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Papers by Arturo Antonio

Water, Nov 28, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Pontificia Universidad Católica del Perú eBooks, Mar 21, 2019

TesisEl autor se plantea a través de una investigación dogmática, el problema de cómo surge la pr... more TesisEl autor se plantea a través de una investigación dogmática, el problema de cómo surge la preocupación por la evaluación de la conducta de los hombres públicos, analizando el juicio político y la acusación constitucional, desde el origen de la Institución llamada impeachment en la Inglaterra medieval, su extinción para ceder su lugar a la responsabilidad política del ministro consejero o gabinete, su paso a los Estados Unidos de Norteamérica y aplicación en un sistema de gobierno diferente, vale decir, de un modelo monárquico parlamentario a uno presidencial; frente al modelo kelseniano o europeo que encarga esta atribución al órgano titular de la jurisdicción constitucional orgánica; para desembocar en Iberoamérica y su coexistencia con el Juicio de Residencia Colonial, con el propósito de analizar estas instituciones en el Perú a partir de su tratamiento en las diferentes Constituciones que hemos tenido, las leyes de Responsabilidad de Funcionarios Públicos, de 06 de junio de 1834 y 25 de septiembre de 1868 así como los Reglamentos de las Cámaras Legislativas, analizando las posibilidades interpretativas e insuficiencias de los artículos 99º y 100º de la Constitución Política, naturaleza jurídica y algunos casos sustanciados, para finalmente ocuparse del Proceso Judicial a que da lugar la acusación constitucional y los pronunciamientos que sobre el particular ha hecho nuestro Tribunal Constitucional, lo que evidencia muchas veces prejuicios en la sustanciación de los casos, en detrimento de las notas características del debido proceso legal de los procesados, lo cual frente a la evidencia histórica peruana resulta penosamente cierto y es un indicador de la inutilidad política de una institución que cuando el Perú sale a la vida independiente en 1821, en el país cuna del juicio político Inglaterra, era ya un fósil jurídico, pues el último caso data de 1806, contra el Primer Vizconde de Melville

EGU General Assembly Conference Abstracts, Apr 1, 2017

Ricardo Sánchez-Murillo (1), Germain Esquivel-Hernández (1), Leonardo Corrales-Salazar (1), Laura... more Ricardo Sánchez-Murillo (1), Germain Esquivel-Hernández (1), Leonardo Corrales-Salazar (1), Laura Castro-Chacón (2), Ana María Durán-Quesada (3), Manuel Guerrero-Hernández (4), Valeria Delgado (5), Javier Barberena (5), Katia Montenegro-Rayo (5), Heyddy Calderón (6), Carlos Chevez (7), Tania Peña-Paz (8), Saúl García-Santos (8), Pedro Ortiz-Roque (9), Yaneth Alvarado-Callejas (10), Laura Benegas (10), Arturo Hernández-Antonio (11), Marcela Matamoros-Ortega (12), Lucía Ortega (13), and Stefan Terzer-Wassmuth (13)

Bulletin of Environmental Contamination and Toxicology, 2019

Artisanal and small-scale gold mining (ASGM) has been performed in the southern Ecuadorian Amazon... more Artisanal and small-scale gold mining (ASGM) has been performed in the southern Ecuadorian Amazon since the colonial period. However, its effects on fluvial systems have been poorly investigated. Thus, in order to calculate the normalized enrichment factors (NEF) of several heavy metals in fluvial sediments of the Zamora River basin (Ecuadorian Amazon), we analyzed bottom sediments along ASGM-affected and unaffected river sections. The results indicated that sediments of the Congüime River have NEF between 2.2 and 2.3 for Cu (moderate contamination) and higher than 3 for Mn, Zn, Pb, and Hg (severe contamination). Similarly, a severe contamination is also observed in the lower Nangaritza River, due to sediments of this sector have NEF > 3 for Zn, Pb, and Hg. Bottom sediments from the Nambija and Zamora rivers showed a severe contamination with Hg (NEF > 3), suggesting the existence of ASGM activities in the upper Zamora River basin.

Micromachines, Jan 22, 2018

In recent years, ever-increasing scientific knowledge and modern high-tech advancements in micro-... more In recent years, ever-increasing scientific knowledge and modern high-tech advancements in micro- and nano-scales fabrication technologies have impacted significantly on various scientific fields. A micro-level approach so-called "microfluidic technology" has rapidly evolved as a powerful tool for numerous applications with special reference to bioengineering and biomedical engineering research. Therefore, a transformative effect has been felt, for instance, in biological sample handling, analyte sensing cell-based assay, tissue engineering, molecular diagnostics, and drug screening, etc. Besides such huge multi-functional potentialities, microfluidic technology also offers the opportunity to mimic different organs to address the complexity of animal-based testing models effectively. The combination of fluid physics along with three-dimensional (3-D) cell compartmentalization has sustained popularity as organ-on-a-chip. In this context, simple humanoid model systems which ...

Chemosphere, Jan 3, 2018

The Mezquital Valley system is the world's oldest and largest example with regard to use of u... more The Mezquital Valley system is the world's oldest and largest example with regard to use of untreated wastewater for agricultural irrigation. Because of the artificial high recharge associated with the Mezquital Valley aquifers, groundwater is extracted for human consumption, and there are plans to use this groundwater as a water resource for Mexico City. Thus, this study analyzed 218 organic micro-contaminants in wastewater, springs, and groundwater from Mezquital Valley. Five volatile organic compounds (VOCs) and nine semi-volatile organic compounds (SVOCs) were detected in the wastewater used for irrigation. Only two SVOCs [bis-2-(ethylhexyl) phthalate and dibutyl phthalate] were detected in all the wastewater canals and groundwater sources, whereas no VOCs were detected in groundwater and springs. Of the 118 pharmaceutically active compounds (PhACs) and 7 reproductive hormones measured, 65 PhACs and 3 hormones were detected in the wastewater. Of these, metformin, caffeine, a...

Water, 2017

Environmental isotope tracers have been a useful tool in providing new insights into hydrologic p... more Environmental isotope tracers have been a useful tool in providing new insights into hydrologic processes. In Mexico, there have been several studies reporting different values for δ 18 O and δ 2 H for certain geographical areas. The objective of this study is to achieve the isotopic characterization of rainfall and groundwater and to report the comprehensive understanding of groundwater flow processes around and within the Calera aquifer and, consequently, its potential recharge sites. The samples used for the stable isotope analysis (δ 18 O, δ 2 H) were measured using a GV-Isoprime isotope-ratio mass spectrometer at the Isotopy Laboratory of the Water Center for Latin America and the Caribbean. The δD of precipitation ranged between −110.20‰ and 10.11‰, with a mean of −55.67‰ ± 27.81‰. The δ 18 O ranged between −17.80‰ and 2.74‰, with a mean of −9.44‰ ± 4.74‰. The δD of groundwater ranged between −81.92‰ and −36.45‰, with a mean of −66.05‰ ± 8.58‰. The δ 18 O ranged between −18.26‰ and −8.84‰, with a mean of −12.35‰ ± 2.12‰. The local meteoric water line of the Zacatecas state is δD = −2.03 + 5.68 δ 18 O. The groundwater samples were clustered into four groups. The clustering of the samples led to the finding that streamflows play a significant role in the hydrological balance as a source of local recharge to the aquifer.

Environmental monitoring and assessment, 2017

The Monterrey metropolitan area (MMA) is the third greatest urban area and the second largest eco... more The Monterrey metropolitan area (MMA) is the third greatest urban area and the second largest economic city of Mexico. More than four million people living in this megacity use groundwater for drinking, industrial and household purposes. Thus, major ion and trace element content were assessed in order to investigate the main hydrochemical properties of groundwater and determine if groundwater of the area poses a threat to the MMA population. Hierarchical cluster analysis using all the groundwater chemical data showed five groups of water. The first two groups were classified as recharge waters (Ca-HCO3) coming from the foothills of mountain belts. The third group was also of Ca-HCO3 water type flowing through lutites and limestones. Transition zone waters of group four (Ca-HCO3-SO4) flow through the valley of Monterrey, whereas discharge waters of group 5 (Ca-SO4) were found toward the north and northeast of the MMA. Principal component analysis performed in groundwater data indicat...

Hydrological Processes, 2017

The quality of the groundwater supplying drinking water to the Guadalajara metropolitan area has ... more The quality of the groundwater supplying drinking water to the Guadalajara metropolitan area has deteriorated due to both endogenic and exogenic processes. Previous studies of this complex neotectonic volcanic environment suggest that the sources of contamination here are underground fluids derived from an active volcanic center and surface wastewater derived from regional land-use intensification. This study uses isotopic, gaseous, and chemical signatures to more comprehensively characterize this groundwater flow and its contamination paths. Groundwater is mainly recharged at the La Primavera Caldera to the west and is discharged into the Santiago River to the east. The exception to this trend is the Toluquilla area, where groundwater most likely represents rainfall originating from outside the basin limits. Evaporation affects groundwater in these areas, especially waters that have been affected by recycling below urban areas in the Atejamac area and by intensive agricultural activity in the Toluquilla area. Additionally, we present evidence that groundwater flow through alluvial sediments and tuffs in deeper wells mixes with a lower aquifer unit in basaltic-andesitic rocks, which are in contact with hydrothermal fluids. Groundwater ages range from postbomb in the western and northwestern regions of the study area (i.e., the Atemajac aquifer unit) to Late Pleistocene in the southern and southeastern regions (i.e., the Toluquilla aquifer unit). Recently recharged water records little mixing and is located mostly in or near the La Primavera volcanic system. As groundwater undergoes gravitational flow towards discharge areas, it mixes with older water components. Chloride and sodium concentrations above natural background levels are primarily related to volcanic activity, nitrate is associated with human activities, and sulfate originates from both anthropogenic sources and water-rock interactions. Nitrate originating from land-use activities (such as sewers, septic tanks, landfills, and agricultural fields) that is introduced into the deeper part of the groundwater system is expected to travel with the groundwater to the discharge areas because oxidizing conditions will prevent microbial reduction. See Supplementary Information.

Procedia Earth and Planetary Science, 2017

Chemical and isotopic data were used to explain the geochemistry and the hydrothermal influence i... more Chemical and isotopic data were used to explain the geochemistry and the hydrothermal influence in a groundwater system in Guadalajara, México. According to the measured parameters and the characteristics of the groundwater, four water groups were identified: i) thermal waters with high temperatures and high concentrations of Cl, Na, HCO 3 and the presence of Li, Mn, F and Mg, apparently of old age with a long residence time; ii) mixed waters of Na-HCO 3 to HCO 3 water type, which represent a mixture of cold water and thermal water; iii) polluted water characterized by high concentrations of nitrate and sulfate derived from urban and agricultural return flow; iv) cold water characterized by low temperature values, low concentration of Cl, Na and salinity, of Na-HCO 3 type. This last group represents modern water located in the recharge zone. Finally, major proportions of hydrothermal fluids are largest in the well waters of the first group varying from 1.9 to 12.5 %. The other groups show hydrothermal fractions below 1.7%. Groundwater with elevated hydrothermal proportions is located to the southeastern area of the Toluquilla aquifers. This study identifies some processes that govern the groundwater and hydrothermal mixing.

Procedia Earth and Planetary Science, 2017

The Monterrey Metropolitan Area (MMA) is the third greatest urban area of Mexico. Owing to the ra... more The Monterrey Metropolitan Area (MMA) is the third greatest urban area of Mexico. Owing to the rapid industrialization and urbanization of this city, more water resources are necessary in this semi-arid region. Thus, the objectives of this work were to characterize the chemical properties of groundwater supplied to MMA and to assess inter-annual variations in the water chemistry. Three groups of water were identified: recharge waters from mountain belts dominated by marine sedimentary rocks (Ca-HCO 3 type), transition zone waters from alluvial sediments (Ca-HCO 3-SO 4 type) and waters flowing through conglomerates and alluvial sediments of the northeastern MMA (Ca-SO 4 type). The ionic composition and the salinity gradient of each water group were in agreement with the topographic flow paths of the study area. The non-parametric Mann-Whitney U-test indicated that there have been no significant changes on the groundwater quality supplied to the MMA between the years 2006 and 2012.

Procedia Earth and Planetary Science, 2017

Coastal areas are attractive places for the establishment of urban settlements owing to the many ... more Coastal areas are attractive places for the establishment of urban settlements owing to the many benefits in terms of quality of life. An example of these areas is La Paz in Southern Baja California, Mexico, where demographic growth and agricultural activities under dry climatic conditions are threatening the availability of water resources. In recent years, an increasing salinity of groundwater has been identified, however, the origin of the salinity is not clear. Near the coastline, salt water intrusion is considered to be the main factor, while others play a role for increased salinities in the middle and upper aquifer zone. The study, using a hydrochemical tool analysis shows that the salinity of the coastline is the result of over-exploitation of wells, which increases saline intrusion resulting in a reverse cation exchange. It also indicates that the salinization of water in the recharge area is product of carbon dioxide dissolution and weathering of rock-forming silicate minerals, and in the central part result from cycling and use of fertilizer in agriculture.

Environmental Earth Sciences, 2016

Groundwater from the La Paz arid coastal aquifer in Baja California, Mexico, is essentially the o... more Groundwater from the La Paz arid coastal aquifer in Baja California, Mexico, is essentially the only source of drinking water for the local population and tourists, as well as irrigation water for agricultural needs. The intensive exploitation of the aquifer and water cycling has resulted in groundwater abatement (up to 10 m) and high salinity (up to *5800 mg l-1). A study using hydrochemistry, isotopic (deuterium, oxygen-18 and carbon-14) and gaseous tracers (chlorofluorocarbons CFC-11, CFC-12, CFC-113), as well as multivariate statistics, was developed to elucidate groundwater composition, flow and occurrence. Groundwater is of meteoric origin, and a large proportion is subject to evaporation. The primary natural recharge is generated in the El Novillo and Las Cruces ranges, and groundwater subsequently flows in a SE-NW direction toward the coast. The initial water type is the result of discordant dissolution of silicate minerals and ion exchange on soils. In the lower plain portion, the aquifer system is recharged from irrigation return flow and seawater intrusion, which significantly affects groundwater chemistry. Nitrate and chloride concentrations indicate that groundwater is highly affected by an overuse of fertilizers in agricultural activities, but there is little effect from urban activities. Seawater intrusion has progressed rapidly during the past decade, and the impact currently extends 13 km inland. Radiocarbon residence time calculations suggest that groundwater is modern, with the exception of Chametla and El Centerario sites in the central and western lowlands with ages of up to *5000 years. These waters indicate an additional recharge source for the upconing of fossil groundwater or regional flow.

Revista Internacional De Contaminacion Ambiental, Apr 1, 2011

Palabras clave: cuenca hidrológica, COP, atrazina y desetilatrazina, DDD y DDE RESUMEN En este es... more Palabras clave: cuenca hidrológica, COP, atrazina y desetilatrazina, DDD y DDE RESUMEN En este estudio se presenta el inventario de plaguicidas y una evaluación de la contaminación de agua y sedimentos en dos zonas agrícolas de México. Se analizaron plaguicidas triazínicos, fenoxiclorados y organoclorados, incluyendo seis contaminantes orgánicos persistentes (COP). Aunque el uso de atrazina ha sido prohibido y restringido en varias partes del mundo, en México este herbicida se sigue usando sin restricción alguna, los resultados obtenidos demuestran que afecta a la calidad del agua en una de las zonas agrícolas. Las concentraciones de atrazina y de su metabolito (desetilatrazina) en muestras de agua, rebasaron el límite para agua de consumo humano de 2 µg L-1 propuesto por la Organización Mundial para la Salud (WHO 2008) y el de la Comunidad Europea que establece un límite de 0.1 µg L-1 (European Parliament 1998). Los metabolitos del plaguicida DDT (DDD y DDE), excedieron el límite basal para calidad de sedimentos (ISQG por sus siglas en inglés) del criterio del Consejo de Ministros del Ambiente de Canadá para sedimentos en cuerpos de agua dulce, aunque no rebasan el límite de probable efecto (PEL por sus siglas en inglés) (CCME 2003). Aunque se restringió el uso de DDT en la agricultura en México (DOF 1991), los resultados muestran que los metabolitos de este plaguicida se continúan encontrando en muestras ambientales debido a su larga vida media. Se plantea la necesidad de vigilar mediante monitoreos en los cuerpos de agua, los plaguicidas encontrados en este estudio en concentraciones que exceden los criterios y límites establecidos.

Hydrology and Earth System Sciences Discussions, 2015

Water, Nov 28, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Pontificia Universidad Católica del Perú eBooks, Mar 21, 2019

TesisEl autor se plantea a través de una investigación dogmática, el problema de cómo surge la pr... more TesisEl autor se plantea a través de una investigación dogmática, el problema de cómo surge la preocupación por la evaluación de la conducta de los hombres públicos, analizando el juicio político y la acusación constitucional, desde el origen de la Institución llamada impeachment en la Inglaterra medieval, su extinción para ceder su lugar a la responsabilidad política del ministro consejero o gabinete, su paso a los Estados Unidos de Norteamérica y aplicación en un sistema de gobierno diferente, vale decir, de un modelo monárquico parlamentario a uno presidencial; frente al modelo kelseniano o europeo que encarga esta atribución al órgano titular de la jurisdicción constitucional orgánica; para desembocar en Iberoamérica y su coexistencia con el Juicio de Residencia Colonial, con el propósito de analizar estas instituciones en el Perú a partir de su tratamiento en las diferentes Constituciones que hemos tenido, las leyes de Responsabilidad de Funcionarios Públicos, de 06 de junio de 1834 y 25 de septiembre de 1868 así como los Reglamentos de las Cámaras Legislativas, analizando las posibilidades interpretativas e insuficiencias de los artículos 99º y 100º de la Constitución Política, naturaleza jurídica y algunos casos sustanciados, para finalmente ocuparse del Proceso Judicial a que da lugar la acusación constitucional y los pronunciamientos que sobre el particular ha hecho nuestro Tribunal Constitucional, lo que evidencia muchas veces prejuicios en la sustanciación de los casos, en detrimento de las notas características del debido proceso legal de los procesados, lo cual frente a la evidencia histórica peruana resulta penosamente cierto y es un indicador de la inutilidad política de una institución que cuando el Perú sale a la vida independiente en 1821, en el país cuna del juicio político Inglaterra, era ya un fósil jurídico, pues el último caso data de 1806, contra el Primer Vizconde de Melville

EGU General Assembly Conference Abstracts, Apr 1, 2017

Ricardo Sánchez-Murillo (1), Germain Esquivel-Hernández (1), Leonardo Corrales-Salazar (1), Laura... more Ricardo Sánchez-Murillo (1), Germain Esquivel-Hernández (1), Leonardo Corrales-Salazar (1), Laura Castro-Chacón (2), Ana María Durán-Quesada (3), Manuel Guerrero-Hernández (4), Valeria Delgado (5), Javier Barberena (5), Katia Montenegro-Rayo (5), Heyddy Calderón (6), Carlos Chevez (7), Tania Peña-Paz (8), Saúl García-Santos (8), Pedro Ortiz-Roque (9), Yaneth Alvarado-Callejas (10), Laura Benegas (10), Arturo Hernández-Antonio (11), Marcela Matamoros-Ortega (12), Lucía Ortega (13), and Stefan Terzer-Wassmuth (13)

Bulletin of Environmental Contamination and Toxicology, 2019

Artisanal and small-scale gold mining (ASGM) has been performed in the southern Ecuadorian Amazon... more Artisanal and small-scale gold mining (ASGM) has been performed in the southern Ecuadorian Amazon since the colonial period. However, its effects on fluvial systems have been poorly investigated. Thus, in order to calculate the normalized enrichment factors (NEF) of several heavy metals in fluvial sediments of the Zamora River basin (Ecuadorian Amazon), we analyzed bottom sediments along ASGM-affected and unaffected river sections. The results indicated that sediments of the Congüime River have NEF between 2.2 and 2.3 for Cu (moderate contamination) and higher than 3 for Mn, Zn, Pb, and Hg (severe contamination). Similarly, a severe contamination is also observed in the lower Nangaritza River, due to sediments of this sector have NEF > 3 for Zn, Pb, and Hg. Bottom sediments from the Nambija and Zamora rivers showed a severe contamination with Hg (NEF > 3), suggesting the existence of ASGM activities in the upper Zamora River basin.

Micromachines, Jan 22, 2018

In recent years, ever-increasing scientific knowledge and modern high-tech advancements in micro-... more In recent years, ever-increasing scientific knowledge and modern high-tech advancements in micro- and nano-scales fabrication technologies have impacted significantly on various scientific fields. A micro-level approach so-called "microfluidic technology" has rapidly evolved as a powerful tool for numerous applications with special reference to bioengineering and biomedical engineering research. Therefore, a transformative effect has been felt, for instance, in biological sample handling, analyte sensing cell-based assay, tissue engineering, molecular diagnostics, and drug screening, etc. Besides such huge multi-functional potentialities, microfluidic technology also offers the opportunity to mimic different organs to address the complexity of animal-based testing models effectively. The combination of fluid physics along with three-dimensional (3-D) cell compartmentalization has sustained popularity as organ-on-a-chip. In this context, simple humanoid model systems which ...

Chemosphere, Jan 3, 2018

The Mezquital Valley system is the world's oldest and largest example with regard to use of u... more The Mezquital Valley system is the world's oldest and largest example with regard to use of untreated wastewater for agricultural irrigation. Because of the artificial high recharge associated with the Mezquital Valley aquifers, groundwater is extracted for human consumption, and there are plans to use this groundwater as a water resource for Mexico City. Thus, this study analyzed 218 organic micro-contaminants in wastewater, springs, and groundwater from Mezquital Valley. Five volatile organic compounds (VOCs) and nine semi-volatile organic compounds (SVOCs) were detected in the wastewater used for irrigation. Only two SVOCs [bis-2-(ethylhexyl) phthalate and dibutyl phthalate] were detected in all the wastewater canals and groundwater sources, whereas no VOCs were detected in groundwater and springs. Of the 118 pharmaceutically active compounds (PhACs) and 7 reproductive hormones measured, 65 PhACs and 3 hormones were detected in the wastewater. Of these, metformin, caffeine, a...

Water, 2017

Environmental isotope tracers have been a useful tool in providing new insights into hydrologic p... more Environmental isotope tracers have been a useful tool in providing new insights into hydrologic processes. In Mexico, there have been several studies reporting different values for δ 18 O and δ 2 H for certain geographical areas. The objective of this study is to achieve the isotopic characterization of rainfall and groundwater and to report the comprehensive understanding of groundwater flow processes around and within the Calera aquifer and, consequently, its potential recharge sites. The samples used for the stable isotope analysis (δ 18 O, δ 2 H) were measured using a GV-Isoprime isotope-ratio mass spectrometer at the Isotopy Laboratory of the Water Center for Latin America and the Caribbean. The δD of precipitation ranged between −110.20‰ and 10.11‰, with a mean of −55.67‰ ± 27.81‰. The δ 18 O ranged between −17.80‰ and 2.74‰, with a mean of −9.44‰ ± 4.74‰. The δD of groundwater ranged between −81.92‰ and −36.45‰, with a mean of −66.05‰ ± 8.58‰. The δ 18 O ranged between −18.26‰ and −8.84‰, with a mean of −12.35‰ ± 2.12‰. The local meteoric water line of the Zacatecas state is δD = −2.03 + 5.68 δ 18 O. The groundwater samples were clustered into four groups. The clustering of the samples led to the finding that streamflows play a significant role in the hydrological balance as a source of local recharge to the aquifer.

Environmental monitoring and assessment, 2017

The Monterrey metropolitan area (MMA) is the third greatest urban area and the second largest eco... more The Monterrey metropolitan area (MMA) is the third greatest urban area and the second largest economic city of Mexico. More than four million people living in this megacity use groundwater for drinking, industrial and household purposes. Thus, major ion and trace element content were assessed in order to investigate the main hydrochemical properties of groundwater and determine if groundwater of the area poses a threat to the MMA population. Hierarchical cluster analysis using all the groundwater chemical data showed five groups of water. The first two groups were classified as recharge waters (Ca-HCO3) coming from the foothills of mountain belts. The third group was also of Ca-HCO3 water type flowing through lutites and limestones. Transition zone waters of group four (Ca-HCO3-SO4) flow through the valley of Monterrey, whereas discharge waters of group 5 (Ca-SO4) were found toward the north and northeast of the MMA. Principal component analysis performed in groundwater data indicat...

Hydrological Processes, 2017

The quality of the groundwater supplying drinking water to the Guadalajara metropolitan area has ... more The quality of the groundwater supplying drinking water to the Guadalajara metropolitan area has deteriorated due to both endogenic and exogenic processes. Previous studies of this complex neotectonic volcanic environment suggest that the sources of contamination here are underground fluids derived from an active volcanic center and surface wastewater derived from regional land-use intensification. This study uses isotopic, gaseous, and chemical signatures to more comprehensively characterize this groundwater flow and its contamination paths. Groundwater is mainly recharged at the La Primavera Caldera to the west and is discharged into the Santiago River to the east. The exception to this trend is the Toluquilla area, where groundwater most likely represents rainfall originating from outside the basin limits. Evaporation affects groundwater in these areas, especially waters that have been affected by recycling below urban areas in the Atejamac area and by intensive agricultural activity in the Toluquilla area. Additionally, we present evidence that groundwater flow through alluvial sediments and tuffs in deeper wells mixes with a lower aquifer unit in basaltic-andesitic rocks, which are in contact with hydrothermal fluids. Groundwater ages range from postbomb in the western and northwestern regions of the study area (i.e., the Atemajac aquifer unit) to Late Pleistocene in the southern and southeastern regions (i.e., the Toluquilla aquifer unit). Recently recharged water records little mixing and is located mostly in or near the La Primavera volcanic system. As groundwater undergoes gravitational flow towards discharge areas, it mixes with older water components. Chloride and sodium concentrations above natural background levels are primarily related to volcanic activity, nitrate is associated with human activities, and sulfate originates from both anthropogenic sources and water-rock interactions. Nitrate originating from land-use activities (such as sewers, septic tanks, landfills, and agricultural fields) that is introduced into the deeper part of the groundwater system is expected to travel with the groundwater to the discharge areas because oxidizing conditions will prevent microbial reduction. See Supplementary Information.

Procedia Earth and Planetary Science, 2017

Chemical and isotopic data were used to explain the geochemistry and the hydrothermal influence i... more Chemical and isotopic data were used to explain the geochemistry and the hydrothermal influence in a groundwater system in Guadalajara, México. According to the measured parameters and the characteristics of the groundwater, four water groups were identified: i) thermal waters with high temperatures and high concentrations of Cl, Na, HCO 3 and the presence of Li, Mn, F and Mg, apparently of old age with a long residence time; ii) mixed waters of Na-HCO 3 to HCO 3 water type, which represent a mixture of cold water and thermal water; iii) polluted water characterized by high concentrations of nitrate and sulfate derived from urban and agricultural return flow; iv) cold water characterized by low temperature values, low concentration of Cl, Na and salinity, of Na-HCO 3 type. This last group represents modern water located in the recharge zone. Finally, major proportions of hydrothermal fluids are largest in the well waters of the first group varying from 1.9 to 12.5 %. The other groups show hydrothermal fractions below 1.7%. Groundwater with elevated hydrothermal proportions is located to the southeastern area of the Toluquilla aquifers. This study identifies some processes that govern the groundwater and hydrothermal mixing.

Procedia Earth and Planetary Science, 2017

The Monterrey Metropolitan Area (MMA) is the third greatest urban area of Mexico. Owing to the ra... more The Monterrey Metropolitan Area (MMA) is the third greatest urban area of Mexico. Owing to the rapid industrialization and urbanization of this city, more water resources are necessary in this semi-arid region. Thus, the objectives of this work were to characterize the chemical properties of groundwater supplied to MMA and to assess inter-annual variations in the water chemistry. Three groups of water were identified: recharge waters from mountain belts dominated by marine sedimentary rocks (Ca-HCO 3 type), transition zone waters from alluvial sediments (Ca-HCO 3-SO 4 type) and waters flowing through conglomerates and alluvial sediments of the northeastern MMA (Ca-SO 4 type). The ionic composition and the salinity gradient of each water group were in agreement with the topographic flow paths of the study area. The non-parametric Mann-Whitney U-test indicated that there have been no significant changes on the groundwater quality supplied to the MMA between the years 2006 and 2012.

Procedia Earth and Planetary Science, 2017

Coastal areas are attractive places for the establishment of urban settlements owing to the many ... more Coastal areas are attractive places for the establishment of urban settlements owing to the many benefits in terms of quality of life. An example of these areas is La Paz in Southern Baja California, Mexico, where demographic growth and agricultural activities under dry climatic conditions are threatening the availability of water resources. In recent years, an increasing salinity of groundwater has been identified, however, the origin of the salinity is not clear. Near the coastline, salt water intrusion is considered to be the main factor, while others play a role for increased salinities in the middle and upper aquifer zone. The study, using a hydrochemical tool analysis shows that the salinity of the coastline is the result of over-exploitation of wells, which increases saline intrusion resulting in a reverse cation exchange. It also indicates that the salinization of water in the recharge area is product of carbon dioxide dissolution and weathering of rock-forming silicate minerals, and in the central part result from cycling and use of fertilizer in agriculture.

Environmental Earth Sciences, 2016

Groundwater from the La Paz arid coastal aquifer in Baja California, Mexico, is essentially the o... more Groundwater from the La Paz arid coastal aquifer in Baja California, Mexico, is essentially the only source of drinking water for the local population and tourists, as well as irrigation water for agricultural needs. The intensive exploitation of the aquifer and water cycling has resulted in groundwater abatement (up to 10 m) and high salinity (up to *5800 mg l-1). A study using hydrochemistry, isotopic (deuterium, oxygen-18 and carbon-14) and gaseous tracers (chlorofluorocarbons CFC-11, CFC-12, CFC-113), as well as multivariate statistics, was developed to elucidate groundwater composition, flow and occurrence. Groundwater is of meteoric origin, and a large proportion is subject to evaporation. The primary natural recharge is generated in the El Novillo and Las Cruces ranges, and groundwater subsequently flows in a SE-NW direction toward the coast. The initial water type is the result of discordant dissolution of silicate minerals and ion exchange on soils. In the lower plain portion, the aquifer system is recharged from irrigation return flow and seawater intrusion, which significantly affects groundwater chemistry. Nitrate and chloride concentrations indicate that groundwater is highly affected by an overuse of fertilizers in agricultural activities, but there is little effect from urban activities. Seawater intrusion has progressed rapidly during the past decade, and the impact currently extends 13 km inland. Radiocarbon residence time calculations suggest that groundwater is modern, with the exception of Chametla and El Centerario sites in the central and western lowlands with ages of up to *5000 years. These waters indicate an additional recharge source for the upconing of fossil groundwater or regional flow.

Revista Internacional De Contaminacion Ambiental, Apr 1, 2011

Palabras clave: cuenca hidrológica, COP, atrazina y desetilatrazina, DDD y DDE RESUMEN En este es... more Palabras clave: cuenca hidrológica, COP, atrazina y desetilatrazina, DDD y DDE RESUMEN En este estudio se presenta el inventario de plaguicidas y una evaluación de la contaminación de agua y sedimentos en dos zonas agrícolas de México. Se analizaron plaguicidas triazínicos, fenoxiclorados y organoclorados, incluyendo seis contaminantes orgánicos persistentes (COP). Aunque el uso de atrazina ha sido prohibido y restringido en varias partes del mundo, en México este herbicida se sigue usando sin restricción alguna, los resultados obtenidos demuestran que afecta a la calidad del agua en una de las zonas agrícolas. Las concentraciones de atrazina y de su metabolito (desetilatrazina) en muestras de agua, rebasaron el límite para agua de consumo humano de 2 µg L-1 propuesto por la Organización Mundial para la Salud (WHO 2008) y el de la Comunidad Europea que establece un límite de 0.1 µg L-1 (European Parliament 1998). Los metabolitos del plaguicida DDT (DDD y DDE), excedieron el límite basal para calidad de sedimentos (ISQG por sus siglas en inglés) del criterio del Consejo de Ministros del Ambiente de Canadá para sedimentos en cuerpos de agua dulce, aunque no rebasan el límite de probable efecto (PEL por sus siglas en inglés) (CCME 2003). Aunque se restringió el uso de DDT en la agricultura en México (DOF 1991), los resultados muestran que los metabolitos de este plaguicida se continúan encontrando en muestras ambientales debido a su larga vida media. Se plantea la necesidad de vigilar mediante monitoreos en los cuerpos de agua, los plaguicidas encontrados en este estudio en concentraciones que exceden los criterios y límites establecidos.

Hydrology and Earth System Sciences Discussions, 2015