Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Water pollution with arsenic has received special attention due to its health implications for the population. Therefore, its removal from groundwater is of vital importance. The main objective of this work was to investigate the removal performance of dissolved arsenic in multi-ionic solutions using a low-cost mineral material and, in parallel, to be able to compare its sorption capacity from its nature as a chemically modified form. To do this, fixed bed columns packed with natural zeolites (ZN) and chemically modified (ZMQ) with 1 M H2SO4 were implemented. Sorption studies showed that chemical conditioning improved the maximum sorption capacity (qe), the breakthrough time, the exhaustion time and the effluent volume with a concentration equal to or less than 10 μg/L, correspondingly by 150, 45, 88 and 281 %, concerning the ZN. The breakthrough curves for the removal of As (V) were fitted with various mathematical models, being the Thomas nonlinear model the one that best reproduced the kinetics of sorption under the implemented operating conditions. The X-ray diffraction concluded that there is no structural change in the zeolite after the chemical modification, therefore, the increase in the sorption capacity of the ZMQ was attributed to the morphological and elemental chemical composition changes on their surface. These results show that the ZMQ can be used as a viable alternative, from the point of view of purifying efficiency, concerning its non-acidified form, for the removal of As (V).

This work evaluates the social construction of risk associated with urban flooding in the southern area of the city of San Luis Potosí, Mexico. Firstly, we examine the 1970s and 1980s urban policies that originated the current problem of annual flooding and that led to the social production of a risky urban space; also, we analyze the rainfall regime in the study area and the political speech that identifies precipitation as the main cause of urban flooding. Secondly, we analyze the social organization of the community and the local strategies to cope with floods. The neighbors use these strategies to prevent and reduce the damages caused by floods, but they are considered technically deficient by the city authorities. The results of this research show the social construction of risky urban space in the context of land privatization, the industrialization of the city, and the social and economic inequality that led to the recurrent flooding in the study neighborhood (El Aguaje). Furthermore, the results show the local strategies used by the residents to protect their properties and safeguard their health. Such strategies include streets, housing modifications, and social organizations to demand action from the local government.

In this research work, a simulation exercise is carried out for the guarantees in the water demands in Mexicali, considering a control scenario with period from 2005 to 2018 and a future scenario with projection from 2020 to 2040. In said projections the reductions in water deliveries to Mexico stipulated in Minute 323 of the IBWC are included. The AQUATOOL water resources management software has been used, with which the guarantees in the water supply to the control scenario and in the future have been evaluated, also including a new industrial demand with an amount of up to 20 Hm3 per year. This new demand was evaluated both in the future scenario and in the control period, to simulate what could have happened if it had existed previously. The result shows that there are occasions in the control scenario in which there are some failures in the supply guarantees. The current situation of stress and pressure on water resources, added to the effects of climate change, in the Colorado River basin and especially in the city of Mexicali, make it unwise to add new demands to the system, since this intensifies competition by water resources.

El artículo examina la tributación del uso de los recursos hídricos rusos para varios tipos de uso del agua. El uso de los recursos hídricos puede regularse en diferentes jurisdicciones de distintas maneras. Si bien los objetivos de las diferentes autoridades pueden ser los mismos (p. ej., fomentar el uso más eficiente de los recursos hídricos), los medios para alcanzarlos pueden variar. El uso de la nueva forma de pago obligatorio (en forma de impuesto al agua) prácticamente no modificó la metodología para justificar el tamaño de las tarifas en comparación con el pago obligatorio anterior: pago por pago por el uso de cuerpos de agua. El impuesto al agua ocupa una parte insignificante de los ingresos del presupuesto consolidado ruso. La tasa reducida del impuesto al agua cuando se toma agua para abastecer a la población conlleva una disminución significativa (entre un 77 y 82 %, según el año) de la carga fiscal para este tipo de uso del agua. Cuando se toma agua en exceso del límite establecido para un usuario de agua específico se aplica una tasa aumentada (cinco veces). El peso específico del impuesto sobre el agua, cobrado en 2006-2019 a una tasa mayor, varió en el rango de 2 a 10 %.

The basins in the plain present particularities from the approach of the hydrological processes that take place there. They are characterized by presenting a predominance of vertical water movements (evapotranspiration-infiltration) over horizontal movements (runoff), showing a strong interrelation between surface and underground water. The La Picasa Lagoon basin is defined as a naturally depressed humid pampa region with an undulating plain relief that has low sectors of temporary flooding and permanent lagoons without a defined drainage network. It is an inter-jurisdictional endorheic basin between the provinces of Córdoba, Santa Fe, and Buenos Aires (Argentina) that has suffered recurrent floods between 2014 and 2017 caused by an increase in the average level of the lagoon reaching historical maximums, producing floods, and affecting infrastructure, transport, and agricultural activity. Due to these problems, through the application of hydrological and hydraulic models, the behavior of La Picasa basin system is quantified and evaluated to avoid future floods. In the present work, a hydrological model is applied using the HEC-HMS free tool and a 1D/2D hydraulic model using the HEC-RAS free tool, where the system of channels and reservoirs that make up the system is considered. The flood marks in reservoirs and La Picasa Lagoon are analyzed, and it is defined as regulating the variation of levels in the different reservoirs within permitted ranges. These models are a useful tool for studying future hydrological situations that may occur around the study area.

En este estudio se utilizó un nuevo tipo de floculante microbiano combinado con coagulante de cloruro férrico de polialuminio (PAFC) en el experimento de coagulación-floculación de agua de limo de carbón. Se investigaron los efectos de la dosis de PAFC, la dosis de biofloculante y el pH sobre la turbidez y la demanda química de oxígeno (COD) del agua de limo de carbón. Los resultados mostraron que las mejores condiciones para eliminar la turbidez del agua de limo y la COD mediante la prueba de factor único fueron las siguientes: la dosis de PAFC fue de 37.5 mg/l, la dosis de biofloculante fue de 0.75 mg/l y el pH fue de 7.0. A través de la prueba ortogonal se identificó que los factores más influyentes para la turbidez y eliminación de COD son el pH y la dosis de PAFC, respectivamente. La mejor condición de la coagulación-floculación fue con una dosis de PAFC de 50.0 mg/l, una dosis de biofloculante de 0.5 mg/l y el pH de 7.0. Bajo esta condición, se obtuvo una eficiencia de remoción de turbidez del 93.2 % y una eficiencia de remoción de COD del 47.2 %.

Much research worldwide focuses on finding processes and materials with enough capacity to decontaminate water efficiently and cheaply. With dry and crushed cellulose from the E. crassipes plant, experiments are carrying out on a laboratory scale with interesting results due to its plenty and efficiency in the retention of pollutants, but the implementation in the industry of these processes with this biomass for the treatment of its effluents It has been a bit wasteful. The objective of this research is to design bio-columns with dry and crushed biomass of E. crassipes for the treatment of water contaminated with Cr (VI), where it was transforming with iron chloride to favor the cation exchange capacity. The adsorption process was experimenting on a batch laboratory scale to determine the adsorption capacities through the Langmuir isotherms. With these capacities, the experimental set-up of the biofilter was designing on a pilot scale and subsequently, a material balance was carrying out to determine the volume necessary for the efficient removal of Chromium (VI). A biocolumn system with E. crassipes material was building for the effective treatment of 85 % of chromium (VI) and a biocolumn with E. crassipes with iron for treatment of around 95 % of chromium present in the water. Concluding that this treatment system has high reliability to remove water contaminated with chromium (VI).

San Luis is an Argentine province whose semi-arid climate led to the construction of artificial water bodies throughout its territory, generating concern about the environmental and hydrological effects, on a local and regional scale, that these reservoirs could cause. In this sense, evapotranspiration (ET), the main water loss in any ecosystem, represents an important part of the water balance. Likewise, bird communities respond to the presence of new water mirrors, where the humidity represents one of the most relevant variables determining the vegetation composition and food availability. For this reason, ET was related to bird richness and abundance in this study, using ET as a surrogate of humidity. Thus, based on remotely sensed ET data, the time-space dynamics of the ET were determined before and after the construction of the reservoirs, obtaining space thresholds of their impact. In addition, the bird’s composition, and abundance were related to water mirrors here and correlated with the ET and vegetation dynamics. Results indicate an increase in the ET means values up to 500 m from the reservoir’s banks. New water mirrors, higher ET values, and heterogeneous habitats with moderate disturbance correlate to high bird diversity. Reservoirs used for touristic purposes are related to new urbanizations and generalist birds.

River’s sinuosity is a characteristic pattern of rivers around the world that can be interpreted as a sign of the hydro-sedimentological instability of these systems. Such instability leads to the formation of meanders whose distribution is far from being an aleatory process reproducing a self-organized dynamic that can be described using fractals, settling a connection poorly explored up to date. The present study aims to contribute to this topic by measuring for the first time the meandering fractal dimension ( ) of seven Chilean rivers distributed from north to south of Chile. This dimension takes values close to unity in agreement with the morphological patterns observed in the rivers, suggesting that this parameter can be a helpful indicator to characterize the geometry of complex hydrographic systems.

The precise determination of groundwater recharge variation is a fundamental task for the sustainable planning of groundwater resources, particularly in heavily pressured aquifers. In order to determine the spatial and temporal variability of groundwater recharge in an urban aquifer with a humid climate, such as the San Salvador aquifer, two Mass Balance methods were used (one in the subsurface zone, Soil Water Balance (SWB) and another in the saturated zone, Chloride Mass Balance (CMB)). The SWB was calculated on a daily scale for four years (2012-2015) through the modified Thornthwaite and Mather method, using a set of daily climatic data grids and physical data from the study area. The CMB was used to determine the groundwater recharge in drilled wells and springs samples taken during 2009 and 2016, in the upper part of the basin, where various studies suggest that the main aquifer recharge occurs. The results of the SWB indicate a strong temporal and spatial variation of the recharge in the study area, which can vary between 326 and 561 mm year-1, in dry and wet years, respectively. The CMB results showed consistency with the SWB, groundwater recharge values ranged between 313 and 693 mm year-1. In both methods the mean annual recharge is similar and represents between 20% and 30% of the precipitation. The application of both methods could be used in similar areas, the selection of the method will depend on the objectives of the study.