Groundwater is the main source of drinking water supply in most urban environments around the world. The content of potentially toxic elements is increasing in many groundwater systems owing to inadequate groundwater recharge, aquifer overexploitation, natural source release, or various anthropogenic activities that lead to groundwater quality degradation. The ingestion of groundwater contaminated with potentially toxic elements has been reported to have harmful health effects. This study aimed to assess the presence of several potentially toxic elements (Al, As, B, Cr, Cu, Fe, Mn, and Zn) in groundwater of the Monterrey metropolitan area in Northern Mexico and the carcinogenic and noncarcinogenic human health risks associated with exposure. Multivariate statistics and geospatial analysis were applied to identify the causative determinants that modify the groundwater quality along the metropolitan area. Mean concentrations of trace metals remained below drinking water standards and World Health Organization guidelines. The risk of harmful effects on human health due to ingestion of all eight metal(loid)s in groundwater was assessed as 2.52 × 10−2 for adults and 2.16 × 10−2 for children, which can be considered as negligible chronic risk and a very low cancer risk. However, the risks of oral consumption of Cr being carcinogenic to children and adults were 7.9 × 10−3 and 9.2 × 10−4, respectively. As these values exceeded the target risk of 1 × 10−4, it can thus be considered “unacceptable”.
This work focuses on the effects of vegetation on a fluid flow pattern. In this numerical research, we verify the applicability of a simpler turbulence model than the commonly used k-" model to predict the mean flow through vegetation. The novel characteristic of this turbulence model is that the horizontal mixing-length is explicitly calculated and coupled with a multi-layer approach for the vertical mixing-length, within a general three-dimensional eddy-viscosity formulation. This mixing-length turbulence model has been validated in previous works for different kinds of non-vegetated flows. The hydrodynamic numerical model used for simulations is based on the Reynolds-averaged Navier–Stokes equations for shallow water flows, where a vegetation shear stress term is considered to reproduce the effects of drag forces on flow. A second-order approximation is used for spatial discretization and a semi-implicit Lagrangian–Eulerian scheme is used for time discretization. In order to validate the numerical results, we compare them against experimental data reported in the literature. The comparisons are carried out for two cases of study: submerged vegetation and submerged and emergent vegetation, both within an open channel flow.
This work focuses on the study of thermal dispersion of plumes emitted by power plants into the sea. Wastewater discharge from power stations causes impacts that require investigation or monitoring. A study to characterize the physical effects of thermal plumes into the sea is carried out here by numerical modeling and field measurements. The case study is the thermal discharges of the Presidente Adolfo López Mateos Power Plant, located in Veracruz, on the coast of the Gulf of Mexico. This plant is managed by the Federal Electricity Commission of Mexico. The physical effects of such plumes are related to the increase of seawater temperature caused by the hot water discharge of the plant. We focus on the implementation, calibration, and validation of the Delft3D-FLOW model, which solves the shallow-water equations. The numerical simulations consider a critical scenario where meteorological and oceanographic parameters are taken into account to reproduce the proper physical conditions of the environment. The results show a local physical effect of the thermal plumes within the study zone, given the predominant strong winds conditions of the scenario under study.
Sustainability indices are a way of quantifying the progress that a certain region has achieved in terms of sustainability that can be transmitted to society and decision makers. The watershed approach has become relevant for managing water resources and ensuring their sustainability. This study combined the above two approaches by applying an adapted watershed sustainability index (WSI) to evaluate the sustainable development of the Santiago–Guadalajara River basin (SGRB), which passes through Guadalajara, the second-most populous city in Mexico. The river is the most polluted waterway in the country. The WSI of each sub-basin places the SGRB at a sustainability level between low in the upper and lower basin region and intermediate in the central basin region. Regions with a low sustainability level are characterized by environmental degradation due to changes in land use, while in the region with intermediate sustainability, the factor that most affect the evaluation is water availability. An overall sustainability score of WSI = 0.36 was obtained for the study area, which is lower than that of any other basins evaluated in the same manner around the world. These results send a clear message to decision makers of the three government levels, in charge of the environmental sustainability of the basin, of the need to take action to facilitate its recovery.