Jürgen Mahlknecht | Tecnológico de Monterrey (original) (raw)

Books and Chapters by Jürgen Mahlknecht

Water, energy, and food are essential for human well-being and for sustainable development. Water... more Water, energy, and food are essential for human well-being and for sustainable development. Water is required in almost all types of electricity generation and it is highly consumed in food production. Cities, industry, and crop production have increased their needs for water, energy and land resources, and at the same time, they are facing problems associated with the environmental degradation and, in some regions, resource scarcity. This paper proposes a multiobjective optimization model for the design of a water distribution network from a water− energy−food nexus point of view. Additionally, crop production and cost relationships are integrated to account for the water and energy requirements in the agricultural sector. The economic objective is the maximization of annual gross profit, which accounts for the water, energy and food production; the environmental objective establishes the minimization of overall greenhouse gas emissions, and the social objective is the maximization of the number of jobs. In this paper, because the objectives are opposites, a multistakeholder assessment is proposed in order to analyze and quantify the relationship of the water−energy−food nexus to assess synergies that improve the decision-making process. The mathematical model was applied to a case study located in the Sonoran Desert in Mexico, in which, a series of scenarios were solved to illustrate the capabilities of the proposed optimization approach. The results show strong trade-offs between the considered objectives as well as the quantification of the water−energy−food nexus.

, selección y edición del material; capítulos individuales, autores participantes. Los derechos d... more , selección y edición del material; capítulos individuales, autores participantes. Los derechos de los editores identificados como autores del material editorial y de los autores de los capítulos individuales han sido garantizados en conformidad con las secciones 77 y 78

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 indicates four principal components (PCs). PC1 included major ions Si, Co, Se, and Zn, suggesting that these are derived by rock weathering. Other trace elements such as As, Mo, Mn, and U are coupled in PC2 because they show redoxsensitive properties. PC3 indicates that Pb and Cu could be the less mobile elements in groundwater. Although groundwater supplied to MMA showed a high-quality, high mineralized waters of group 5 have NO3− concentrations higher than the maximum value proposed by international guidelines and SO42−, NO3−, and total dissolved solid concentrations higher than the maximum levels allowed by the Mexican normative.

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.

Approximately 80 per cent of the population of Latin America is concentrated in urban centres. Pr... more Approximately 80 per cent of the population of Latin America is concentrated in urban centres. Pressure on water resources and water management in cities therefore provide major challenges. Despite the importance of the issues, there has been little systematic coverage of the topic in book form.

This work fills a gap in the literature by providing both thematic overviews and case study chapters. It reviews key aspects of why water matters in cities and presents case studies on topics such as groundwater management, green growth and water services, inequalities in water supply, the financing of water services and flood management. Detailed examples are described from Argentina, Brazil, Colombia, Ecuador, Mexico and Peru, and there is also a chapter comparing lessons which might be learnt from US cities. Contributing authors are drawn from both within and outside the region, including from the Inter-American Development Bank, OECD and World Bank to set the issues in a global context.

El agua, como en todo el mundo, juega un papel primordial en la subsistencia y desarrollo de los ... more El agua, como en todo el mundo, juega un papel primordial en la subsistencia y desarrollo de los países latinoamericanos y caribeños. Es importante conocer el estado actual que guarda este recurso en la región como la condición de los cuerpos de agua, la infraestructura hidráulica, la demanda, disponibilidad, gestión, etc. Esta información es primordial ya que contribuye a la correcta planeación y gestión sostenible del recurso hídrico. Por lo tanto, la difusión de este conocimiento es esencial para el progreso de la región y del sector. La presente obra se basa en los objetivos del Centro del Agua para América Latina y el Caribe. Bajo este fundamento, recientemente el centro convocó a expertos en la materia de diferentes países de América Latina y el Caribe para realizar un diagnóstico de la situación hídrica de la región. A su vez, a otro grupo de expertos le fue encomendada la tarea de revisar los documentos a nivel editorial. Fue así que a cada país se le asignó un experto para desarrollar su diagnóstico con la intención de identifi car los principales datos de relevancia hídrica, incluyendo una descripción general y un directorio de los actores principales del sector. Los diagnósticos se estructuraron de acuerdo a ocho secciones generales:
1. Introducción: incluye datos básicos del país como sus aspectos geográficos y demográficos, indicadores económicos, grado de marginación, actividades económicas y huella hídrica.
2. Descripción general: comprende información general del país como su clima, precipitación, cuencas, corrientes principales, acuíferos y la distribución de sus actividades económicas dentro de su territorio.
3. Aguas superfi ciales: abarca la hidrografía del país, así como su infraestructura hidráulica, disponibilidad, red de monitoreo superfi cial y volúmenes superficiales utilizados.
4. Aguas subterráneas: engloba información acerca del nivel de explotación de los acuíferos del país, los volúmenes de agua subterránea utilizados, además de la disponibilidad y red de monitoreo del agua subterránea.
5. Calidad del agua y salud: contiene datos sobre la red de monitoreo superficial y subterránea de la calidad del agua, los resultados del monitoreo, las principales problemáticas del país en cuanto a la calidad del agua y salud, además de normas relacionadas y enfermedades hídricas que se han presentado.
xviii Prefacio
6. Usos del agua: dentro de esta sección se incluyen tópicos relacionados con los diversos usos del agua. Los usos del agua fueron agrupados en: uso urbano, industrial, agrícola, ecosistemas y otros usos.
7. Gestión: esta sección incluye los planes de desarrollo y programas nacionales, la participación de las organizaciones no gubernamentales, así como el marco legal y jurídico del sector, incluyendo las instituciones, normas, leyes y reglamentos vigentes.
8. Inversiones: comprende los planes de inversión del país, además de sus fuentes de financiamiento y los niveles de inversión del sector.
A partir de esta estructura se generaron diagnósticos de 19 países de la región. Además a modo de introducción, se incorporó un texto inicial en el que a manera general se proporciona un panorama del estado de los recursos hídricos del área. Esperamos que este, producto fi nal del proyecto, represente una importante contribución para difundir el conocimiento acerca del sector hídrico en nuestra región.

Scientific Papers by Jürgen Mahlknecht

The Sierra Madre Oriental (SMO) is composed of ranges with important regional geological structur... more The Sierra Madre Oriental (SMO) is composed of ranges with important regional geological structures in highly fractured carbonate rocks (Abra Formation), which facilitate the recharge of aquifers. At the regional scale, recharge occurs in the western SMO and locally, in ranges such as Palmillas, La Colmena and Abra, while the regional discharge is to the east in the Huasteca zone. Intermountain valleys, such as El Salto, are located near the regional discharge zone. Three end members were identified in these regions, one related to local flow, another to intermediate and a third to regional flow. These flows define ternary mixing processes in groundwater. In this paper, the evolution of groundwater is studied, which is important for learning the system performance and hydrogeochemical processes through VISHMOD (Virtual Samples in Hydrochemical Modeling) methodology. The mixing model for the intermountain valleys indicates that many recharges occur, for which local flow contributes 68.3%, intermediate flow 12.3% and regional flow 19.4%. The inverse modeling shows that the water-rock interaction, precipitation and/or dissolution of calcite, gypsum and dolomite are the main processes occurring in the aquifer system of the intermountain valleys.

With the increasing population, urbanization and industry in the arid area of Tecate, there is a ... more With the increasing population, urbanization and industry in the arid area of Tecate, there is a concomitant increase in contaminants being introduced into the Tecate River and its aquifer. This contamination is damaging the usable groundwater supply and making local residents and commercial enterprises increasingly dependent on imported water from the Colorado River basin. In this study we apply a suite of chemical and isotopic tracers in order to evaluate groundwater flow and assess contamination trends. Groundwater recharge occurs through mountain-block and mountain-front recharge at higher elevations of the ranges. Groundwater from the unconfined, alluvial aquifer indicates recent recharge and little evolution. The increase in salinity along the flow
path is due to interaction with weathering rock-forming silicate minerals and anthropogenic sources such as urban wastewater, residual solids and agricultural runoff from fertilizers, livestock manure and/or septic tanks and latrines. A spatial analysis shows local differences and the impact of the infiltration of imported waters from the Colorado River basin. The general trend of impaired water quality has scarcely been documented in the last decades, but it is expected to continue. Since the
groundwater system is highly vulnerable, it is necessary to protect groundwater sources.

This study addresses the changes in dissolved major and trace element concentrations along the Or... more This study addresses the changes in dissolved major and trace element concentrations along the Orinoco River, including the mixing zone between the Orinoco and Apure Rivers. Water samples from the Apure and Orinoco Rivers were collected monthly in four sectors over a period of 15 months. Auxiliary parameters (pH, dissolved oxygen, conductivity, and temperature), total suspended sediments, dissolved organic carbon (DOC), and major (Na, K, Ca, Mg, and Si) and trace (Al, Fe, Mn, Zn, Cu, and Cr) element concentrations were measured in all sectors. The relative contribution of both rivers after the Apure–Orinoco confluence was determined using Ca as a tracer. Moreover, a mixing model was developed to determine whether dissolved species exhibit a conservative behavior during mixing. The results indicate that DOC is removed from waters during the Apure–Orinoco mixing, probably due to absorption of DOC on mineral phases supplied by the Apure River. Dissolved Na, Ca, and Mg behave conservatively during the mixing processes, and their concentrations are controlled by a dilution process. The anomaly in the temporal pattern of K in the Orinoco is caused by the input of biogenic K originating from the Apure River during the high‐water stage. The loss of dissolved Si during the low‐water stage can be explained by the uptake of Si by diatoms. Dissolved Mn, Zn, Al, and Fe showed a non‐conservative behavior during the Apure–Orinoco mixing. The removal of Mn and Zn from the dissolved phase can be explained by the formation of Mn‐oxyhydroxides and the scavenging of Zn onto Mn oxides. Dissolved Fe is controlled by redox processes, although the removals of Fe and Al due to the preferential adsorp-tion of large organometallic complexes by mineral surfaces after the Apure–Orinoco confluence can affect the mobility of both elements during transport. The conservative behavior shown by Cu and Cr can be related to the tendency of both elements to be complexed with small organic colloids, which are not preferentially adsorbed by clays.

Mexico is exposed to droughts and vulnerable to their impacts. Despite a history of serious econo... more Mexico is exposed to droughts and vulnerable to their impacts. Despite a history of serious economic and social consequences from drought, until recently national water policy did not acknowledge this type of natural disaster as a priority issue. This paper analyses how drought policy in Mexico has evolved since the creation of the National Water Commission in 1989 up to 2013, when the most specific initiative in that regard was introduced: the National Drought Program (Programa Nacional Contra la Sequía, PRONACOSE). Over that period of time drought has slowly but steadily gained importance in national water planning and management. Significant initiatives have been implemented, including a national drought early warning and monitoring system. Nevertheless, efforts still focus on compensating economic losses after the fact and little has been achieved in terms of reducing the country's vulnerability to drought. There is a great need to increase public awareness and boost the scientific knowledge necessary for the design of appropriate preventive measures. A long way remains to establish an effective , forward-looking, integrated and preventive drought management model.

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 car- bon-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 sea- water 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 Cha- metla 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.

Groundwater chemistry and isotopic data from 40 production wells in the Atemajac and Toluquilla v... more Groundwater chemistry and isotopic data from 40 production wells in the Atemajac and Toluquilla valleys, located in and around the Guadalajara metropolitan area, were determined to develop a conceptual model of groundwater flow processes and mixing. Stable water isotopes (δ2H, δ18O) were used to trace hydrological processes and tritium (3H) to evaluate the relative contribution of modern water in samples. Multivariate analysis including cluster analysis and principal component analysis were used to elucidate distribution patterns of constituents and factors controlling groundwater chemistry. Based on this analysis, groundwater was classified into four groups: cold groundwater, hydrothermal groundwater, polluted groundwater and mixed groundwater. Cold groundwater is characterized by low temperature, salinity, and Cl and Na concentrations and is predominantly of Na-HCO3-type. It originates as recharge at "La Primavera" caldera and is found predominantly in wells in the upper Atemajac Valley. Hydrothermal groundwater is characterized by high salinity, temperature, Cl, Na and HCO3, and the presence of minor elements such as Li, Mn and F. It is a mixed-HCO3 type found in wells from Toluquilla Valley and represents regional flow circulation through basaltic and andesitic rocks. Polluted groundwater is characterized by elevated nitrate and sulfate concentrations and is usually derived from urban water cycling and subordinately from agricultural return flow. Mixed groundwaters between cold and hydrothermal components are predominantly found in the lower Atemajac Valley. Twenty-seven groundwater samples contain at least a small fraction of modern water. The application of a multivariate mixing model allowed the mixing proportions of hydrothermal fluids, polluted waters and cold groundwater in sampled water to be evaluated. This study will help local water authorities to identify and dimension groundwater contamination, and act accordingly. It may be broadly applicable to other active volcanic systems on Earth.

In this work, the biocatalytic ability of laccases from filtered culture supernatant of Pycnoporu... more In this work, the biocatalytic ability of laccases from filtered culture supernatant of Pycnoporus sanguineus was evaluated without mediators and under mild reaction conditions. This 100 U L −1 laccase cocktail removed 50% Diclofenac, 97% β-Naphthol and 71% 2,4 Dichlorophenol within 8 h of reaction and 78% for 5,7-Diiodo-8-hydroxyquinoline within 3.5 h; at initial concentrations of 10 mg L−1 and at 25 °C. Furthermore, this enzyme cocktail also removed in excess of 53% all tested compounds in a real groundwater sample from northwestern Mexico. In comparison with purified laccases, the use of cocktail offers operational advantages since additional purification steps can be avoided.

The biodegradation of organic compounds present in water at trace concentration has become a crit... more The biodegradation of organic compounds present in water at trace concentration has become a critical environmental problem. In particular, enzymatic oxidation by fungal laccases offers a promising alternative for efficient and sustainable removal of organic pollutants in water. In this work, the biocatalytic ability of laccases from the Pycnoporus sanguineus CS43 fungus was evaluated. A filtered culture supernatant
(laccase cocktail) evidenced an enhanced biotransformation capability to remove common endocrinedisruptor compounds (EDCs), such as bisphenol A, 4-nonylphenol, 17-α ethynylestradiol and triclosan. A biodegradation of around 89–100 % was achieved for all EDCs using synthetic samples (10 mg L−1) and after the enzymatic treatment with 100 U L−1 (50.3 U mg −1). The biodegradation rates obtained were fitted to a first
order reaction. Furthermore, enzymatic biocatalytic activity was also evaluated in groundwater samples coming from northwestern Mexico, reaching biotransformation percentages between 55 and 93 % for all tested compounds. As far as we know this is the first study on real groundwater samples in which the enzymatic degradation of target EDCs by a laccase cocktail from any strain of Pycnoporus sanguineus was evaluated. In comparison with purified laccases, the use of cocktail offers operational advantages since additional purification steps can be avoided.

Zona Citrícola is an important area for Mexico due to its citriculture activity. Situated in a su... more Zona Citrícola is an important area for Mexico due to its citriculture activity. Situated in a sub-humid to humid climate adjacent to the Sierra Madre Oriental, this valley hosts an aquifer system that represents sequences of shales, marls, conglomerates, and alluvial deposits. Groundwater flows from mountainous recharge areas to the basin-fill deposits and provides base flows to supply drinking water to the adjacent metropolitan area of Monterrey. Recent studies examining the groundwater quality of the study area urge the mitigation of groundwater pollution. The objective of this study was to characterize the physical and chemical properties of the groundwater and to assess the processes controlling the groundwater’s chemistry. Correlation was used to identify associations among various geochemical constituents. Factor analysis was applied to identify the water’s chemical characteristics that were responsible for generating most of he variability within the dataset. Hierarchical cluster analysis was employed in combination with a post-hoc analysis of variance to partition the water samples into hydrochemical water groups: recharge waters (CaHCO3), transition zone waters (Ca-HCO3-SO4 to Ca-SO4-HCO3) and discharge waters (CaSO4). Inverse geochemical models of these groups were developed and constrained using PHREEQC to elucidate the chemical reactions controlling the water’s chemistry between an initial (recharge) and final water. The primary reactions contributing to salinity were the following: (1) water-rock interactions, including the weathering of evaporitic rocks and dedolomitization; (2) dissolution of soil gas carbon dioxide; and (3) input from animal/human wastewater and manure in combination with by denitrification processes. Contributions from silicate weathering to salinity ranged from less important to insignificant. The findings suggest that it may not be cost-effective to regulate manure application to mitigate groundwater pollution.

Renewable and Sustainable Energy Reviews, Apr 1, 2014

Mexico ranks 9th in the world in crude oil reserves, 4th in natural gas reserves in America and i... more Mexico ranks 9th in the world in crude oil reserves, 4th in natural gas reserves in America and it is also highly rich in renewable energy sources (solar, wind, biomasss, hydropower and geothermal). However, the potential of this type of energy has not been fully exploited. Hydropower is the renewable energy source with the highest installed capacity within the country (11,603 MW), while geothermal power capacity (958 MW) makes Mexico to be ranked 4th in the use of this energy worldwide. Wind energy potential is concentrated in five different zones, mainly in the state of Oaxaca, and solar energy has a high potential due to Mexico's ideal location in the so called Solar Belt. Biomass energy has the highest potential (2635 to 3771 PJ/year) and has been the subject of the highest number of research publications in the country during the last 30 years (1982–2012). Universidad Nacional Autonoma de Mexico has led research publications in hydropower, wind, solar and biomass energy and Instituto de Investigaciones Electricas in geothermal energy during this period. According to the General Law for Climate Change the country has set the goal of generating 35% of its energy needs from renewable sources by 2024. This paper presents an overview of the renewable energy options available in Mexico, current status, main positive results to date and future potential. It also analyses barriers hindering improvements and proposes pertinent solutions.

Science of the Total Environment, 2014

Nitrate isotopic values are often used as a tool to understand sources of contamination in order ... more Nitrate isotopic values are often used as a tool to understand sources of contamination in order to effectively
manage groundwater quality. However, recent literature describes that biogeochemical reactions may modify
these values. Therefore, data interpretation is difficult and often vague. We provide a discussion on this topic
and complement the study using halides as comparative tracers assessing an aquifer underneath a sub-humid
to humid region in NE Mexico. Hydrogeological information and stable water isotopes indicate that active
groundwater recharge occurs in the 8000km2 study area under present-day climatic and hydrologic conditions.
Nitrate isotopes and halide ratios indicate a diverse mix of nitrate sources and transformations. Nitrate sources
include organic waste and wastewater, synthetic fertilizers and soil processes. Animal manure and sewage
from septic tanks were the causes of groundwater nitrate pollution within orchards and vegetable agriculture.
Dairy activities within a radius of 1000m from a sampling point significantly contributed to nitrate pollution.
Leachates from septic tanks caused nitrate pollution in residential areas. Soil nitrogen and animal waste were
the sources of nitrate in groundwater under shrubland and grassland. Partial denitrification processes helped
to attenuate nitrate concentration underneath agricultural lands and grassland, especially during summer
months.

Environmental Earth Sciences, 2011

Chemical compositions and stable isotope ratios of water and sulphate were used to characterise s... more Chemical compositions and stable isotope ratios of water and sulphate were used to characterise sources and processes responsible for elevated concentrations of sulphate and other constituents in groundwater from aquifers at Colima State along Mexico’s Pacific Coast. The δ18O and δ2H values of the groundwater were similar to those of precipitation indicating a meteoric origin, and recharge processes are relatively uniform in large parts of the study area with only slight local evaporation effects. δ34Ssulphate and δ18Osulphate analyses indicated that high sulphate concentrations of up to 1,480 mg/l are mainly due to dissolution of evaporites and volcanic exhalations. Chloride is largely related to sources other than seawater. The Marabasco sub basin is affected by anthropogenic contamination through manganese and iron ore mining activities. The obtained knowledge regarding sources and areas of contamination will be essential for the development and design of a water quality monitoring program in the study area.

National Groundwater Association Summit 2013 Abstracts, Apr 29, 2013

We used environmental tracers (CFCs, 18O, 2H, 3H, 14C, and water chemistry) to analyze the ground... more We used environmental tracers (CFCs, 18O, 2H, 3H, 14C, and water chemistry) to analyze the groundwater quality and flow system underlying and supplying part of the Metropolitan Area of Guadalajara, México. Most of the samples showed isotopic signatures, indicating recharge from local meteoric precipitation. Significant tritium concentrations were interpreted as a clear sign that groundwater was a mixture from water prior to 1952 and post 1960, which indicates that precipitation from the last years contributed significantly to groundwater recharge. CFCs revealed apparent recharge from 1960 to 1980. 14C results indicated groundwater aging approximately between 10,000 and 12,000 for the northern portion (Atemajac), and >20,000 years BP for the southern portion (Toluquilla). Comparison of CFCs, 3H and 14C concentrations proves that the samples are a mixture of waters from different ages. Additionally, zones with aquifer temperatures higher than 30°C were identified, suggesting the presence of chemical elements associated to geothermal sources.

Environmental Monitoring and Assessment, 2017

Renewable and Sustainable Energy Reviews, Apr 1, 2014

Science of the Total Environment, 2014

Environmental Earth Sciences, 2011

National Groundwater Association Summit 2013 Abstracts, Apr 29, 2013

Hydrological Processes, 2008

The Chihuahua City region, located in the semiarid-arid northern Highlands of Mexico, has experie... more The Chihuahua City region, located in the semiarid-arid northern Highlands of Mexico, has experienced intensive groundwater abstraction during the last 40 years to meet water demands in the region. A 15 geochemical survey was carried out to investigate the evolution from baseline to modern conditions of a 130-km flow path including the El Sauz-Chihuahua-Aldama-San Diego de Alcalá regions. The research approach included the use of major chemical elements, chlorofluorocarbons and environmental isotope ( 18 O, 2 H, 13 C and 14 C) tracers. Stable isotopes indicate that groundwater evolves from the evaporation of local rainfall and surface water. Groundwater located at the lower end of the flow section is up to 6,000 yr 20 old and older groundwater in the order of 9,000 yr BP was found in a deep well located in the upper part of the flow system, implying contribution from a neighbour basin. The background groundwater chemistry upstream of Chihuahua City, results from feldspar weathering. Beyond Chihuahua City the chemical conditions are strongly modified due to disposal of sewage from public and industrial water supply into the Rio Chuviscar, subsequent allocation of this water to agricultural irrigation areas and direct infiltration 25 under the river bed. In consequence, anions like chloride and sulphate are mainly related to surface sources.

Isotopes in Environmental and Health Studies, 2007

Environmental Earth Sciences, 2006

Vulnerability maps are important tools for water decision makers and land-use planners for protec... more Vulnerability maps are important tools for water decision makers and land-use planners for protection of aquifers against contamination. The vulnerability map, according to the parametric method SINTACX for assessing intrinsic aquifer vulnerability, was validated in a case study with chlorofluorocarbon tracer technologies (CFC-11, CFC-12, and CFC-113) of groundwater. The tested area was the 1,295 km 2 volcano-sedimentary area of San Miguel de Allende, Mexico. From the results of this area, it appears that the vulnerability map is in parts inconsistent with the underlying groundwater flow system. Thus, the vulnerability map was corrected with tracer information. The validated vulnerability map indicates that the degree of vulnerability varies from low 1 Corresponding author Mahlknecht et al., 2006, Env. Geol. (author's version) 2 | P a g e to moderate-high. Low vulnerability values are found in the graben extending from north to south along the San Miguel de Allende fault system and high values in recharge areas southeast and northwest of the study area. The investigation is a demonstration that the scientific reliability of results of the parametric method can be improved by validation with tracer techniques representing the groundwater dynamics. The flexible structure of SINTACX allows revising and adjusting scores and weights of the parameter maps to rebuild a new vulnerability map consistent with the hydrological system.

Journal of Hydrology, 2006

The Independence Basin in the semi-arid Guanajuato state of central Mexico is facing serious grou... more The Independence Basin in the semi-arid Guanajuato state of central Mexico is facing serious groundwater resources deficiency due to an increasing demand linked to a rapid population growth and agricultural development. This problem is aggravated by an inadequate evaluation of groundwater resources in the region. Geochemistry and isotopic tracers were used in order to investigate the groundwater flow system and estimate the groundwater residence time. The groundwater is characterized by low salinity with some exceptions associated to a contribution of more saline groundwater from deep formations. The predominant reactions are CO 2 gas dissolution, carbonate dissolution, albite weathering, kaolinite and chalcedony precipitation. Six principal hydrochemical zones were recognized, which provided information on plausible recharge sources and groundwater chemical evolution. The 14 C concentration varies between 19 and 94 pmc. The high 14 C values indicating recent recharge are observed at the basin margins and a trend to lower 14 C values is observed along the modern groundwater flow paths. The groundwater residence time according to radiocarbon estimations ranges between recent and ~11 ka. The residence time distribution matches the regional important discharge zones west in the basin center (from Dolores Hidalgo and southwest from Doctor Mora). Hydrochemical tracers are in general agreement with the predeveloped and current hydraulic-head configuration however show some inconsistencies with the predeveloped head in the downgradient areas, which means that the impact by gradually increasing groundwater extraction during the last decades is reflected on radiocarbon age distribution. Geochemical evidences imply that the recharge input from the northern basin area is insignificant.

Journal of Arid Environments, 2005

This study was carried out in the Cuenca de la Independencia, a semi-arid basin in Central Mexico... more This study was carried out in the Cuenca de la Independencia, a semi-arid basin in Central Mexico. The objective is to describe the main features of a groundwater flow regime under natural conditions, based on groundwater discharge manifestations. Information obtained from paleoecological, paleontological, archaeological and historical data suggests that, prior to heavy development (starting in the 1950s), the hydrogeologic regime was characterized by a larger groundwater availability in a more humid and colder climate. Manifestations associated to groundwater discharges are springs, lagoons, wetlands, saline soils, chalcedony deposits, phreatophytes, thermalism, and artesianism. The different types of manifestations and their position in the basin indicate the influence of groundwater flow systems hierarchically nested, forming concentric zones at ground level. The groundwater flow regime corresponds to a classical gravity-induced flow system with generation of local, intermediate and regional patterns. Integrating several types of data to establish the flow geometry and its dynamics has proven a useful tool to increase understanding of the original groundwater regimes. This approach can also be applied in other over-exploited semi-arid basins.

Environmental Earth Sciences, 2004

In the light of progressive depletion of groundwater reservoir and water quality deterioration of... more In the light of progressive depletion of groundwater reservoir and water quality deterioration of the Independence aquifer, an investigation on chemical data of dissolved major and minor constituents in 246 recent groundwater samples was performed. The main objective was the detection of processes responsible for the geochemical evolution and mineralization throughout the area. Multivariate techniques revealed different sources of solutes (a) dissolution of calcium and magnesium carbonate minerals, (b) weathering of acid volcanic minerals, (c) alteration of manganese containing alkaline silicates, (d) leaching of halite deposits of meteoric origin, (e) contamination from agricultural and urban wastewaters, and (f) evaporative effects due to intensive irrigation. Although nitrate contamination is associated with pollution from intensive cultivated areas, natural contamination plays an important role in the study area. The investigation reveals that weathering of acid volcanic rocks (rhyolite) and oxidation of arsenic bearing sulfide minerals are the responsible processes for high fluorine (up to 16 mg/l) and arsenic (up to 0.12 mg/l) contents, respectively, exceeding the Mexican maximum admissible concentration for drinking water. Except for kaolinite, all recharge processes are dissolution oriented (CO2, calcite, dolomite, K-feldspar, plagioclase). Silicate precipitation (amorphous silica and chalcedony) is of growing importance in discharge zones. Cation exchange is not an important issue in the whole study area.

In coastal zones, groundwater overexploitation reduces freshwater outflow to the sea and causes s... more In coastal zones, groundwater overexploitation reduces freshwater outflow to the sea and causes seawater to migrate toward fresh groundwater resources, increasing salinity in groundwater reservoirs. This seawater intrusion is among the world's leading causes of groundwater pollution, as salty water can affect safe drinking consumption, food production, and ecosystem services. To explore this and others contaminations sources, cluster analysis has been used for decades to aid in water resource pattern recognition in coastal aquifers around the world. This work shows how cluster analysis has been applied for seawater intrusion pattern recognition in coastal zonas around the world between 2000 and 2022 through a systematic review based on the PRISMA statement. After the searching and selection stages, it was carried out the bibliometric analysis of the 81 identified studies. Furthermore, it was discussed information about the number of samples, number of variables, redundant variab...

ISEE Conference Abstracts

Environment International

Journal of Environmental Management, 2022

A literature review was carried out to analyze the current status of microplastic research in Lat... more A literature review was carried out to analyze the current status of microplastic research in Latin America and the Caribbean (LAC). Specifically, this work focused on publications pertaining to (1) occurrence and distribution of microplastics in the environment, including water, sediments, and soil and (2) the environmental impact of MPs, particularly their presence and effects on aquatic and terrestrial organisms. The review included peer-reviewed articles from Scopus, Science Direct, Web of Science, Google Scholar and two iberoamerican open access databases (Redalyc and SciELO). It was found that LAC has only contributed to 5% of the global scientific output on microplastics, and overall the highest contributor within the region was Brazil (52%), followed by Chile (16%) and Mexico (13%). An additional section analyzing the barriers to conducting microplastic research in LAC and their exacerbation by the current COVID-19 pandemic was included to provide additional context behind the relatively low scientific production and improve recommendations encouraging research in this region.

Environmental Geochemistry and Health, 2022

The thermal mineral water of Peñón de los Baños spa (Mexico City) has been used for over 500 year... more The thermal mineral water of Peñón de los Baños spa (Mexico City) has been used for over 500 years starting in pre-Hispanic times and is famous for the treatment of various pathologies. It has a temperature of 45 °C, which is rich in HCO3−, and its main trace elements are B, Li and Fe, which confers healing effects. Concerns about the sustainability of this important spa have motivated this study to understand the thermal system, possible hydraulic and hydrochemical changes over time and its implications. Stable water isotope data indicate that the thermal water sources originate from local precipitation at Sierra de las Cruces with a recharge elevation of approximately 2770 m above sea level. The recharged water percolates through volcanic and carbonate rock formations and ascends via fault structure conduits, where it eventually is extracted 25 km downstream in Peñon de los Baños. During the gravity-driven deep circulation of up to 4.9 km, the groundwater is heated up to 136–160 °C. A comparison of past and current water levels and water chemical analyses indicates a water table drop and few variations in the chemical composition, confirming the presence of anthropic impact on water quality. Due to the heavy groundwater extractions in Mexico City, the spring water flow has ceased, and water must be pumped now from a 203-m deep well. In addition, the concentration of bicarbonate, sodium and chloride has been reduced by half since the onset of groundwater development. The therapeutic effects of this thermal mineral water are at risk due to the alteration of the chemical signature. However, new and different therapeutical uses may prevent a future deterioration or closure of this historically important thermal spa. It is crucial to establish a monitoring program of the thermal mineral water and reducing or minimizing nearby urban extractions which tap the regional flow component to preserve the properties of the thermal water.

Water Research, 2021

Due to global warming and local anthropogenic pressures, sustainable groundwater resource exploit... more Due to global warming and local anthropogenic pressures, sustainable groundwater resource exploitation in coastal cities is increasingly threatened. For example, the fifth largest Brazilian city, Recife, is considered as a representative hot spot for these issues and illustrates the great challenges facing many urban areas in the southern hemisphere. There, recharge as well as surface water and groundwater quality are altered by frequent droughts and poorly planned environmental management since decades. To maintain access to water, thousands of private wells were dug in order to pump water from the multi-layered aquifer system found under the city. This massive exploitation is causing a chronic lowering of the water levels, as well as seawater intrusion and contaminations by wastewater or polluted surface waters. Through hydrochemical characterization, mainly Cl/Br ratio and Cl concentrations, of wells sampled throughout the metropole, this study first characterizes the main environmental impacts on the resource, i.e. waste waters and seawater. Combining this evaluation with lithological, land-use and socio-environmental data, it was then possible to build decision trees identifying combinations of multiple factors possibly having an impact on contamination types. The well and population densities, the waste and sewage management, as well as the absence of sanitary facilities in houses appeared as critical parameters to target in order to reduce the risk of contamination of the water resource and ensure its preservation. Based on these factors, we created a risk map for contamination types that should help in identifying areas where groundwater resource may present an environmental (and then health) issue for people. Besides, this study shows that the combination of hydrochemical, geomorphological and socio-environmental characterizations of these urban systems featuring very contrasted situations between neighborhoods is a relevant tool to propose further groundwater management strategies.

Environmental Science and Pollution Research, 2021

Environmental Pollution, 2021

Estimation of nitrate pollution sources and transformations in groundwater of an intensive livest... more Estimation of nitrate pollution sources and transformations in groundwater of an intensive livestock-agricultural area (Comarca Lagunera), combining major ions, stable isotopes and MixSIAR model, Environmental Pollution,

Environmental Science and Pollution Research, 2021

The imminent arrival of nanoparticles (NPs) to the wastewater treatment plants (WWTP) brings conc... more The imminent arrival of nanoparticles (NPs) to the wastewater treatment plants (WWTP) brings concern about their effects. In this work, the effects of titanium dioxide (TiO 2) NPs in the removal of carbon, nitrogen, and phosphorus by activated sludge bioreactors during the treatment of synthetic, raw and ltered wastewater were evaluated. The oc size, compaction of sludge, and morphological interactions between sludge and NPs were also evaluated. The main effect was observed in the ammoniacal nitrogen removal, which was inhibited up to 22% for all types of wastewater in the presence of TiO 2 NPs. While nitrite production de ciencies were observed for real wastewaters experiments, nitrate formation was mainly affected for synthetic wastewater. The removal of organic matter was affected by TiO 2 NPs in lower level (up to 6%) than nitrogen removal, especially during treatment of raw wastewater. The removal of orthophosphate was improved in presence of NPs 34%, 16% and 55% for synthetic, raw, and ltered wastewater, respectively. The compaction of the sludge was also a positive effect, which enhanced as the concentration of NPs increased without alterations in the oc size for all types of wastewater. Based on TEM and STEM imaging, the main interaction of TiO 2 NPs with activated sludge ocs was mainly the adsorption of NPs on the cell membrane. This means that NPs can disrupt the cell membrane during aerobic wastewater treatment. The effects of NPs on macronutrient removal depended on wastewater characteristics. The use of realistic matrices is highly encouraged for ecotoxicological experiments.

Applied Sciences, 2021

Experts confirm that 85% of the world’s population is expected to live in cities by 2050. Therefo... more Experts confirm that 85% of the world’s population is expected to live in cities by 2050. Therefore, cities should be prepared to satisfy the needs of their citizens and provide the best services. The idea of a city of the future is commonly represented by the smart city, which is a more efficient system that optimizes its resources and services, through the use of monitoring and communication technology. Thus, one of the steps towards sustainability for cities around the world is to make a transition into smart cities. Here, sensors play an important role in the system, as they gather relevant information from the city, citizens, and the corresponding communication networks that transfer the information in real-time. Although the use of these sensors is diverse, their application can be categorized in six different groups: energy, health, mobility, security, water, and waste management. Based on these groups, this review presents an analysis of different sensors that are typically ...

Science of The Total Environment, 2021

A last ten years review about the status of the Atoyac River was performed. • Urban area waters r... more A last ten years review about the status of the Atoyac River was performed. • Urban area waters reached the strongly contaminated classification according to WQI. • Total coliforms in river waters reached values of up to 10 12 MPN/100 mL. • Sediments are enriched in S,

This study is the first focused on the presence of SARS-CoV-2 in different freshwater environment... more This study is the first focused on the presence of SARS-CoV-2 in different freshwater environments in an urban setting. Groundwater and surface water reservoirs for drinking water as well as water from receiving rivers of the Monterrey Metropolitan Area were sampled repeatedly during a SARS-CoV-2 peak phase between October 2020 and January 2021, and viral RNA was measured by quantitative reverse transcription polymerase chain reaction. Forty-four percent of the groundwater samples had detectable viral loads between 2.6 and 38.3 copies/ml. A significant correlation between viral load and sucralose concentration in groundwater reaffirmed the hypothesis of leaching and infiltrating effluent from surface and/or failing sewage pipes and emphasized the importance of water disinfection. Twelve percent of the surface water dam samples tested positive for viral RNA, with values varying between 3.3 and 3.8 copies/ml. Finally, 13% of the river samples were positive for viral RNA, with concentr...

Journal of Contaminant Hydrology, 2020

This study analyzed the dynamics of major ions and trace elements along the groundwater flow path... more This study analyzed the dynamics of major ions and trace elements along the groundwater flow path of the coastal sedimentary Todos Santos aquifer in Baja California Sur, Mexico, moderately impacted by anthropogenic activities. The results indicate that the elements Ca 2+ , Mg 2+ , Ba 2+ , Sr 2+ and Li + are mobilized from the aquifer matrix during seawater intrusion, whereas the alkali-elements Na + , K + and Rb + are removed from solution, possibly due to cationic exchange process. The anions HCO 3and SO 4 2− and the elements I and B are mobilized due to carbonate mineral weathering, whereas dissolved silica and the halides Br − and F − behave conservatively during salinization. Groundwater NO 3 − is provided by sewage infiltration. Regarding trace elements behavior, we identify three groups: i) elements that are mobilized during saline intrusion (Fe, Co, V, Se, Re), ii) elements revealing low or no mobilization (Mo, Ni, Cr, Ta, W) and iii) elements that show an undefined tendency (U, As, Ge, Sb, Cu, Mn). The U and NO 3 − levels in groundwater should be considered carefully because several wells have concentrations close to the permissible levels. This study may be useful as reference for knowing the possible effect of salinization in coastal aquifers under sea level rise scenarios driven by climate change. −. In addition to ionic exchange processes, other geochemical

Environmental Earth Sciences, 2020

The Nubian Sandstone Aquifer (NSA) has been the main source of water in the western desert of Egy... more The Nubian Sandstone Aquifer (NSA) has been the main source of water in the western desert of Egypt since 1985. This aquifer is subject to excessive groundwater withdrawal in the region, causing declines in potentiometric heads and a deterioration of groundwater quality. Consequently, investigations were undertaken to provide baseline water quality information for groundwater management. Water quality data from wells in the study area were manipulated using a Geographic Information System (GIS), statistical analyses (SPSS), graphical simulations (such as Piper and Gibbs diagrams), water quality index (WQI) and a simple geochemical model (NETPATH). This assessment and the use of hydrochemical indices indicated that chemical reactions between the aquifer matrix and groundwater are likely to be the main factors controlling the chemical composition of groundwater in the area. Also, the results of WQI showed that the majority of the collected water points (about 89%) were unsuitable for potable use due to elevated iron concentrations. The NETPATH modeling results suggest that dedolomitization, silicate weathering and dissolution of halite processes are the main geochemical processes that influence changes in the chemical composition along groundwater flow-paths.

$Research paper thumbnail of Hydrological control, fractionation, and fluxes of dissolved rare earth elements in the lower Orinoco River, Venezuela$

Applied Geochemistry, 2019

The monthly variation of dissolved rare earth elements (REEs) was assessed in the lower Orinoco R... more The monthly variation of dissolved rare earth elements (REEs) was assessed in the lower Orinoco River during a two year period (2007-2008) to determine the seasonal variability of REE concentrations, to identify the variables that exert the main control in their concentrations and fractionation, and to quantify the annual fluxes of dissolved REEs to the Orinoco estuary. Overall, the abundance of dissolved REEs is dominated by hydrological variations in the water discharge, wherein the lowest concentrations and greater fractionation occur during low water-discharge periods. The pH and Al-and Fe-mineral colloids are identified as the main variables that control both the abundance and fractionation of dissolved REEs. An enrichment of heavy REEs (HREEs) relative to light REEs (LREEs) occurs at circumneutral and alkaline pH values. However, the logarithmic relationships between the Yb UCC /Nd UCC ratios and Al and Fe concentrations indicate that Al-and Fe-mineral colloids are responsible for the progressive enrichment of LREEs relative to HREEs under acidic conditions. The Ce and Eu anomalies are also dominated by variations in the water discharge. Negative Ce-anomalies are observed during low flow periods. This is probably due to the signature of the Andean host rocks and/or the oxidation and co-precipitation of Ce (III) to CeO 2 at alkaline pH. However, the lesser Ce fractionated values during flood/high-water periods may indicate less oxidized/more reduced source conditions during these periods. Conversely, positive Eu anomalies are observed during low-water periods because of the preferential weathering of plagioclase in shield terranes and Eu-bearing minerals in the Andes. The fluxes of dissolved REEs from the lower Orinoco River to the Orinoco estuary display strong inter-annual variations, which range from 45.6% for Lu to 56.5% for Gd. These results highlight the importance of performing monthly and inter-annual REE time series in order to develop a more precise quantification of the annual REE fluxes from large rivers to the oceans.

Environmental Earth Sciences, 2019

The construction of the 42-km long All-American Canal in southern California (USA) near the borde... more The construction of the 42-km long All-American Canal in southern California (USA) near the border with Mexico in the 1940s generated infiltration which raised groundwater levels in the area inducing groundwater to flow into the Mexicali Valley aquifer (Mexico). In the late 2000s, the USA started a controversial lining project to reduce infiltration below the canal, with far-reaching consequences. This investigation implemented a numerical groundwater flow model to determine the hydrodynamic effects of the lining of the All-American Canal on the Mexicali Valley aquifer. For this purpose, plenty of information was acquired with a 32-year span of data and 88 monitoring wells in the area of interest. Field evidences and the model approach suggest that seepage from the All-American Canal resulted in the rise of groundwater levels to 14 m in the northern Mexicali Valley aquifer. However, continuous drawdowns were observed after concluding the lining in 2008, with the result of a drop in the water table to 5.8 m after 4 years of monitoring. A forecast shows that groundwater levels will tend to stabilize to those levels that existed prior to the infiltration produced by the canal. At the existing wetlands in the Mesa de Andrade in Mexico, a 1-m drawdown will be registered due to the lining, which could affect the existing ecosystem. Any additional extraction done on the Mesa de Andrade will likely dry the wetland.

ACS Sustainable Chemistry & Engineering, 2018

Water, energy, and food are essential for human well-being and for sustainable development. Water... more Water, energy, and food are essential for human well-being and for sustainable development. Water is required in almost all types of electricity generation and it is highly consumed in food production. Cities, industry, and crop production have increased their needs for water, energy and land resources, and at the same time, they are facing problems associated to the environmental degradation and, in some regions, resource scarcity. This paper proposes a multi-objective optimization model for the design of a water distribution network from a water-energy-food nexus point of view. Additionally, crop production and cost relationships are integrated to account for the water and energy requirements in the agricultural sector. The economic objective is the maximization of annual gross profit, which accounts for the water, energy and food production; the environmental objective establishes the minimization of overall greenhouse gas emissions, and the social objective is the maximization of the number of jobs. In this paper, since the objectives are opposites, a multi-stakeholder assessment is proposed in order to analyze and quantify the relationship of the water-energy-food nexus to assess synergies that improve the decision-making process. The mathematical model was applied to a case study located in the Sonoran Desert in Mexico, in which, a series of scenarios were solved to illustrate the capabilities of the proposed optimization approach. The results show strong trade-offs between the considered objectives as well as the quantification of the water-energy-food nexus.

Journal of Environmental Chemical Engineering, 2018

The increasing presence of chemicals and pharmaceuticals in rivers, lakes and groundwater among o... more The increasing presence of chemicals and pharmaceuticals in rivers, lakes and groundwater among others, represents a latent threat both to ecosystems and to human health. Conventional treatment methods for water hardly eliminate these pollutants, which are usually dissolved in low concentrations (µgL-1 or ngL-1). Therefore, the use of nanomaterials represents a viable alternative to

Inter-American Development Bank, 2018

Existen pocas publicaciones sobre el agua y el desarrollo urbano en América Latina. Este libro bu... more Existen pocas publicaciones sobre el agua y el desarrollo urbano en América Latina. Este libro busca llenar el vacío conceptual y operacional existente sobre los vínculos entre el agua, la urbanización y el desarrollo sostenible en el contexto latinoamericano. El contenido está principalmente basado en la experiencia y las lecciones aprendidas del contexto específico de las ciudades latinoamericanas. El libro ha sido escrito teniendo en mente diferentes audiencias: principalmente, los responsables de la toma de decisiones y la planeación en el sector público, los profesionales que trabajan en el sector del agua y en temas relacionados con el sector en todo el mundo; así como un público más amplio, incluyendo el mundo académico, el sector privado y la sociedad civil. Este libro se dirige a todas las personas interesadas en una mayor comprensión de la elaboración de las políticas relacionadas con el nexo entre el agua y las ciudades y cómo las políticas en esta área se han implementado en países que todavía luchan por alcanzar niveles más altos de desempeño económico y social –incluyendo una cobertura total de los servicios en sus ciudades–, buscando, al mismo tiempo, un equilibrio con sus preocupaciones ambientales y climáticas. Si se considera que el 80 por ciento de la población de América Latina vive en áreas urbanas y que, por lo tanto, concentran las demandas municipales e industriales y la presión regional sobre los recursos hídricos de esas áreas, resulta sorprendente que haya tan pocos análisis sistemáticos sobre cómo están vinculados los problemas urbanos asociados al agua desde el nivel de diseño de política a proyectos específicos sobre el terreno, y las brechas significativas de infraestructura y vacíos de gobernabilidad que existen para proporcionar servicios adecuados de agua en la mayoría de las ciudades. Esta es la principal razón por la que el Centro del Agua para América Latina y el Caribe del Tecnológico del Monterrey, en México, asume el liderazgo para llenar esta laguna analítica. La Semana Mundial del Agua celebrada en 2011 estuvo dedicada al Agua en un Mundo Urbanizado y proporcionó el impulso necesario para producir este libro; el Instituto Internacional del Agua de Estocolmo se sumó a la iniciativa y aportó su liderazgo en materia de políticas y una visión global sobre estos temas. En consecuencia, este libro se nutre en gran medida del material original presentado en la Semana Mundial del Agua de 2011. También presenta contribuciones de autores invitados, con un énfasis en el agua y las ciudades, pero sin limitarse a América Latina (hay un capítulo con 2 Agua y Ciudades en América Latina las lecciones importantes de las ciudades de los Estados Unidos en infraestructura verde). Los autores de los diferentes capítulos tienen distintos orígenes profesionales, incluyendo la administración pública, las organizaciones internacionales, el mundo académico y los profesionales del sector. De esta forma, el libro ofrece una rica reflexión sobre el nexo entre el agua y las ciudades desde diversas perspectivas. Descripción del libro “Agua y Ciudades en América Latina” está estructurado en cuatro partes. La primera contiene tres capítulos contextuales que proporcionan el marco general del libro, poniendo énfasis en su importancia conceptual y para las políticas públicas. La segunda parte comprende cinco capítulos centrados en temas clave del agua y el saneamiento, como el acceso universal al agua, la gobernanza del saneamiento y las aguas residuales, el uso del agua subterránea y la política social. La tercera parte tiene cuatro capítulos dedicados a cómo la planeación de la ciudad y el desarrollo urbano pueden afrontar el cambio climático y la mitigación de riesgos de una forma constructiva. La cuarta y última parte examina, en tres capítulos, la importante evolución del crecimiento verde y la infraestructura verde en las ciudades de América Latina, incluyendo reflexiones sobre cómo ciudades de los Estados Unidos han asumido estos conceptos y los han puesto en práctica.