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Los valores de fondo del agua subterránea, BGV (por sus siglas en ingles), de elementos riesgosos, pueden ser integrados como com-ponentes en las políticas de manejo del agua subterránea. Variaciones de los BGV en áreas rurales con actividad agrícola y en áreas urbanas con desarrollo industrial pueden ser referidas a procesos de contaminación del a...
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Context 1
... Guanajuato State, Central Mexico aquifer vulnerability assessments were promoted as additional criterion to prevent and/or to avoid groundwater quality alterations because groundwater is the only source of urban and rural water supply of many cities, like Juventino Rosas and Salamanca, an important industrial centre (SEMARNAT 2013) ( Figure 1). Guanajuato is the only Mexican State with vulnerability assessments, mathematical flow models and monitoring well networks in each regional aquifer (Marañón 2010). Salamanca uses only groundwater for all uses. There is an industrial zone; a refinery, a thermoelectric plant and until 2008 an agrochemical plant that produced DDT generated contaminants (Rodríguez et al ., 2000; Rodríguez et al ., 2001; Rodríguez et al ., 2002). In Salamanca, arsenic, (As), and vanadium, (V), concentrations from natural origin and locally from anthropogenic origin have been reported in the local aquifer system (Rodriguez et al ., 2000; Rodriguez et al ., 2001; Rodriguez et al ., 2015). Vanadium does not represent considerable environmental concern. In the study area groundwater V is originated by infiltrations that carry V contained in particulate emitted by industries using fuel oil number 6 (locally called combustoleo), when the electrostatic precipitators do not work. This fuel has high vanadium contents of 290 to 500 ppm (Salinas et al ., 2001). Late 2004, particulate emissions deposited on soils were analyzed. High V concentrations were detected, 2.09 g/Kg (LAQUIMIA 2004). During combustoleo combustion V is released to the atmosphere as V 2 O 5 in fine ashes suspended in the air. The V content in these emissions varies from 1 to 18 % (WHO 2000). Other authors have measured similar values (Mendoza 1999; Mata, 206; Hernandez et al ., 2007). Particulate is deposited over vulnerable areas and then migrates to the shallow aquifer (Mejía et al ., 2007). In areas In In Salamanca Guanajuato Salamanca, with potential uses State, only the sources Central groundwater intense of Mexico contamination extraction aquifer for all regime and vulnerability uses. crossed There results processes is assessments in an subsidence, industrial of soil zone; and were being groundwater a promoted its refinery, mean contamination, as a thermoelectric additional criterion it is plant necessary to and prevent until to implement and/or 2008 an to planning avoid agrochemical groundwater and management plant quality that alterations tools produced that because allow DDT sustainable groundwater generated contaminants policies is the only of exploitation (Rodríguez source of et urban water al ., resources. and 2000; rural Rodríguez water If there supply et al are ., of 2001; not many surface Rodríguez cities, water like et bodies Juventino al ., 2002). and Rosas agriculture In Salamanca, and Salamanca, and industrial arsenic, an processes important (As), and require industrial vanadium, great centre (V), volumes concentrations (SEMARNAT of water, 2013) from groundwater (Figure 1). natural becomes origin Guanajuato and a valuable locally is the from resource. only anthropogenic Mexican State origin with vulnerability have been reported assessments, in the local mathematical aquifer system flow models (Rodriguez and et monitoring al ., 2000; Rodriguez well networks et al ., in 2001; each Rodriguez regional aquifer et al ., (Marañón 2015). Vanadium 2010). does not represent considerable environmental concern. In the study area groundwater V is originated by infiltrations that carry V contained in particulate emitted by industries using fuel oil number 6 (locally called combustoleo), when the electrostatic precipitators do not work. This fuel has high vanadium contents of 290 to 500 ppm (Salinas et al ., 2001). Late 2004, particulate emissions deposited on soils were analyzed. High V concentrations were detected, 2.09 g/Kg (LAQUIMIA 2004). During combustoleo combustion V is released to the atmosphere as V 2 O 5 in fine ashes suspended in the air. The V content in these emissions varies from 1 to 18 % (WHO 2000). Other authors have measured similar values (Mendoza 1999; Mata, 206; Hernandez et al ., 2007). Particulate is deposited over vulnerable areas and then migrates to the shallow aquifer (Mejía et al ., 2007). In Salamanca, the intense extraction regime results in subsidence, being its mean In Juventino Rosas, an agricultural community with some additional incomes from goat cheese production, high concentrations of arsenic and fluorine has been detected in the regional aquifer (Rodriguez et al ., 2001; Mendoza 1999). Vanadium concentrations are lower than the detection limit. The origin of them is geogenic and related to the geological framework and to the geothermal activity observed in some parts of the aquifer (Morales et al ., 2015). Groundwater temperature varies from 25.5°C to 50°C. The highest temperatures are located near faults and fractures. High temperatures match with the highest groundwater concentrations of As and F concentrations. In hydrothermal systems the solubility of some minerals increases (Eugster, 1986). The main environmental risks associated to arsenic and fluorides are health affectations of the exposed population. The more risky exposition route is water ingestion, even more than ingestion of food with higher As and F concentrations. Arsenic health affectations include skin alterations, cardiovascular problems and cancer in different organs, and for fluoride, dental fluorosis and/or skeletal fluorosis. velocity In The The Juventino main origin 6-7 cm/year environmental of some Rosas, (Rodríguez risky an risks elements et agricultural al associated ., 2002). can The community to be arsenic proposed subsidence and with fluorides through some produces additional are the two health knowledge faults; incomes affectations one from of of them goat of local the cheese crosses and exposed regional the production, urban population. groundwater area high and The concentrations refinery background more lands risky affecting of exposition values, arsenic GBV the route and urban (Reimann fluorine is water infrastructure has ingestion, and been Garret detected (Rodríguez even 2005). more in and the than Concentrations regional Rodríguez, ingestion aquifer of 2006). in food pristine (Rodriguez The with faults areas higher et can can al As facilitate ., define and 2001; F the Mendoza concentrations. the migration natural, 1999). geogenic of surface Vanadium Arsenic levels contaminants. health concentrations of some affectations element are lower include while higher than skin alterations, the concentrations detection cardiovascular limit. could The be problems origin related of them and to anthropogenic cancer is geogenic in different and interventions. related organs, to and the for Anomalous geological fluoride, framework dental concentrations fluorosis and and/or allow to the skeletal the geothermal identification fluorosis. activity of observed potential in contaminant some parts of sources the aquifer and (Morales even et contaminant al ., 2015). migration Groundwater mechanisms. temperature The varies determination from 25.5°C of GBV to in Salamanca 50°C. The can highest help temperatures to define the extension are located of the near zones faults affected and fractures. by anthropogenic High temperatures contamination match sources with like the highest particulate groundwater and/or to know concentrations when an urban of As well and F is concentrations. being contaminated. In hydrothermal In Juventino systems Rosas GBV the solubility can be used of some to define minerals if falls increases are contributing (Eugster, 1986). with ascendant flows rich in elements like arsenic altering the local hydrochemistry, as occurred in Rancho Nuevo, Apaseo El Alto, no far away from J. Rosas where suddenly appears a geothermal manifestation with water rich in arsenic and temperature greater than 65° C. The origin of some risky elements can be proposed through the ...
Context 2
... Guanajuato State, Central Mexico aquifer vulnerability assessments were promoted as additional criterion to prevent and/or to avoid groundwater quality alterations because groundwater is the only source of urban and rural water supply of many cities, like Juventino Rosas and Salamanca, an important industrial centre (SEMARNAT 2013) ( Figure 1). Guanajuato is the only Mexican State with vulnerability assessments, mathematical flow models and monitoring well networks in each regional aquifer (Marañón 2010). Salamanca uses only groundwater for all uses. There is an industrial zone; a refinery, a thermoelectric plant and until 2008 an agrochemical plant that produced DDT generated contaminants (Rodríguez et al ., 2000; Rodríguez et al ., 2001; Rodríguez et al ., 2002). In Salamanca, arsenic, (As), and vanadium, (V), concentrations from natural origin and locally from anthropogenic origin have been reported in the local aquifer system (Rodriguez et al ., 2000; Rodriguez et al ., 2001; Rodriguez et al ., 2015). Vanadium does not represent considerable environmental concern. In the study area groundwater V is originated by infiltrations that carry V contained in particulate emitted by industries using fuel oil number 6 (locally called combustoleo), when the electrostatic precipitators do not work. This fuel has high vanadium contents of 290 to 500 ppm (Salinas et al ., 2001). Late 2004, particulate emissions deposited on soils were analyzed. High V concentrations were detected, 2.09 g/Kg (LAQUIMIA 2004). During combustoleo combustion V is released to the atmosphere as V 2 O 5 in fine ashes suspended in the air. The V content in these emissions varies from 1 to 18 % (WHO 2000). Other authors have measured similar values (Mendoza 1999; Mata, 206; Hernandez et al ., 2007). Particulate is deposited over vulnerable areas and then migrates to the shallow aquifer (Mejía et al ., 2007). In areas In In Salamanca Guanajuato Salamanca, with potential uses State, only the sources Central groundwater intense of Mexico contamination extraction aquifer for all regime and vulnerability uses. crossed There results processes is assessments in an subsidence, industrial of soil zone; and were being groundwater a promoted its refinery, mean contamination, as a thermoelectric additional criterion it is plant necessary to and prevent until to implement and/or 2008 an to planning avoid agrochemical groundwater and management plant quality that alterations tools produced that because allow DDT sustainable groundwater generated contaminants policies is the only of exploitation (Rodríguez source of et urban water al ., resources. and 2000; rural Rodríguez water If there supply et al are ., of 2001; not many surface Rodríguez cities, water like et bodies Juventino al ., 2002). and Rosas agriculture In Salamanca, and Salamanca, and industrial arsenic, an processes important (As), and require industrial vanadium, great centre (V), volumes concentrations (SEMARNAT of water, 2013) from groundwater (Figure 1). natural becomes origin Guanajuato and a valuable locally is the from resource. only anthropogenic Mexican State origin with vulnerability have been reported assessments, in the local mathematical aquifer system flow models (Rodriguez and et monitoring al ., 2000; Rodriguez well networks et al ., in 2001; each Rodriguez regional aquifer et al ., (Marañón 2015). Vanadium 2010). does not represent considerable environmental concern. In the study area groundwater V is originated by infiltrations that carry V contained in particulate emitted by industries using fuel oil number 6 (locally called combustoleo), when the electrostatic precipitators do not work. This fuel has high vanadium contents of 290 to 500 ppm (Salinas et al ., 2001). Late 2004, particulate emissions deposited on soils were analyzed. High V concentrations were detected, 2.09 g/Kg (LAQUIMIA 2004). During combustoleo combustion V is released to the atmosphere as V 2 O 5 in fine ashes suspended in the air. The V content in these emissions varies from 1 to 18 % (WHO 2000). Other authors have measured similar values (Mendoza 1999; Mata, 206; Hernandez et al ., 2007). Particulate is deposited over vulnerable areas and then migrates to the shallow aquifer (Mejía et al ., 2007). In Salamanca, the intense extraction regime results in subsidence, being its mean In Juventino Rosas, an agricultural community with some additional incomes from goat cheese production, high concentrations of arsenic and fluorine has been detected in the regional aquifer (Rodriguez et al ., 2001; Mendoza 1999). Vanadium concentrations are lower than the detection limit. The origin of them is geogenic and related to the geological framework and to the geothermal activity observed in some parts of the aquifer (Morales et al ., 2015). Groundwater temperature varies from 25.5°C to 50°C. The highest temperatures are located near faults and fractures. High temperatures match with the highest groundwater concentrations of As and F concentrations. In hydrothermal systems the solubility of some minerals increases (Eugster, 1986). The main environmental risks associated to arsenic and fluorides are health affectations of the exposed population. The more risky exposition route is water ingestion, even more than ingestion of food with higher As and ...
Context 3
... geological Data distribution risky element are collected composition from can to the be elements or higher chosen selected of than the data related the from aquifer set maximum (Kunkel directly reliable and or the historical et concentrations al., indirectly factors 2006). archives that to recommended When an control (Runnells anthropogenic the number local for et potable and al., of influence. regional data 1992). water is Then hydrodynamic. There great, or other GBV hundreds are specific can several be GBV of use. also data, methodological cannot divided This regression be situation assigned in natural or proposals clusters occurs to and all no-natural. the for analysis with GBV aquifer arsenic calculation. can system GBV concentrations be useful unless are Before to representatives the get data reported aquifer representative management presents in some only of homogeneity is GBV aquifers carried a (Vyas region (Hernández-García out, et and in al., the its cannot 2001). geological appraisals be attributed composition of and outliers Custodio, to with and any recognized a Dixon’s 2004; similar Armienta Q hydrodynamic test natural rule et source al., out 1997). behavior values of contamination When that in its the do entire GBV not in other domain. correspond can be areas considered (NREPC, with the natural, 2004). rest of it can group be values. taken like In this pristine case concentrations it was observed in areas that the where calculated some values elements not can exceed be originated the values from anthropogenic of tables and that sources. data was rejected. The Environmental Protection Agency from US uses the Grubb Test to choose the concentration values to get a representative mean value (USEPA, 1988). Breckenridge and Crockett (1995) have used variation coefficient values (relationship between standard deviation and mean value) smaller than 0.5 to define the data set to be used. The GBV are not necessarily related to standards for any water use. The GBV for a risky element can be higher than the maximum concentrations recommended for potable water or other specific use. This situation occurs with arsenic concentrations reported in some aquifers (Hernández-García and Custodio, 2004; Armienta et al., 1997). When the GBV can be considered natural, it can be taken like pristine concentrations in areas where some elements can be originated from anthropogenic sources. In Salamanca all the chemical analyzes were reviewed to choose only data obtained with the same analytical methodology. A data set was compiled and used for GBV determination. The In The Salamanca area Water was Framework all divided the chemical in Northern, Directive analyzes Central of were the European reviewed and Southern to Union choose Zone. considers only The data that Lerma obtained in the River definition with that the of same crosses GBV analytical must the urban be methodology. included area is acting not only A as data the a hydraulic set aquifer was characteristics compiled barrier and and a used natural but for also GBV frontier. the determination. characteristics The division of took the also solute in and consideration water receptor the bodies geological too (Muller composition et al., of 2006). the aquifer (to the North prevail sedimentary units of variable granulometry like sand, gravels and clay, whereas to the south volcanic rocks; basaltic flows, fractured basalts and volcanic ashes). A shallow aquifer unit is located in the Central zone. The Northern The area was divided in Northern, Central and Southern Zone. The Lerma River that crosses the urban area is acting as a hydraulic barrier and a natural frontier. The division took also in consideration the geological composition of the aquifer (to the North prevail sedimentary units of variable granulometry like sand, gravels and clay, whereas to the south volcanic rocks; basaltic flows, fractured basalts and volcanic ashes). A shallow aquifer unit is located in the Central zone. The Northern In JR the area was divided in three zones; NW zone with volcanic basaltic and ignimbrite- rhyolitic rocks: NE zone with volcanic ignimbrite- rhyolitic and sedimentary rocks and Southern, S, zone in the sedimentary plain. The division took in consideration the geological composition of the aquifer (to the North volcanic rocks; basaltic and ignimbrite-rhyolitcs flows, fractured volcanic rocks and ashes, whereas to the South prevail sedimentary units of variable granulometry like sand, gravels and clay the mainly igneous origin, interbeded with volcanic material as rhyolite and basalt). The Northern zones are relatively pristine areas. A shallow aquifer unit is located in the South zone. It is not excluded the influence of the agricultural activity. zone In The is JR well a the relatively Dulces area was Nombres, pristine divided area, DN, in three without was zones; put the in influence NW the NW zone zone, with of the whereas volcanic industrial basaltic the area wells (Figure 1). and Val ignimbrite- 1 and Val rhyolitic rocks: NE zone with volcanic ignimbrite- rhyolitic and sedimentary rocks and Southern, S, zone in the sedimentary plain. The division took in consideration the geological composition of the aquifer (to the North volcanic rocks; basaltic and ignimbrite-rhyolitcs flows, fractured volcanic rocks and ashes, whereas to the South prevail sedimentary units of variable granulometry like sand, gravels and clay the mainly igneous origin, interbeded with volcanic material as rhyolite and basalt). The Northern zones are relatively pristine areas. A shallow aquifer unit is located in the South zone. It is not excluded the influence of the agricultural activity. The well Dulces Nombres, DN, was put in the NW zone, whereas the wells Val 1 and Val Notwithstanding the Wells 9, 10 and 13 are located in the plain there are hydrochemical differences between them due to geological heterogeneities. The well 10, in the S zone, is intensely exploited for urban supply. It is one of the hottest wells that could be an indicator of a fault not mapped. The wells 9 and 13 were put in the NW zone because their hydrogeochemical behavior indicate that part of the well is extracting water from some rhyolitic unit. 2 in Notwithstanding The the zone data S, set although from the Wells Salamanca they 9, are 10 very and is close formed 13 are to each located by 51 other. files in the of The 25 plain well wells. DN there was Average are drilled hydrochemical and in standard rhyolites (Tom) differences deviation, and the SD, between wells were Val them obtained 1 and due Val for to 2 each in geological volcanic well. sediments. heterogeneities. The data set The from The faults Juventino well could 10, Rosas be in the working is S formed zone, as natural is intensely hydraulic exploited conducts for whereby urban supply. hot water It with is one other of the composition hottest wells that that infiltrated could be water an can indicator circulate. of a The fault hot not water mapped. can The alter wells the natural 9 and 13 composition were put of in the the aquifer NW zone water. because their hydrogeochemical behavior indicate that part of the well is extracting water from some rhyolitic unit. The data set from Salamanca is formed by 51 files of 25 wells. Average and standard deviation, SD, were obtained for each well. The data set from Juventino Rosas is formed by 91 data files of 23 wells. Well distribution for Salamanca is showed in figure 2: The Northern Zone is represented by 6 wells; the central zone has 8 and the southern zone comprises 11. Well distribution for Juventino Rosas is showed in figure 3: The NW Zone is represented by 9 wells; the NE zone has 4 and the South zone comprises 10. Some of the detected concentrations are greater than the Mexican standards for drinking water (Fig 4). In the S zone of Salamanca, all wells have far exceeded the national standard for drinking water (Figure 2). The highest concentration was 0.076 mg/L in the well P 21. In the N zone, the As values were greater than the national standard, with a maximum in the well P 30, 0.777 mg/L. The wells of the central zone, (C), also had concentrations over the standard with a maximum of 0.068 mg/L in the well P 2. The maximum value of vanadium in the S zone was 0.091 mg/L in the well P22. For the N zone the greater concentration of V The NE zone of Juventino Rosas of the wells exceeded the national standards for As and F. In the NW zone the wells JR 05 and JR 08 had concentrations over the As standard. The maximum value was found in the well JR 05, 0.036 mg/L. In the S zone, the wells Rom, Tej, Val 1 and JR 10 had values over the standard with a maximum in the wells Pozos and JR 10, 0.046 mg/L. The wells Tej, Val 2, Rom, Pozos, JR 10 and SJ Mer exceeded the standard for F; the highest value was 2.95 mg/L in the well Tej. was The Three detected NE set zone of in of mean the Juventino well values P30, Rosas with 0.062 its of mg/L. the SD wells were In the exceeded calculated. central the area, The national Grubb the well Test, standards P 10 (Z), had was for the As highest applied and V F. to concentration, In each the data NW set. zone 0.065 If the Z is mg/L. wells greater JR than 05 and the JR table 08 had values concentrations for N data, the over respective the As well standard. is excluded The maximum of the data value set because was found the concentration in the well JR does 05, 0.036 not correspond mg/L. In the to a S zone, normal the distribution. wells Rom, The Tej, Val Grubb 1 and Test JR considers 10 had the values mean, over the the SD standard and the with concentration a maximum value in the for wells each Pozos well (NREPC, and JR 10, op 0.046 cit). mg/L. The wells Tej, Val 2, Rom, Pozos, JR 10 and SJ Mer exceeded the standard for F; the highest value was 2.95 mg/L in the well Tej. Three set of mean values with its SD were calculated. The Grubb Test, (Z), was applied to each data set. If Z is ...
Context 4
... Guanajuato State, Central Mexico aquifer vulnerability assessments were promoted as additional criterion to prevent and/or to avoid groundwater quality alterations because groundwater is the only source of urban and rural water supply of many cities, like Juventino Rosas and Salamanca, an important industrial centre (SEMARNAT 2013) ( Figure 1). Guanajuato is the only Mexican State with vulnerability assessments, mathematical flow models and monitoring well networks in each regional aquifer (Marañón 2010). ...
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... Considering that water that is pumped at greater depths is mineralized mostly because of the residence time and interaction with geological materials, it is essential to characterize groundwater to detect hydrogeochemical processes, changes in its chemical composition, and the mixing of different groundwater sources via local or regional flows [9,10]. Arsenic and fluoride have been reported in some areas of Bajío Guanajuatense [11][12][13]. The origin, relationship to geological features, or hydraulic connections between aquifers have only been explored in a few rare instances despite reports of high amounts of arsenic in groundwater used by more than 1.5 million people [14]. ...
This study investigates the natural hydrogeochemical mechanisms that govern groundwater chemistry at the margins of the Silao-Romita, Valle de León, and La Muralla aquifers in Mexico's "Bajío Guanajuatense". The wells of the La Muralla aquifer have temperatures ranging from 25 to 45 • C, while in the valleys, the temperatures range from 25 to 29 • C. In the Sierra de Guanajuato recharge zone, the thermal spring registers 95 • C. High Na concentrations (125 to 178 mg/L) are measured due to thermalism. One sample includes 316 mg/L of SO 4 , which is related to a potential gypsum zone. Three hydrogeochemical facies are identified (Ca-Mg HCO 3 , Na-Ca-HCO 3 , and Na-HCO 3). The hydrogeochemical characterization and processes imply hydraulic linkage via regional thermal flows enhanced by faults and the mixing of local flow waters with intermediate flows. The isotopic results indicate that part of the groundwater volume has been exposed to local evaporation processes due to the presence of surface water bodies and irrigation returns. The highest isotopic enrichment is observed near or in the recharge regions. In contrast, the most depleted zones are in the valleys, where there is a more significant interaction with the rock and a longer residence time, implying a mixture of local water flows with deeper or intermediate flows, which, when combined with water geochemistry, indicates a connection between the aquifers studied. The Kruskal-Wallis variance tests, used to compare the differences between aquifers, show that the Valle de León aquifer has more significant differences with respect to the Silao-Romita and La Muralla aquifers. This study's findings are essential for one of central Mexico's most populous and economically active areas.
... These "graben siliciclastic shallow aquifers" are generally described as multilayered and compartmented aquifers (Arango-Galván et al. 2011;Billarent-Cedillo et al. 2021;Carrera-Hernández et al. 2016;Guerrero-Martínez et al. 2018;Sanchez et al. 2018 among others). Moreover, groundwater overexploitation in volcanic aquifers seems related to local thermal anomalies and increase in natural As, F, Cr, Cs concentrations (Morales et al. 2015;Rodríguez et al. 2016). Despite the fact that groundwater is the main water source available for public use in Mexico, to date there is a lack of knowledge regarding the interaction of meteoric water with groundwater and of the understanding of regional and local groundwater flows, leading to simplistic estimations of aquifer recharge (Cruz-Ayala and Megdal 2020). ...
Water supply in semiarid areas in Mexico depends on water extraction from compartmentalized aquifers where large drawdown rates can be observed due to increasing demand from urban, industrial and agricultural users. Understanding the behavior of these aquifers is a necessity in order to improve the estimation of water balances. Accordingly, this study assembles both geochemical and isotopic data to identify the source of recharge to the San Juan del Río graben aquifer and to determine its dynamics. The geological model developed with the aforementioned data reveals a complex system composed of a heterogeneous multilayered compartmentalized aquifer. The San Juan del Rio basin is composed of (1) the Amealco perched aquifer, (2) a shallow granular aquifer, and (3) a fractured aquifer. Hydrogeochemical and isotopic data (δ2H, δ18O, δ13C and correct carbon activity (Δ14C)) allow for identification of three end-member sources: (1) local meteoric recharge, (2) old groundwater contained in the siliciclastic shallow aquifer, and (3) regional/local hydrothermal recharge. The contribution of both meteoric and regional hydrogeothermal flow to the different aquifer compartments is determined through a principal component analysis of the hydrogeochemical data. With the aforementioned analysis it was found that the dominant contribution source for all aquifer compartments is meteoric water (up to 60% with a median of 50%), while the regional hydrothermal groundwater contribution represents 15%, even for the shallow aquifer.
... Arsenic (As) pollution in the State of Guanajuato has gained more attention in the last years. Several studies performed in the region indicated high contents of As in groundwaters used for irrigation, which are above the accepted world standard limits, with a mean of 0.33 mg L −1 (Rodríguez et al. 2016), an accumulation in soils with a range of 1.0-14.0 mg/kg (López-Pérez et al. 2017;Zanor et al. 2019) and in crops with a mean of 14.1 mg kg −1 in barley (Saldaña-Robles et al. 2018), as As can accumulate in soil and be transferred into the food chain (Lu et al. 2010). ...
In this report, physical and chemical properties, and total arsenic (As) concentrations were analyzed in agricultural (MASE) and mining soils (SMI) in the State of Guanajuato, México. Additionally, a metagenomic analysis of both types of soils was the bases for the identification and selection of bacteria and fungi resistant to As. The SMI soil showed higher concentration of As (39 mg kg-1) as compared to MASE soil (15 mg kg-1). The metagenome showed a total of 175,240 reads from both soils. MASE soil showed higher diversity of bacteria, while the SMI soil showed higher diversity of fungi. 16S rRNA analysis showed that the phylum Proteobacteria showed the highest proportion (39.6% in MASE and 36.4% in SMI) and Acidobacteria was the second most representative (24.2% in SMI and 11.6% in MASE). 18S rRNA analysis, showed that the phylum Glomeromycota was found only in the SMI soils (11.6%), while Ascomycota was the most abundant, followed by Basidiomycota, and Zygomycota, in both soils. Genera Bacillus and Penicillium were able to grow in As concentrations as high as 5 and 10 mM, reduced As (V) to As (III), and removed As at 9.8% and 12.1% rates, respectively. When aoxB, arsB, ACR3(1), ACR3(2,) and arrA genes were explored, only the arsB gene was identified in Bacillus sp., B. simplex, and B. megaterium. In general, SMI soils showed more microorganisms resistant to As than MASE soils. Bacteria and fungi selected in this work may show potential to be used as bioremediation agents in As contaminated soils.
... The investigated area is located in the State of Guanajuato, Mexico, which is recognized worldwide for its industrial, mining, and agricultural activities, where the use of groundwater is of paramount importance (CEAG, 2000). Severe problems associated with water quality and availability have been reported in all the aquifers in this area (Rodríguez et al., 2016). In the townships of Villagran and Juventino Rosas, groundwater is abstracted from two different aquifers. ...
... Currently, wells must be drilled at greater depths to extract the groundwater. Furthermore, recent studies have reported that the deep aquifer has low-temperature geothermal characteristics, with a high content of As and F - Rodríguez et al., 2016). Due to over-exploitation, it has been reported that faults act as preferential conduits for the migration of deep geothermal fluids . ...
... These rhyolites and ignimbrites are overlaid by Middle Miocene extensional-related basaltic and andesitic rocks (Alaniz-Álvarez et al., 2001). The basement is composed of sedimentary rocks with low-grade metamorphism, with a transmissivity of 1.2×10 -4 m 2 /s (Rodríguez et al., 2016). Figure 1. ...
This study was conducted to identify the origin, hydrogeochemical processes and evolution of groundwater in a tectonic valley. This study was carried out with the aim of quantifying the proportions of groundwater flows contributing to the water chemistry abstracted in a zone of convergence favored by the presence of active faults. The study area is located in the Trans-Mexican Volcanic Belt. End members methodology was applied to identify the mixing of hydrothermal with fresh groundwater, where changes in the aquifer geology result in distinct groundwater chemical signatures. Ternary mixing was quantified using conservative elements. Moreover, other evolutionary processes, such as ion exchange and silicate weathering occur due to changes in the geology of the area. In ternary mixing, each of the end members is associated with the lithology through which it circulates. The local flow contributes 70% of the water to the system, the intermediate flow contributes 14%, and the regional flow contributes 16%. Three types of water are produced: Na-HCO3, due to the interaction of water with volcanic rocks of rhyolitic composition, Na-Mg-HCO3, due to the interaction of water with volcanic rocks of basaltic-andesite composition, and Ca-HCO3, due to the interaction of water with sedimentary calcareous rocks.
... En la porción Oeste del ACV (con una superficie total de 554.04 km 2 ), lugar ubicado en la región Sureste del BG, conformado por los municipios de Villagrán (Vill) y Santa Cruz de Juventino Rosas (JR), existen más de 1,100 pozos que extraen agua subterránea principalmente para la agricultura como se hace mención previamente (Foster et al., 2004;IEEG, 2008;Rodríguez et al., 2016). Los grupos poblacionales más numerosos están concentrados en sus cabeceras municipales. ...
... La topografía comprende al Norte la parte Sudeste de la Sierra de Guanajuato, al Centro la cuenca está rellenada por sedimentos aluviales-lacustres y al Sur por volcanes monogenéticos pertenecientes a la Faja Volcánica Transmexicana (FVTM) (Rodríguez et al., 2016). El suelo en la región es de tipo Vertisol en su mayoría y en segundo término Phaeozem, conformando aproximadamente un 70%, del total, aunque existen 15 tipos de suelo distintos (INEGI, 2016). ...
... Además, en toda la zona de estudio existen fallas tectónicas profundas y fallas generadas por subsidencia, con direcciones preferenciales NE-SW, NW-SE, N-S, y E-W. Estas estructuras, bajo ciertas circunstancias, actúan como zonas impermeables debido a que están rellenas de material arcilloso o pueden funcionar como canales de migración de contaminantes (al acuífero somero principalmente), producto de las actividades humanas Rodríguez y Schroeder, 2010;Rodríguez et al., 2016). (Fig. 4), pero al realizar una evaluación con respecto al tipo de agua se observa que el contenido de HCO3 -, SO4 2y Clversus NO3varía entre los tipos de agua WT4, WT 5, y WT 6 ( Fig. 4a, b y c), y también es evidente que en el año 2017 el tipo de agua WT 5 presenta los valores más elevados de todos los aniones. ...
The sub-province Bajío Guanajuatense is located in Central Mexico, is one of the most important agricultural areas in Mexico, where are used large volumes of water. The current panorama of Guanajuato shows an increase of more than three times in the use of groundwater, compared to extraction 30 years ago; this water is used to maximize crop yields; another problem that has increased is the excessive use of nitrogen fertilizers in all the area. This context becomes more serious considering that in the study area, occurs problems of overexploitation, depletion of the piezometric level, presence of deep faults and fractures, coupled with contamination at different levels of the aquifer by nitrogen compounds. The objective of this work is to evaluate the presence of nitrogen compounds at different depths of the aquifer, in addition, to identifying isotopic and hydrogeochemical sources, their transformations and the processes related to the high NO3- content in groundwater. Based on the results obtained from the concentration of NO3-, major, minor chemical elements, trace and isotopes, two sources of pollution have been identified; one related to agriculture and the second to wastewater treatment, This has caused that NO3 content exceed the values allowed by NOM-127, according to the sampling data of 2017 and 2019, not only the shallow aquifer is polluted, also the deep. Two groundwater sampling campaigns were carried out in 32 urban and agricultural wells of the municipalities of Vill and JR in Guanajuato, in rainy and dry season, following national and international methods. Major, minor and some trace elements were determined, as well as stable isotopes. The origin of the high content of NO3- is anthropogenic; the highest values were quantified during the dry season. Nitrates migrate more easily through faults and deep fractures, mainly in the central south zone of the study area to the middle aquifer and possibly to the deep one, this process is relevant since the area is recognized as an impermeable medium due to the presence of large layers of clays. A wastewater treatment plant is a source of contamination, the application of fertilizers would be the other possible source of contamination. The transformation of nitrogen compounds could affect the isotopic behavior of δ18O, although it is not ruled out that it could be due to evaporation processes and infiltration of shallow water. This information should be considered since the presence of nitrates in the environment represents a risk to the health of the population that is supplied by the same aquifer system where these activities take place.
... The groundwater that migrates to the basin center feeds the exploited aquifer. Local fractured rhyolites and ignimbritic unconsolidated tuffs show a medium-to high-variable permeability; in some places, rhyolitic rocks act as the basement (Rodríguez et al. 2016). Basaltic and andesitic rocks have a high permeability controlled by fractures and vesicles; these rocks are excellent media for the recharge of the aquifer, mainly in the southern section, where the groundwater is hosted in the intercalation of volcanic rocks with lacustrine-alluvial sediments (GUYSA 1998; Morales-Arredondo et al. 2018b). ...
... Different hydrogeochemical processes that are involved in the acquisition of these characteristics have been identified, such as silicate weathering and ion exchange (Morales-Arredondo et al. 2016a). The groundwater flow crosses through felsic volcanic material Rodríguez et al. 2015;2016) (Fig. 2d). ...
A hydrogeochemical and isotopic study was conducted in the western portion of the Celaya Valley Aquifer, Mexico, to assess the role of dissolved carbon dioxide in groundwater contamination. The partial pressure of carbon dioxide value is used to evaluate a complex hydrogeochemical environment, and the carbon dioxide behavior is used to identify the natural and anthropogenic processes related to pollution sources in a thermal aquifer located in the western portion of the Celaya Valley Aquifer. Results indicate that during groundwater migration from the recharge zone to the center of the basin, a hydrogeochemical evolution from calcium bicarbonated and calcium–bicarbonate–chloride type to sodium–bicarbonate type occurs. During this process, deep fluids that migrate through the fault system interact with the aquifer; these fluids contain carbon dioxide released from the metamorphism of the carbonated basement, although another source is not discarded as the dissolved inorganic carbon typical of meteoric groundwater produced from atmospheric carbon dioxide. The hydrogeochemical and isotopic evidences of delta carbon thirteen, delta oxygen eighteen and delta deuterium indicate that the dissolved content of carbon dioxide in the aquifer is involved in the silicate weathering process that plays a major role during water type evolution. In some cases, during weathering, potentially toxic elements are released in amounts that represent an environmental risk, among which arsenic and fluoride stand out, mainly in depth wells. Additionally, other isotopic and hydrogeochemical evidence indicates a biological source of carbon dioxide in the shallow aquifer, primarily due to the agricultural activity carried out in the entire study area.
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... A recent study by López- Pérez et al. (2017) reported total As concentrations in surface soils of the Guanajuato state, ranging from 0.01 to 14.90 mg/kg. Although these soils are usually irrigated with groundwater with mean As concentration of 0.33 mg/L ( Rodríguez et al. 2016), the impact of this practice on the As levels of the irrigated soils has not been assessed so far. ...
... This study considers pH and As concentration ranges, which are similar to real conditions found in water used for irrigation in the region of Guanajuato, Mexico. Whereas, drinking water of the region presented As concentration ranges from 0.01 to 0.03 mg·dm -3 , groundwater used for irrigation in Irapuato, Guanajuato, presented an As concentration of 0.33 mg·dm -3 [30]. Thus, the adsorption capacity of arsenic(V) onto GEH found in the present work may be considered as a well approximation to the actual working conditions in Guanajuato. ...
The present study discusses the adsorption kinetics of arsenic(V) on granular ferric hydroxide (GEH) and the GEH adsorption capacity for arsenic(V) at equilibrium. The impact of temperature on GEH adsorption capacity was studied, as well as the effects of
the initial concentration of arsenic(V) and GEH concentration on the adsorption rates of arsenic(V). The Freundlich isotherm describes the arsenic(V) adsorption behavior reasonably well (r2 > 0.965). The adsorption kinetics was studied by fitting the experimental data to both first-order and second-order models. The maximum adsorption
capacity of arsenic(V) on GEH was 2.701 mg·g–1, which is higher than the adsorption capacities of other adsorbents reported. The kinetics of arsenic(V) adsorption was well defined by the second-order model, with the correlation coefficients in the range of 0.960–0.987. This study shows that due to its properties, GEH is a good candida
te for removal of arsenic(V) from groundwater.
... Thus, the area is prone to drought and its main water supply for commercial and domestic use is from an aquifer. However, due to poor management, El Bajío suffers from overexploitation of its aquifers (see Table 2) and contamination of its water resources to various degrees; because of this overexploitation, water has to be obtained from ever deeper wells and this water often contains elements such as arsenic, vanadium and fluorine, amongst others, which reduces its quality Rodríguez et al., 2015). ...
The arrival of new industries in some municipalities of ‘El Bajío’ in Guanajuato state, Mexico, has brought about appreciable economic development and human impacts, but has also caused changes in the management of the aquifers from which they get water for their operations. In some cases, the aquifers are overexploited and contaminated at different levels. A number of agencies have the main responsibility for managing, protecting and conducting studies on water use in both municipalities and the state and, in this context, experts from these agencies were consulted as part of this study about what environmental, social, economic and hydrological aspects had the highest priority when considering the establishment of a new industry in the zone. The analytical hierarchy process (AHP) methodology was used. Results show that hydrological aspects were the most important and, within them, treatment and reuse of water had the highest priority. It was concluded, therefore, that for the experts to reuse water in some activities and productive processes must be an option to decrease the water extraction from aquifers, supposing that the treatment process complied with the required regulations. Given the present conditions in the region, we can affirm that these results are applicable to the whole of El Bajío.
... Morales-Arredondo et al. (2015) señalaron un origen geogénico del As en el agua subterránea, asociado especialmente a rocas riolíticas y a la influencia de la actividad geotermal en el municipio de Juventino Rosas, en el centro del estado de Guanajuato. Rodríguez et al. (2016) cuantificaron 330 mg As L -1 en agua de pozo para riego en la localidad de El Copal, comunidad de Irapuato, Guanajuato. ...
... Morales-Arredondo et al. (2015) indicated a geogenic origin of As in the groundwater, associated especially with rhyolitic rocks and the influence of geothermal activity in the municipality of Juventino Rosas, in the center of Guanajuato. Rodríguez et al. (2016) quantified 330 mg As L -1 in well water for irrigation in the town of El Copal, community of Irapuato, Guanajuato. ...
Irrigation with water contaminated with arsenic (As) is a risk to human health since it causes the accumulation of this element in the soil and affects crop yield. The objective of this study was to evaluate the effect of phosphorus (P) concentration on irrigation water contaminated with As and its accumulation in the cultivation of barley (Hordeum vulgare L.). The hypothesis was that the accumulation of As by the barley plant is inverse to the concentration of P in the irrigation water. The effect of P was evaluated with a multifactorial experimental design, with a variable level of type 32. Forty-five seeds were planted in soil piles of 0.126 m2, with 20.16 L of irrigation with aqueous solutions of As (50, 200 and 400 μg L-1) and P (120, 210 and 300 μg L-1). We determined the content of As in the soil at the beginning and end of the study, and in the plant at 45 and 90 d after sowing. The analysis of the elements was carried out by ICP-AES after the digestion of the materials with microwaves. The average accumulation of As in the plant (14 101 ± 1 813 μg kg-1) with the treatment of 400 μg L-1 of As was 2.4 times higher than in the treatment with 50 μg L-1. In the treatment with higher concentration of P (300 μg L-1) the plant accumulated an average of 6 871 ± 1 051 μg kg-1, that is, 41.4 % less As than the treatment with 120 μg L-1. The concentrations of P and As in the irrigation water had a significant effect (p(0.05) in the accumulation of as in the barley plant; in addition, P inhibits the absorption of As in barley.
