The saline-sodic soil of the former Lake Texcoco exposed to desertification with irrigation projects using wastewater of Mexico City, is a unique environment, yet little is known about its microbial ecology. The objective of this study was to examine the presence of Anammox microorganisms and their microcosm activity after a period of Anammox enrichment (229 days). Microcosm kinetics monitored after the 229 days enrichment experiment, showed a significant removal of ammonium and nitrite, with a significant production of dinitrogen. The stoichiometric conversion of NO2– and NH4+ to N2 gas is complete in the studied soils, based on an Anammox process where 1 mole of NH4+ resulted in 1.02 moles of N2. The presence of the Anammox functional gene hzoA was observed in saline-sodic soils of the former Lake Texcoco. The Anamx1 and Anamx2 operational taxonomic units (OTU) are phylogenetically close to a bacterium of the phylum Planctomycetes from a wastewater treatment reactor and marine environment (AB257585.1 and HE654780.1, respectively). Those two OTU represent indigenous or exogenous Anammox microorganisms phylotypes. The existence of microorganisms with Anammox activity in a saline-sodic alkaline soil is of great interest for the understanding of the nitrogen cycle in extremophile soils

Tratamiento electroquímico mejorado para la remoción de metales de suelos contaminados por pasivos ambientales mineros

Mining environmental liabilities (MEL) are metal-intensive wastes that have the potential to contaminate the surrounding soil, adversely affecting water and air quality, degrading ecosystems, and causing toxic effects on human health. This study used electrochemical treatment as a remediation technique to decontaminate soil affected by MEL. Through a mixed factorial design, the effects of the improvement solutions, acetic acid, and nitric acid, and three distances from the soil with respect to the anode, on the residual concentration and one-dimensional spatial distribution of Pb, Cd, and Zn were investigated. The tests were carried out in triplicate, in acrylic cells, for five days, submitted to 30 V of power, and with nitric acid as cathode fluid. The results showed that nitric acid reduces 4.0, 11.5, and 11.3 times the content of Pb, Cd, and Zn compared to acetic acid, that is, the highest removal percentages of Pb, Zn, and Cd were 40, 34, and 23 %, respectively, when using nitric acid. Moreover, the one-dimensional spatial distribution of metals in the post-treatment soil was not an increasing concentration gradient from the anode region to the cathodic region, but was rather a homogeneous trend. Therefore, using nitric acid as the enhancement fluid confirmed the viability of the electrochemical treatment, although it should be enhanced under other experimental conditions to achieve higher remediation rates.Los pasivos ambientales mineros (PAM) son residuos con alta carga de metales que tienen el potencial de contaminar el suelo circundante, afectar negativamente la calidad del agua y aire, degradar los ecosistemas y provocar efectos tóxicos en la salud humana. Este estudio utilizó el tratamiento electroquímico como técnica de remediación para descontaminar un suelo afectado por PAM. A través de un diseño factorial mixto se investigó los efectos de las soluciones de mejora, ácido acético y ácido nítrico, y tres distancias del suelo respecto al ánodo, sobre la concentración residual y distribución espacial unidimensional de Pb, Cd y Zn. Los ensayos se realizaron por triplicado, en celdas de acrílico, durante cinco días, sometidos a 30 V de potencia y con ácido nítrico como fluido catódico. Los resultados demostraron que el ácido nítrico reduce 4.0, 11.5 y 11.3 veces el contenido de Pb, Cd y Zn en comparación con el ácido acético, es decir, que los mayores porcentajes de remoción del Pb, Zn y Cd fueron 40, 34 y 23 % respectivamente, al emplear ácido nítrico. Asimismo, la distribución espacial unidimensional de los metales en el suelo después del tratamiento, no fue un gradiente de concentración creciente desde la región anódica hacia la región catódica, sino una tendencia homogénea. Por tanto, emplear ácido nítrico como fluido de mejora confirmó la viabilidad del tratamiento electroquímico, aunque se debería potenciar en otras condiciones experimentales para alcanzar mayores tasas de remediación

Evaluation method of the coordination degree between landscape protection and tourism development in the traditional village

Landscape protection and tourism development are a pair of contradictions in the revitalization of traditional villages. It is an important topic to study the coordination between them. This research reveals the interactive mechanism between the protection of traditional rural features and the development of tourism, based on which the evaluation model and index system of the coordination degree of the composite system are constructed. The result is illustrated by the example of the first three plots of traditional Chinese villages in the Gansu Longzhong area from 2013 to 2018. The evolution trend of the traditional village landscape protection subsystem, the development of the tourism subsystem, and the composite system’s coordination degree were analyzed. The results show that the coordination of traditional village landscape protection and tourism development composite system at the same base period gradually increases. Nevertheless, the coordination between adjacent base periods is at a low level. The increase in the synergy between the landscape protection subsystem and the tourism development subsystem tends to be the same, and the two subsystems are in a positive development that promotes each other. Based on the above conclusions, this research puts forward the coordination strategies and suggestions for the protection of traditional villages and tourism development

Bioindicadores de calidad del agua en la cuenca baja del río Ocoña, departamento de Arequipa, Perú, utilizando diatomeas epilíticas y su relación con algunos parámetros ambientales

The species richness and community structure of an epilithic diatom community and their relationship with physical, chemical and microbiological parameters in the lower reaches of the Ocoña river basin, Arequipa Department, Perú, were determined at three sampling points in January, May, and October 2019. Fifty-two taxa of the Bacillariophyta division were identified. Of the total taxa, 12 had a relative abundance greater than 2% and were used for canonical correspondence analysis. The highest species richness (39) occurred in October. The H’ diversity values (2.04 to 2.45 bit/cel) for January and October represent a community with normal diversity; while the values registered in May (0.51 to 1.58 bit/cel) are associated with low diversity. According to the Simpson Index, the highest dominance (0.18) occurred in May and was represented by Nitzschia inconspicua; equity (J) showed a uniform distribution in the diatom community in January (63%) and October (69%). From the canonical correspondence analysis, the taxa Diatoma moniliformis, Melosira varians, and Nitzschia palea presented a positive relationship with the environmental parameters pH, hardness, SO4–2, P, K, Na, and Mg, while Cocconeis placentula exhibited a positive correlation with pH, hardness, Ca, Mg, and Na. Likewise, Epithemia sorex, Nitzschia sp.1, and Ulnaria ulna showed a positive relationship with the highest Fe concentrations, while N. inconspicua was positively related to thermotolerant coliforms.Se determinó la riqueza y estructura de la comunidad de diatomeas epilíticas y su relación con parámetros físicos, químicos y microbiológicos en la cuenca baja del río Ocoña, Departamento de Arequipa, Perú, en tres puntos de muestreo, en los meses de enero, mayo y octubre de 2019. Se identificaron 52 taxa de la división Bacillariophyta. Del total de taxones, 12 presentaron una abundancia relativa superior al 2 % y se utilizaron para el análisis de correspondencia canónica. La mayor riqueza de especies (39) se presentó en el mes de octubre. Los valores de diversidad H’ (2.04 a 2.45 bit/cel) para enero y octubre representaron a una comunidad con una diversidad normal; mientras que los valores registrados en mayo (0.51 a 1.58 bit/cel) se asociaron a una diversidad baja. Según el Índice de Simpson la mayor dominancia (0.18) se presentó en el mes de mayo y estuvo representada por Nitzschia inconspicua, la equidad (J) mostró una distribución uniforme en la comunidad de diatomeas en los meses de enero (63 %) y octubre (69 %). Del análisis de correspondencia canónica, los taxones Diatoma moniliformis, Melosira varians y Nitzschia palea presentaron una relación positiva con los parámetros ambientales pH, dureza, SO4–2, P, K, Na y Mg; mientras que Cocconeis placentula presentó una correlación positiva con pH, dureza, Ca, Mg y Na. Asimismo, Epithemia sorex, Nitzschia sp.1 y Ulnaria ulna presentaron una relación positiva con las concentraciones más altas de Fe, mientras que N. inconspicua se relacionó positivamente con los coliformes termotolerantes