Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title><jats:p>As the reliance on transboundary groundwater is increasing globally, it is important to understand and address the specific issues raised by the assessment and management of transboundary aquifers (TBAs). Building on 20 years of TBA experience and through a three-pillar framework (assessment, cooperation-collaboration, shared management), the key elements to addressing TBA issues are described, including a multidisciplinary approach, identification of hotspot zones, local vs border-wide approaches, appropriate funding models, and an increased recognition of the role and value of each TBA.</jats:p>

<jats:title>Abstract</jats:title><jats:p>The volcanic Barva and Colima multiaquifer system is crucial for the drinking water supply of about 1.7 million people, about 30% of the population in Costa Rica. The complexity of this system and the simultaneous occurrence of anthropogenic and natural processes complicate the understanding of hydrochemical and hydrogeological dynamics, both essential for groundwater protection. This research aimed to develop a model for the discrimination of groundwaters according to the main withdrawn aquifer and flow path, assess interaquifer connections, and evaluate the main hydrochemical processes governing water quality. Samples (571) from 38 sampling sites, collected quarterly from 2016 to 2020, were analyzed for nitrate, major ions, and silica. Principal component analysis and discriminant analysis exhibited and validated sample grouping according to the primary aquifer system captured, i.e., Upper Barva, Lower Barva, Upper Colima, and Lower Colima, and the occurrence of two flow paths within the Lower Barva and Upper Colima aquifers. Hydrochemical and statistical analyses showed resilience to seasonal chemical variation in deeper aquifers and also three groundwater mixing processes. Lower Barva groundwater enriches in bicarbonate, magnesium, calcium, sodium, and silica, mainly due to weathering of mafic andesitic-basaltic lavas. The Upper and Lower Colima showed higher silica and major ion content, except for calcium, indicating longer residence times, dissolution from felsic andesitic minerals, and calcium adsorption by normal ion exchange. Weathering of aluminosilicates is the primary process governing groundwater quality in the four studied aquifers, whereas cation exchange, interaquifer leakage, and anthropogenic processes might modify the groundwater chemistry.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Karst aquifers are important resources for drinking water supply and are very vulnerable to contamination. Microbial concentrations at karst springs, in particular, often vary quickly over a short period of time. In this study, the response of microbial water quality and particle-size distribution of two alpine karst springs to rainfall events was investigated to test and validate parameters that can be used as early-warning systems for fecal contamination. At both investigated karst springs, total organic carbon, particle-size distribution (especially small particle fractions), and particle load show a good correlation to the fecal indicator bacteria <jats:italic>E. coli</jats:italic> and can therefore be used as a real-time indicator of fecal contamination at the investigated springs. In addition to conventional bacterial determination methods, the β-D-glucuronidase activity, which can be measured in near real-time, was used as a novel indicator parameter for fecal contamination. At the event scale, the β-D-glucuronidase (GLUC) activity shows a good correlation to <jats:italic>E. coli</jats:italic> and can be used as an additional real-time indicator of fecal contamination. For the studied springs, when they show two peaks in turbidity and small particles, these two parameters are suitable for an early warning system because the bacterial contamination occurs during the secondary peak of these parameters. These results highlight the vulnerability of karst aquifers and demonstrate the applicability of advanced measurement techniques in detecting fecal contamination in real-time, which is especially important given the time-consuming nature of conventional bacterial detection methods.</jats:p>

<jats:title>Abstract</jats:title><jats:p>The sources, mobility, and controlling processes of arsenic (As) in an aquifer system in the Cerritos-Guadalcazar area of Central Mexico were investigated. High As concentrations (up to 128 μg/L) in groundwater were found to be associated with both primary sources (rocks and tailings) and secondary sources (soil and sediments). The high As concentrations in the otherwise pristine Cerritos shallow granular aquifer are the result of a distant source of As-rich sediments eroded from a mineralized area in the recharge zone of a karstic aquifer. An intermediate groundwater flow system delivers the As load from the karstic to the granular aquifer. In addition, identification of a Na–Cl water type in the shallow granular aquifer indicates a regional flow; however, additional information is needed to corroborate this assumption. Local flows in the karstic aquifer are Ca–HCO<jats:sub>3</jats:sub> water type with low (&lt;1 μg/L) dissolved As concentrations. Principle axis factor analysis shows distinct groupings associated with different aquifer characteristics. The sulfate factor dominates in the southern area of the granular aquifer, which explains 30% of the total variance. The arsenic-uranium factor is expressed in samples from deep and dug wells tapping the basin sediments. A conceptual model was developed where the path of the As is shown. Three groups of samples showed negative correlation among deuterium excess and As concentrations. Evaporation modeling to simulate the As enrichment showed that evaporation processes play an important role in As behavior. This research can provide a tool for further studies in the Sierra Madre Oriental.</jats:p>