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Article

Upward Trends and Lithological and Climatic Controls of Groundwater Arsenic, Fluoride, and Nitrate in Central Mexico

by
Heriberto Morales-deAvila
1,
Mélida Gutiérrez
2,*,
Claudia Patricia Colmenero-Chacón
2,
Hugo Enrique Júnez-Ferreira
1 and
Maria Vicenta Esteller-Alberich
3
1
Unidad Académica de Ingeniería Eléctrica, Universidad Autónoma de Zacatecas “Francisco García Salinas”, Zacatecas 98160, Mexico
2
Department of Geography, Geology and Planning, Missouri State University, Springfield, MO 65897, USA
3
Inter-American Institute of Technology and Water Sciences, Autonomous University of the State of Mexico, Toluca 50120, Mexico
*
Author to whom correspondence should be addressed.
Minerals 2023, 13(9), 1145; https://doi.org/10.3390/min13091145
Submission received: 25 June 2023 / Revised: 23 August 2023 / Accepted: 29 August 2023 / Published: 30 August 2023
(This article belongs to the Section Environmental Mineralogy and Biogeochemistry)
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Versions Notes

Abstract

:
Central Mexico is known for its high concentrations of geogenic arsenic (As) and fluoride (F−) in the groundwater; however, concentrations vary widely within the region. To identify specific hydrogeological processes that cause these variations, the study area was divided into four sections, each section with a particular lithology, climate, and land use. Nitrate was added to the analysis as a common anthropic contaminant in this area as one that is indicative of human and agricultural activities. Concentration maps, Na-normalized diagrams, Spearman correlation, and upward trend analyses were applied to 77 wells distributed across the four sections. Specific patterns of concentration emerged according to climate and the lithology of the exposed rocks. A sharp reduction of F− concentrations in the section where carbonate rocks outcrop suggested co-precipitation of F− with calcite. The Mann–Kendall method detected upward trends in 5 out of 54 wells for As and NO3–N and three for F− at a 95% probability level. Several wells with upward trends of As and NO3–N overlapped. Only one well showed a downward trend for NO3–N. The results show the degree to which lithology and climate affect groundwater quality, information that leads to a better understanding of the processes (and health hazards) that govern As, F−, and NO3–N concentrations, which could be construed to include the potential effect of human activities such as overfertilization and altering groundwater residence time via groundwater withdrawals.

1. Introduction

Geogenic arsenic (As) in groundwater exceeds drinking water guidelines in many world regions [1,2,3]. Its presence is a concern due to its toxicity to humans at low concentrations and the development of serious illnesses when chronically ingested. Drinking water limits vary from country to country, but a commonly used value, e.g., World Health Organization (WHO), United States, and Mexico, is 0.010 mg L−1. The latter is transitioning to 0.01 mg L−1 from its previous limit of 0.025 mg L−1. Unfortunately, regions containing geogenic As also report the co-occurrence of other potentially toxic ions, including fluoride (F−), uranium (U), radium (Ra), and molybdenum (Mo) [4,5,6,7]. Among these, the presence of geogenic F− is more prevalent and found at high concentrations, often surpassing the existing drinking water limit of 1.0 mg/L (or 1.5 mg L−1 F−, depending on the country) [2,8,9,10], whereas the other ions are present at mostly trace concentrations. The source (primary minerals) of both As and F has been reported to be the weathering of volcanic rocks (e.g., rhyolite, tuff, andesite), a process intensified by high temperature (hydrothermal waters) [3,4,8,9,10]. The risk to human health by the occurrence of As or F− is well documented [9,10]. However, the health risk of having both contaminants present continues to be investigated [9,11,12,13,14].
Another groundwater contaminant of global concern is nitrate (NO3), an anthropic, soluble compound whose concentration is increasing in many aquifers worldwide [15,16]. The public health guidelines recommend NO3–N not to exceed 10 mg L−1 [16,17]. The guideline values are expressed as either NO3 or NO3–N; therefore, the 50 mg NO3 L−1 limit of WHO roughly corresponds to the US EPA’s guideline of 10 mg NO3–N L−1. The limit of 11 mg NO3–N L−1 has been established in Mexico [18] (NOM 2021). Under oxidizing conditions, NO3 leaches from the surface after fertilizers and manure are applied to the land and also by leakage of treated and non-treated sewage, e.g., septic tanks [19]. Because of its relation to sewage and agriculture, NO3 is used as an indicator of a variety of contaminants, including pharmaceuticals, personal care products, and pesticides [20].
The hydrogeochemical processes governing each of As, F−, and NO3 in groundwater have been the subject of multiple studies. These studies focus on their potential source, concentration distribution, health risk, enriching processes, treatment methods, or a combination of these factors [21,22,23,24]. The oxidizing or reducing condition of an aquifer is one of the most important parameters since it leads to different chemical forms of the solute; for example, As as arsenate or arsenite, N as nitrate, nitrite, or ammonia, F− as a free ion or a complex ion, which in turn affect their toxicity, affinity to adsorb, and reaction to other ions [3,6,21,25].
The largest concentrations of As and F− in Mexico occur in the semiarid north-central areas, up to 46.3 µg L−1 As and 45.2 mg L−1 F− [23]. The chemical forms of As are reported as As (V) and F− (free ion), and these co-occur [10,11,12,13,14,25]. Concentration maps of As and F− have shown a scattered distribution, with wells of high concentration next to wells of low concentration. The values and distribution pattern have been commonly related to not only the mineral composition of the aquifer but also to the alkalinity and hydrothermal conditions. Studies are now encompassing hydrogeochemical enriching processes, among them evaporation, residence time, presence of other ions, and mixing with contaminated flows from mining or agricultural activities [10,26,27,28]. In Zacatecas (Central Mexico), groundwater is the primary source of water for drinking, agricultural, and industrial purposes. Large groundwater withdrawals have caused aquifers surrounding the capital city of Zacatecas to be severely depleted [29]. A tool needed to address the abovementioned water quality and water supply problems would be a state-wide analysis of the processes governing groundwater quality to develop strategies that would increase the sustainability of the resource. These strategies are best if supported by models that accurately include expected changes in land use and climate. To this purpose, we analyzed available water quality data for As, F−, and nitrate (NO3–N) in a regional-scale study and related their concentrations to the processes likely responsible for the observed spatial and temporal variations, such as weathering, evaporation, and co-precipitation.
The objectives of this study were to (1) determine the extent and variation of As, F−, and NO3–N concentrations within the state of Zacatecas using publicly available water data, (2) delineate the main processes that affect the concentrations of As, F−, and NO3–N, (3) determine the variation with respect to time for each of these solutes using well records with 10 years or longer data, and (4) comment on how the information above can be used to add sustainability to the management of the resource.

2. Materials and Methods

2.1. Description of Study Area

The state of Zacatecas (Figure 1) and neighboring areas have been identified as a region whose groundwater contains high concentrations of As and F− [10,11,12,13,14,23,30]. The capital city of the state, Zacatecas, together with the adjacent city of Guadalupe, has a population of 600,000 and contains half of the population of the state. Mining of gold, silver, and lead has been a historically important economic activity in this region, and although mine wastes may contribute As and F− to the local groundwater [28,30], they generally concentrate on the surface and near the waste disposal site, for which natural sources outperform mining wastes as a source of As and F− on a regional scale [4,10,22]. The presence of As and F− has been related to a large extent to the weathering of volcanic rock fragments comprising alluvial fill or to the enrichment by mineralized water upwelling from underlying fractured rocks [5,7,29,30,31].

2.2. Geology

The Mesa Central is an elevated plateau in central Mexico bound to the west by the Sierra Madre Occidental, to the east by the Sierra Madre Oriental, and to the south by the Mexican Volcanic Belt (Figure 1). This region was profoundly affected by two major geologic events: one was the emplacement of a large volume of felsic volcanic rocks during the formation of the Sierra Madre Occidental and the Laramide Orogeny, both events occurring in various episodes ranging in time from late Mesozoic to the Tertiary (Paleogene and Neogene periods). These events produced a profusion of normal faulting due to crustal extension, which was at times synchronous with volcanism [32,33]. The Mesa Central has been divided into north and south sections based on outcrop lithology and geomorphic features [33]. In the northern part, the volcanic cover is nearly completely eroded, allowing pre-Tertiary sedimentary rocks to be exposed, whereas the southern part is covered by a thick layer of Mid-Tertiary felsic volcanic rocks. Normal faulting created a series of horst and graben structures. The grabens were subsequently filled with erosional fragments of the surrounding rocks and now act as alluvial aquifers.

2.3. Hydrogeology

The state of Zacatecas contains 34 alluvial aquifers; 25 of them are endorheic basins that belong to a group called Cuencas Centrales del Norte, and nine that belong to Cuencas Rio Lerma y Santiago and discharge into the Pacific Ocean [34,35]. Large groundwater withdrawals from aquifers surrounding the city of Zacatecas (e.g., Calera, Aguanaval, Chupaderos) for urban, agricultural, and industrial purposes have caused depletion of groundwater levels and altered groundwater flows [5,20,26,36,37,38,39].
The geochemical characteristics vary among aquifers and also within the same aquifer, especially if it is overexploited, like the Calera aquifer [37], where different groundwater flows have been identified, each with a particular water chemistry [27,37,38,39].

2.4. Water Quality Data

Water quality data from Mexico’s National Network for Water Quality [40], which is publicly available online, were used in this study. The database comprised a total of 77 monitoring wells sampled approximately yearly from 2012 to 2021, for a total of 753 water samples. The sampling date was not consistent nor taken during a particular season, but sampling dates for any particular well were at least six months apart. The database did not include well depth. Parameters of interest: As, F−, NO3–N, and associated parameters pH, HCO3, total dissolved solids (TDS), Redox Potential, Cl−, SO42−, Na+, Ca2+, and Mg2+ were extracted from the database. The parameters NO2− and CO32− were negligible (zero value for most of them) and therefore not listed here, but the absence of NO2− attested to the oxidation conditions of the groundwater. The description of the analytical methods utilized in obtaining the data and quality control procedures is provided in Table S1 (Supplementary Materials). Saturation indices (SI) were calculated using Visual Minteq 3.1 software [40].
Of these 77 wells, 54 contained ten or more records and were used for an upward trend analysis. These data are provided in Table S2 in the Supplementary Materials. The location of the sampling sites is shown in Figure 2. The effect of seasonality on trend analyses was estimated by removing the sampling measurements most affected by the rainy season and comparing the recalculated Z with the original Z. The results are shown in Table S4. Because of the significantly different topography, climate, and geology within the study area, the study area was divided into four geographical sections, from which Sections I, II, and III are endorheic basins (Figure 2). Sections I, II, and IV were roughly the same size, but section III was smaller, with only five monitoring wells. However, with 48 data, it was considered well-populated to provide well-supported descriptive statistics.

2.5. Statistical Analyses and Mapping

Concentrations below the detection limit were substituted for one-half of the detection limit for statistical analysis purposes. Spearman correlation coefficients (ρ) were calculated using the RANK.AVE and CORREL functions within MS Excel for Microsoft 360. The significance of ρ was determined using a two-tailed Student’s t-test with n-2 degrees of freedom via an online calculator. The upward trend was calculated according to the Mann–Kendall technique for As, F−, and NO3–N for wells containing 10 records or more since a trend determination requires a minimum of 8–10 observations [40,41]. The Mann–Kendall method determines if there is a trend between the data comprised in a series. This method is made with the creation of a matrix, which is used to calculate the test statistic S (Equation (1).
S = ∑ i = 1 n − 1 ∑ j = 1 n s g n ( X j − X i ) s g n θ = 1     if   θ > 0 0     if   θ = 0 − 1     if   θ < 0
where Xi and Xj are the values of sequence i, j, and n is the length of the time series.
Subsequently, the significance of the trend is evaluated through the calculation of the variance of S, V(S) to obtain the standardized Mann–Kendall statistic Z [42,43] (Equation (2)).
Z = S − 1 V ( S )       S > 0   0                 S = 0 S + 1 V ( S )       S < 0
The value of Z is compared with a critical value (1.96 for a probability of 95%) to determine if the trend is meaningful, and the positive or negative value obtained reflects whether it is an increasing or decreasing trend, respectively. The statistical software Minitab was used for the construction and evaluation of the matrix, which calculates the value of Z directly.
The ArcGIS version 10.8 program was used to construct all maps. To this purpose, the coordinates of the samples were entered into an attribute table using a WGS projection and UTM coordinates (Zone 13). The concentration values of As, F−, and N–NO3 for the year 2020 were added to the attribute table and plotted according to three ranges of concentration.

3. Results and Discussion

3.1. Solute Concentrations

The water quality and Spearman correlation between As–F (for each of sections I to IV) is shown in Table 1, and the 2020 concentration maps in Figure 3. Spearman correlation coefficients showed a weak (ρ < 0.5) but significant (p < 0.01) correlation between As and F− and no correlation for Section III (ρ = 0.116, not significant at p < 0.05). Results for Section III should be interpreted with care as the 48 data belong to only five wells, a small number of wells to fully represent the spatial geochemical variability of the section.
Groundwater in the study area had alkaline conditions and a high evaporation rate, well-known factors that have been related to the presence of As and F [2,10,22,25], for which we will base our discussion on the contributions by lithology and the presence of other ions. The solutes of interest As, F−, NO3–N, and associated parameters varied widely, as revealed by their large range of values (see Table 1). Once separated into the four geographical sections (Figure 2), a particular behavior of solutes emerged, as shown in Table 1. While As, pH, ρ (As–F−), and HCO3 varied little among sections, the other solutes differed greatly in concentrations. For example, Ca concentrations in Section III were five-fold larger than those observed in Sections I and IV.
Apart from Section II, where a concentration effect for all solutes is evident, the western sections (Sections I and IV) had less Ca2+, Na+, SO42−, Mg2+, and TDS than in Section III; however, the concentration of As remained about the same, whereas F− seemed to have its own different pattern (Figure 3). The As behavior points to the outcropping volcanic rocks in the eastern part of the study area as a primary source of dissolved As and F−, with an increasing contribution of carbonate and evaporite rocks in the eastern part of the study area [5]. Na-normalized HCO3 vs. Ca diagrams (known as Gaillardet diagrams) [45] helped to visually depict the contribution of each lithological source to water chemistry. The results (Figure 4) agreed with the lithology of the rocks exposed in each section, confirming that silicates are a main source of solutes in Sections I and IV, an increased contribution of evaporites and carbonates occurs in Section II, and an observed predominant contribution of carbonates in Section III (Table 1 and Figure 3).

3.2. As and F Concentration Patterns

An unexpected result was the low correlation coefficient ρ between As and F− (0.166 to 0.382), despite sharing a common primary source (volcanic rocks). Studies conducted in nearby areas include values of ρ of 0.56 for the Southern High Plains of Texas [25] and 0.26–0.76 for the state of Durango, Mexico [23]. The low ρ value obtained here can be attributed to these solutes taking different paths after their release from volcanic rocks; among them, a stronger affinity to adsorbing to iron oxyhydroxides exhibited by As and a longer residence time of some flow paths within the study area [37].
While As and F− concentrations varied little between Sections I and IV, they both resulted in higher concentrations in Section II. The high evaporation rates that are typical in arid climates, in this case, Section II, is most likely the cause of the increase in all solute concentrations, i.e., As, F−, Na, NO3–N, and TDS, as it has been reported for Mexico [10,23] and elsewhere [21]. In contrast, a sharp decline in F− concentrations concurrent with high Ca concentrations was observed in Section III despite the semiarid climate. Coprecipitation of F− and calcite has been reported [45] as being influenced by the presence of Mg2+. The process seems to be a combination of adsorption and coprecipitation and is favored under the conditions of low F− concentrations and pH > 7.5 [46,47]. A sharp decline of F− concentrations in groundwater oversaturated with calcite was also observed in the bordering state of Durango [23], occurring in an arid area where groundwater was saturated with calcite. To test this hypothesis, saturation indices of groundwater of Section III were calculated utilizing the geochemical code Visual Minteq [41]. The results showed that all wells in Section III were oversaturated with calcite, confirming this possibility.

3.3. Nitrate-N Concentration Pattern

The NO3–N concentrations in Section II were twice the amount of those of Sections I, III, and IV (Table 2) despite similar agricultural activities also occurring in Sections I, III, and IV, validating that evaporation is an important process to solute concentration. Like Section II, Section III has a semiarid climate and high evaporation rate and, as expected, experienced an increase in Ca2+ concentration. However, the concentration of Ca2+ cannot be explained as the dissolution of limestone and/or dolostone alone because of the much larger increase in Ca2+ compared to that of HCO3− shown in Table 1. Dissolution of gypsum (CaSO4∙2H2O) present in the pre-Tertiary carbonates and shales [33,48] was thus needed to account for the large Ca2+ concentrations observed in Section III. The Na-normalized Ca-HCO3 diagrams (Figure 3) provide further support for the presence of evaporites and reinforce the effect of lithology on water chemistry. A similar effect of the dissolution of evaporites has been reported for Durango [23]. In sum, the weathering of silicate minerals constituted the main source of solutes in Sections I to IV, with a larger influence by evaporites and carbonates in Sections II and III, followed by a further concentration of all solutes by evaporation and possibly the result of converging flows of groundwater higher in dissolved salts in Section II.
With respect to the distribution of solutes of interest, the concentration maps (Figure 3) showed a dispersed pattern for As and F− concentrations, with high concentrations of As (>10 µg L−1) scattered over all sections and high concentrations of F− (>1 mg L−1) followed the same behavior, except that they were not present in Section III. This behavior occurring at regional scale will likely change at local scale where concentrated flows (e.g., mining wastes, animal farms) are present The NO3–N concentrations were below the 10 mg L−1 limit except for one well in the northern part of Section II, whereas concentrations >4 mg NO3–N L−1 are prevalent in Section II, which suggest an N input from agricultural and animal wastes that is further concentrated by evaporation and input from flows of groundwater containing a higher concentration of dissolved salts.

3.4. Trend Analysis

Wells with 10 or more data points were used to determine trends and included 42 wells for As, 54 for F−, and 52 for NO3–N. The number of wells considered for trend analysis in each section (I to IV) and trends obtained for these wells (Z value, Mann–Kendall) are listed in Table 2. Table 2 shows that a large proportion of wells are listed as having no trend, and among those with a trend, some had upward and some downward trends. Of the 14 wells having a trend, two had an upward trend for two of the parameters: one well in Section I held upward trends for As and NO3–N, and one well in Section III for F− and NO3–N. Their location is depicted in Figure 5.
Most wells showed no trend (Table 2). Of the 54 wells utilized in trend analyses, only 5 for each As and F− had upward trends, and these wells were scattered over the study area, as shown in Figure 5. The small number of wells with a trend indicates that the effects from anthropogenic and seasonal factors are minor compared to long-term hydrological factors such as weathering of rocks and groundwater residence time. The effect of seasons [35] on water parameters showed a minor effect on statistics Z (Table S4), albeit in a smaller data set of wells. High concentrations of As, F−, and other associated solutes, such as Fe2+ and Mn2+, have been shown to be closely associated with longer groundwater residence time, the latter occurring by mixing of flow from the deeper part of the aquifer [48,49] or at the discharge area [50]. Also, the fact that six wells with a trend occurred in depleted aquifers [35] points to a possible relation between overexploitation and contamination with one or more of these solutes. Since the data are dispersed over a large area containing various climates and lithologies, more studies that constrain the topography, climate, or lithology are needed to determine the precise mechanisms responsible for these effects.
Of the wells showing a NO3–N upward trend, two overlapped with upward trends of either As or F−. Since NO3–N is an anthropogenic solute, this result can be interpreted as contaminated water from the surface infiltrating into the aquifer. Infiltrated surface water consists largely of pumped water [35], which would explain the presence of As and F− besides NO3–N. This is the first study known to the authors, reporting regional concentration trends in northern Mexico.
Overall, the results show that efforts towards adding sustainability to groundwater resources would be more efficient by focusing efforts on two strategies: (1) improving water quality in Section II and (2) reducing the overexploitation of the depleted aquifers. The worst water quality was observed in Section II, with many wells exceeding the recommended limits of As (66% of wells), F− (92% of wells), and NO3–N (22% of wells). Since evaporation was identified as a factor of enrichment in this area, a possible cost-effective treatment to lower the concentration of these solutes would be diluting well water with either collected rainwater or solar-distilled water. The latter seems a feasible option considering the low precipitation and high intensity of solar radiation in the area. Reverse osmosis would remove both As and F−, however, at a higher cost. In addition, the decline in F− concentrations observed in Section II suggests that a treatment based on adding a mixture of lime and gypsum to water will work in this area and would remove part of F− from F−-contaminated wells, keeping in mind that As would not be removed in the process. Although the relationship between concentration and aquifer overexploitation is not fully known, efforts towards reducing the aquifer deficit may alter the intermediate and regional flows enough to improve water quality.

4. Conclusions

Groundwater concentrations of As, F−, and NO3–N in the study area were largely affected by the climate, topography, and lithology of the rocks in contact with water. A conceptual model can be summarized as follows: Felsic volcanic rocks outcropping in the southwest part (Sierra Madre Occidental) contribute to rock fragments that fill the basins in Mesa Central. Weathering of these rocks released As and F− to the water, whereas in the eastern part, exposed sedimentary rocks (carbonates, shales, evaporites) dissolved and provided Na+, Ca2+, Mg2+, Cl−, and SO42+ to the water. Lastly, the warm, arid climate in the central part of the study area (Section II) concentrated the solutes by evaporation, together with converging flows from deeper parts of the aquifer. More studies with climate and lithology variables constrained are needed to verify their effect on As, F−, and NO3–N concentrations. A sharp decline of F− concentration was observed in the semiarid area where groundwater is oversaturated with calcite (Section III), suggesting coprecipitation of F− with calcite. However, more testing is needed to confirm this assumption.
The trend analysis (Mann–Kendall) resulted in a few wells with an upward (or downward) trend, a result interpreted as a relatively stable water quality, a stability that can be preserved by preventing the actions that resulted in affected wells. The large concentrations of geogenic As and F− in some wells will continue to represent a health hazard to the population, a hazard that can be minimized from continued monitoring of wells followed by a conscientious treatment of the wells that show either As, F−, or NO3–N above the recommended guidelines.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/min13091145/s1, Table S1: Parameters, Laboratory analytical procedures and Mexican technical standards, describing analytical methodologies and quality controls considered for the analytical determination of arsenic, fluoride, pH, and physicochemical parameters of water. Table S2: Well water data for Zacatecas. Concentrations in mg L−1, except for alkalinity (Alk), in mg CaCO3 L−1. The Section number (in Roman numeral) is listed below the well number. Source: web site [40]. Table S3: Saturation Indices for well water of Section II. Table S4: Seasonality in the trend analysis.

Author Contributions

Conceptualization, H.M.-d. and M.G.; methodology, H.E.J.-F. and M.G.; software, C.P.C.-C.; validation, H.M.-d., H.E.J.-F. and M.V.E.-A.; formal analysis, H.M.-d.; investigation, H.M.-d.; resources, M.G.; data curation, M.G.; writing—original draft preparation, M.G.; writing—review and editing, H.M.-d., H.E.J.-F., M.V.E.-A. and C.P.C.-C.; visualization, M.G.; supervision, C.P.C.-C. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

All data utilized in this study was extracted from Mexico’s National Network for Water Quality (RENAMECA), publicly available from https://www.gob.mx/conagua/articulos/calidad-del-agua (accessed on 18 June 2023). Additional groundwater information (aquifer location) was obtained from Mexico’s Government site https://www.gob.mx/conagua/acciones-y-programas/zacatecas-74771 (accessed on 18 June 2023).

Acknowledgments

We warmly thank the four reviewers for their comprehensive reviews and insightful comments.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Podgorski, J.; Berg, M. Global threat of arsenic in groundwater. Science 2020, 368, 845–850. [Google Scholar] [CrossRef] [PubMed]
  2. Kumar, M.; Goswami, R.; Patel, A.K.; Srivastava, M.; Das, N. Scenario, perspectives, and mechanism of arsenic and fluoride co-occurrence in the groundwater: A review. Chemosphere 2020, 249, 126126. [Google Scholar] [CrossRef]
  3. Alarcón-Herrera, M.T.; Gutiérrez, M. Geogenic arsenic: Challenges, gaps, and future directions. Curr. Opin. Environ. Sci. Health 2022, 27, 100349. [Google Scholar] [CrossRef]
  4. Nicolli, H.B.; Bundschuh, J.; García, J.W.; Falcón, C.M.; Jean, J.-S. Sources and controls for the mobility of arsenic in oxidizing groundwaters from loess-type sediments in arid/semi-arid dry climates—Evidence from the Chaco-Pampean plain (Argentina). Water Res. 2010, 44, 5589–5604. [Google Scholar] [CrossRef]
  5. Cauich-Kau, D.A.; Cardona-Benavides, A.; Castro-Larragoitia, J.; Rüde, T.R. Understanding Co-Occurrence and Mobility of Uranium and Arsenic Sources IN Groundwater Flow Systems in Semi-Arid Zones in the Mexican Altiplano; European Geosciences Union: Munich, Germany, 2020; p. EGU2020-461. [Google Scholar] [CrossRef]
  6. Blake, J.M.; Walton-Day, K.; Gallegos, T.J.; Yager, D.B.; Teeple, A.; Humberson, D.; Stengel, V.; Becher, K. New geochemical framework and geographicinformation system methodologies to assess element occurrence, persistence, and mobility in groundwater and surface water. Minerals 2022, 12, 411. [Google Scholar] [CrossRef]
  7. Knappett, P.S.K.; Li, Y.; Loza, I.; Hernandez, H.; Avilés, M.; Haaf, D.; Majumder, S.; Huang, Y.; Lynch, B.; Piña, V.; et al. Rising arsenic concentrations from dewatering a geothermally influenced aquifer in central Mexico. Water Res. 2020, 185, 116257. [Google Scholar] [CrossRef]
  8. Bianchini, G.; Brombin, V.; Marchina, C.; Natali, C.; Godebo, T.R.; Rasini, A.; Salani, G.M. Origin of fluoride and arsenic in the Main Ethiopian Rift waters. Minerals 2020, 10, 453. [Google Scholar] [CrossRef]
  9. He, X.; Li, P.; Ji, Y.; Wang, Y.; Su, Z.; Elumalai, V. Groundwater arsenic and fluoride and associated arsenicosis and fluorosis in China: Occurrence, distribution and management. Expos. Health 2020, 12, 355–368. [Google Scholar] [CrossRef]
  10. Alarcón-Herrera, M.T.; Martin-Alarcon, D.A.; Gutiérrez, M.; Reynoso-Cuevas, L.; Martín-Domínguez, A.; Olmos-Márquez, M.A.; Bundschuh, J. Co-occurrence, possible origin, and health-risk assessment of arsenic and fluoride in drinking water sources in Mexico: Geographical data visualization. Sci. Total Environ. 2020, 698, 134168. [Google Scholar] [CrossRef]
  11. González-Horta, C.; Ballinas-Casarrubias, L.; Sánchez-Ramírez, B.; Ishida, M.C.; Barrera-Hernández, A.; Gutiérrez-Torres, D.; Zacarias, O.L.; Saunders, R.J.; Drobná, Z.; Mendez, M.A.; et al. A concurrent exposure to arsenic and fluoride from drinking water in Chihuahua, Mexico. Int. J. Environ. Res. Public Health 2015, 12, 4587–4601. [Google Scholar] [CrossRef]
  12. Martínez-Acuña, M.I.; Mercado-Reyes, M.; Alegría-Torres, J.A.; Mejía-Saavedra, J.J. Preliminary human health risk assessment of arsenic and fluoride in tap water from Zacatecas, México. Environ. Monit. Assess. 2016, 188, 476. [Google Scholar] [CrossRef]
  13. Jiménez-Córdova, M.I.; Sánchez-Peña, L.C.; Barrera-Hernández, A.; González-Horta, C.; Barbier, O.; Del Razo, L.M. Fluoride exposure is associated with altered metabolism of arsenic in an adult Mexican population. Sci. Total Environ. 2019, 684, 621–628. [Google Scholar] [CrossRef] [PubMed]
  14. Fernández-Macías, J.C.; Ochoa-Martínez, A.C.; Orta-García, S.T.; Varela-Silva, J.A.; Pérez-Maldonado, I.N. Probabilistic human health risk assessment associated with fluoride and arsenic co-occurrence in drinking water from the metropolitan area of San Luis Potosi, Mexico. Environ. Monit. Assess. 2020, 192, 712. [Google Scholar] [CrossRef] [PubMed]
  15. Bijay, S.; Craswell, E. Fertilizers and nitrate pollution of surface and ground water: An increasingly pervasive global problem. SN Appl. Sci. 2021, 3, 518. [Google Scholar] [CrossRef]
  16. Hamlin, Q.F.; Martin, S.I.; Kendall, A.D.; Hyndman, D.W. Examining relationships between groundwater nitrate concentrations in drinking water and landscape characteristics to understand health risks. GeoHealth 2022, 6, e2021GH000524. [Google Scholar] [CrossRef]
  17. De León-Gómez, H.; Campo-Delgado, M.A.; Esteller Alberich, M.V.; Velasco-Tapia, F.; Alva-Niño, E.; Cruz López, A. Assessment of nitrate and heavy metal contamination of groundwater using the heavy metal pollution index: Case study of Linares, Mexico. Environ. Earth Sci. 2020, 79, 433. [Google Scholar] [CrossRef]
  18. Diario Oficial de la Federacion, Norma Oficial Mexicana NOM-127-SSA1-2021. Available online: https://www.dof.gob.mx/nota_detalle.php?codigo=5650705&fecha=02/05/2022#gsc.tab=0 (accessed on 23 June 2023).
  19. Gutiérrez, M.; Biagioni, R.; Alarcón-Herrera, M.; Rivas-Lucero, B. An overview of nitrate sources and operating processes in arid and semi in an arid aquifer systems. Sci. Tot. Environ. 2018, 624, 1513–1522. [Google Scholar] [CrossRef]
  20. Ślósarczyk, K.; Witkowski, A.J. Preliminary evaluation of the possible occurrence of pesticides in groundwater contaminated with nitrates—A case study from southern Poland. Water 2021, 13, 3091. [Google Scholar] [CrossRef]
  21. Zhang, X.; Zhao, R.; Wu, X.; Mu, W.; Wu, C. Delineating the controlling mechanisms of arsenic release into groundwater and its associated health risks in the Southern Loess Plateau, China. Water Res. 2022, 219, 118530. [Google Scholar] [CrossRef]
  22. Cauich Kau, D.; Rüde, T.R.; Cardona Benavides, A.; Castro Larragoitia, J. Natural occurrence and controls of arsenic in groundwater in a semiarid basin in the Mexican Altiplano. Hydrogeol. J. 2022, 30, 2459–2477. [Google Scholar] [CrossRef]
  23. Gutiérrez, M.; Alarcón-Herrera, M.T.; Gaytán-Alarcón, M.P. Arsenic and fluorine in northern Mexico, spatial distribution and enrichment factors. Environ. Monit. Asess. 2023, 195, 212. [Google Scholar] [CrossRef]
  24. Sappa, G.; Barbieri, M.; Andrei, F.; Ferranti, F. Assessment of arsenic mobility in a shallow aquifer from Bevera Valley Basin (Northern Italy). Arabian, J. Geosci. 2019, 12, 678. [Google Scholar] [CrossRef]
  25. Scanlon, B.R.; Nicot, J.P.; Reedy, R.C.; Kurtzman, D.; Mukherjee, A.; Nordstrom, D.K. Elevated naturally occurring arsenic in a semiarid oxidizing system, Southern High Plains aquifer, Texas, USA. Appl. Geochem. 2009, 24, 2061–2071. [Google Scholar]
  26. Ortiz-Letechipia, J.; González-Trinidad, J.; Júnez-Ferreira, H.E.; Bautista-Capetillo, C.; Robles-Rovelo, C.O.; Contreras Rodríguez, A.R.; Dávila-Hernández, S. Aqueous arsenic speciation with hydrogeochemical modeling and correlation with fluorine in groundwater in a semiarid region of Mexico. Water 2022, 14, 519. [Google Scholar] [CrossRef]
  27. Avila-Sandoval, C.; Júnez-Ferreira, H.; González-Trinidad, J.; Bautista-Capetillo, C.; Pacheco-Guerrero, A.; Olmos-Trujillo, E. Spatio-temporal analysis of natural and anthropogenic arsenic sources in groundwater flow systems. Int. J. Environ. Res. Public Health 2018, 15, 2374. [Google Scholar] [CrossRef] [PubMed]
  28. Esteller-Alberich, M.V.; Domínguez-Mariani, S.E.; Aviles, M. Groundwater pollution by arsenic and other toxic elements in an abandoned silver mine, Mexico. Environ. Earth Sci. 2015, 74, 2893–2906. [Google Scholar] [CrossRef]
  29. Garbrecht, J.D.; Mojarro, F.; Echavarria-Chairez, F.G.; Bautista-Capetillo, C.F.; Brauer, D.; Steiner, J.L. Sustainable utilization of the Calera aquifer in Zacatecas, Mexico. Appl. Eng. Agric. 2013, 29, 67–75. [Google Scholar] [CrossRef]
  30. Ortega-Guerrero, M.A. Occurrence, distribution, hydrochemistry and origin of arsenic, fluoride and other trace elements dissolved in groundwater at basin scale in central Mexico. Rev. Mex. Ciencias Geol. 2009, 26, 143–161. [Google Scholar]
  31. Armienta, M.A.; Rodríguez, C.R.; Ongley, L.K.; Brust, H.; Morales, F.; Aguayo, A.; Cruz, O.; Ceniceros, O. Origin and fate of arsenic in a historic mining area of Mexico. In Arsenic in Soil and Groundwater Environment; Bhattacharya, P., Mukherjee, A.B., Bundschuh, J., Zevenhoven, R., Loeppert, R.H., Eds.; Trace Metals and other Contaminants in the Environment; Elsevier: Amsterdam, The Netherlands, 2007; Volume 9, pp. 473–498. [Google Scholar]
  32. Nieto-Samaniego, A.F.; Alaniz-Alvarez, S.A.; Camprubí í Cano, A. La Mesa Central: Estratigrafía, estructura y evolución tectónica cenozoica. Bol. Soc. Geol. Mex. 2005, 57, 285–318.29. [Google Scholar] [CrossRef]
  33. Aranda-Gómez, J.J.; Molina-Garza, R.; McDowell, F.W.; Vassallo-Morales, L.F.; Ortega-Rivera, M.A.; Solorio-Munguía, J.G.; Aguillón-Robles, A. The relationship between volcanism and extension in the Mesa Central: The case of Pinos, Zacatecas, Mexico. Rev. Mex. Ciencias Geol. 2007, 24, 16–233. [Google Scholar]
  34. Gobierno de Mexico, Comisión Nacional del Agua. Available online: https://www.gob.mx/conagua/acciones-y-programas/zacatecas-74771 (accessed on 18 June 2023).
  35. CONABIO. Comisión Nacional para el Conocimiento y Uso de la Biodiversidad. In La Biodiversidad en Zacatecas, Estudio de Estado, 1st ed.; Comisión Nacional para el Conocimiento y Uso de la Biodiversidad: Ciudad de Mexico, Mexico, 2020; p. 504. ISBN 978-607-8570-37-9. [Google Scholar]
  36. Nuñez-Peña, E.P.; Escalona-Alcázar, F.J.; Bluhm-Gutiérrez, J.; Ramos-De la Cruz, G.A.; De la Torre-Guerrero, A.; Ortega-Martínez, E.M.; Cardona-Benavides, A. Caracterización hidrogeoquímica del acuífero Jerez, estado de Zacatecas, México. Tecnol. Ciencias Agua 2015, 6, 105–124. [Google Scholar]
  37. de Ávila, H.M.; Júnez-Ferreira, H.E.; González-Trinidad, J.; Esteller-Alberich, M.V.; Silva-Ávalos, R.U.; Dávila-Hernández, S.; Cázares-Escareño, J.; Bautista-Capetillo, C.F. Schematization of converging groundwater flow systems based on 3D geostatistics. Water 2022, 14, 3169. [Google Scholar] [CrossRef]
  38. Ortiz-Letechipia, J.; González-Trinidad, J.; Júnez-Ferreira, H.E.; Bautista-Capetillo, C.; Dávila-Hernández, S. Evaluation of groundwater quality for human consumption and irrigation in relation to arsenic concentration in flow systems in a semi-arid Mexican region. Int. J. Environ. Res. Public Health 2021, 18, 8045. [Google Scholar] [CrossRef]
  39. Rivera-Armendariz, C.A.; Banning, A.; Cardona, A.; Ocampo-Diaz, Y.Z.E.; Castro-Larragoitia, J. Hydrogeochemistry of groundwater in Zacatecas, Mexico: A focus on arsenic, fluoride and uranium. Conference paper. Goldschmidt 2022. [Google Scholar] [CrossRef]
  40. RENAMECA. Water Qual Data from Its Website. 2023. Available online: https://www.gob.mx/conagua/articulos/calidad-del-agua (accessed on 18 June 2023).
  41. Gustafsson, J.P. Visual MINTEQ ver 3.1. Available online: https://vminteq.com/download/ (accessed on 18 June 2023).
  42. Ducci, D.; della Morte, R.; Mottola, A.; Onorati, G.; Pugliano, G. Evaluating upward trends in groundwater nitrate concentrations: An example in an alluvial plain of the Campania region (Southern Italy). Environ. Earth Sci. 2020, 79, 319. [Google Scholar]
  43. Wang, F.; Shao, W.; Yu, H.; Kan, G.; He, X.; Zhang, D.; Ren, M.; Wang, G. Re-evaluation of the power of the Mann-Kendall test for detecting monotonic trends in hydrometeorological time series. Front. Earth Sci. 2020, 8, 0014. [Google Scholar] [CrossRef]
  44. Roberts, R.J.; Irving, E.M. Carta Geológica de la República Mexicana; Mineral Deposits of Central America; U.S. Geological Survey: Reston, VA, USA, 1960; Bulletin 1034. [Google Scholar]
  45. Gaillardet, J.; Dupre, B.; Louvat, P.; Allegre, C.J. Global silicate weathering and CO2 consumption rates deduced from the chemistry of large rivers. Chem. Geol. 1999, 159, 3–30. [Google Scholar] [CrossRef]
  46. Kitano, Y.; Okumura, M. Coprecipitation of fluoride with calcite. Geochem. J. 1973, 7, 37–49. [Google Scholar]
  47. Turner, B.D.; Binning, P.; Stipp, S.L.S. Fluoride removal by calcite: Evidence for fluorite precipitation and surface adsorption. Environ. Sci. Tech. 2005, 39, 9561–9568. [Google Scholar] [CrossRef]
  48. Morán-Ramírez, J.; Ramos-Leal, J.A.; Mahlknecht, J.; Santacruz-DeLeon, G.; Martin-Romero, F.; Fuentes-Rivas, R.M.; Mora, A. Modeling of groundwater processes in a karstic aquifer of Sierra Madre Oriental, Mexico. App. Geochem. 2018, 95, 97–109. [Google Scholar] [CrossRef]
  49. Esteller, M.V.; Kondratenko, N.; Expósito, J.L.; Medina, M.; Martin del Campo, M.A. Hydrogeochemical characteristics of a volcanic-sedimentary aquifer with special emphasis on Fe and Mn content: A case study in Mexico. J. Geochem. Explor. 2017, 180, 113–126. [Google Scholar] [CrossRef]
  50. Espino-Valdés, M.S.; Rodríguez-Lozano, D.F.; Gutiérrez, M.; Silva-Hidalgo, H.; Pinales-Munguía, A. Relationship of Fluoride Concentration to Well Depth in an Alluvial Aquifer in a Semiarid Area. Environments 2022, 9, 155. [Google Scholar] [CrossRef]
Minerals 13 01145 g001
Figure 1. Study area depicting the physiographic provinces: Mesa Central (southern part of Central Plains), Sierra Madre Occidental, Sierra Madre Oriental, and Mexican Volcanic Belt.
Figure 1. Study area depicting the physiographic provinces: Mesa Central (southern part of Central Plains), Sierra Madre Occidental, Sierra Madre Oriental, and Mexican Volcanic Belt.
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Minerals 13 01145 g002
Figure 2. Sections within the study area. Sections I to III contain endorheic basins. Basins in Section IV are exorheic and discharge into the Pacific Ocean.
Figure 2. Sections within the study area. Sections I to III contain endorheic basins. Basins in Section IV are exorheic and discharge into the Pacific Ocean.
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Minerals 13 01145 g003
Figure 3. Concentration maps for As, F−, and NO3–N (2020), with geology background modified from [44].
Figure 3. Concentration maps for As, F−, and NO3–N (2020), with geology background modified from [44].
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Minerals 13 01145 g004
Figure 4. Na-normalized HCO3 vs. Ca diagrams after Gaillardet [45]. Data are shown in blue for Section I, orange for Section II, green for Section III and purple for Section IV.
Figure 4. Na-normalized HCO3 vs. Ca diagrams after Gaillardet [45]. Data are shown in blue for Section I, orange for Section II, green for Section III and purple for Section IV.
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Minerals 13 01145 g005
Figure 5. Location of wells with upward (and downward) trends of As, F−, and NO3–N. Black lines separate the Sections I, II, III, and IV that comprise the study area.
Figure 5. Location of wells with upward (and downward) trends of As, F−, and NO3–N. Black lines separate the Sections I, II, III, and IV that comprise the study area.
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Table 1. Median and range of values (minimum–maximum) of target contaminants and their associated parameters for each section of the study area. Also included are the Spearman correlation coefficient (As-F−) at p < 0.01 and the physiographic characteristics of the sections.
Table 1. Median and range of values (minimum–maximum) of target contaminants and their associated parameters for each section of the study area. Also included are the Spearman correlation coefficient (As-F−) at p < 0.01 and the physiographic characteristics of the sections.
Section ISection IISection IIISection IV
No. data383 (38 wells)130 (14 wells)48 (5 wells)192 (20 wells)
pH7.85 (6.70–8.60)7.90 (7.10–8.94)7.40 (6.60–8.90)7.80 (7.10–8.80)
As, mg L−10.011 (0.0007–0.095)0.019 (0.0007–0.505)0.019 (0.001–0.121)0.012 (0.001–0.138)
F− mg L−11.22 (0.10–4.90)2.38 (0.23–29.60)0.54 (0.22–1.24)2.49 (0.10–8.66)
ρ (As-F)0.2450.363none0.382
NO3–N, mg L−12.03 (0.01–14.91)4.58 (0.01–58.73)2.87 (0.01–10.58)1.35 (0.01–12.61)
Ca2+, mg L−139.2 (14.5–217.7)48.9 (3.1–596.0)192.1 (95.3–407.5)36.3 (11.0–110.6)
Na+, mg L−150.3 (8.1–412.8)163.2 (0.5–1615)80.7 (10.2–881.6)51.8 (11.4–115.3)
Mg2+, mg L−16.9 (0.4–97.4)4.7 (0.5–176.0)29.8 (3.6–85.2)3.1 (0.06–45.1)
HCO3−, mg L−1112.5 (3.7–242.3)122.7 (23.9–510.6)139.7 (82.5–231.2)111.7 (61.0–220.1)
SO42−, mg L−131.1 (2.5–807.6)161.9 (7.5–3966.2)417 (90.3–948.3)21 (5–241)
Cl−, mg L−11.2 (0.1–4.9)34.1 (0.5–765.0)23.2 (12.2–1167.8)12.5 (5.0–108.9)
TDS, mg L−1322 (76–2352)634 (232–7769)894.2 (153.0–3089.7)314 (178–880}
Redox Potential, mV240 (30–722)238 (18–346)244 (27–427)161 (−44–484)
Hydrochemical typeNa-HCO3Na-SO4Ca-SO4Na-HCO3
Relief, land use, climate
Section IMountainous, felsic volcanic rock, urban centers, temperate climate.
Section IILow relief, thick cover of alluvium, rainfed agricultural and cattle-grazing, arid to semiarid.
Section IIIModerate relief, hills of sedimentary and metamorphic rocks, rainfed agricultural and cattle-grazing, temperate climate.
Section IVModerate relief, hills of andesitic volcanic rock, rural, temperate climate.
Table 2. Trends (2012–2021) obtained for As, F−, and NO3–N according to the Mann–Kendall method, significant at p < 0.05.
Table 2. Trends (2012–2021) obtained for As, F−, and NO3–N according to the Mann–Kendall method, significant at p < 0.05.
TrendSection ISection IISection IIISection IV
No. WellsNo. WellsNo. WellsNo. Wells
As
Upward4010
Downward0000
No trend204211
Total No. wells244311
F−
Upward1011
Downward0000
No trend324213
Total No. wells334314
NO3–N
Upward3011
Downward0001
No trend304210
Total No. wells334312
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Morales-deAvila, H.; Gutiérrez, M.; Colmenero-Chacón, C.P.; Júnez-Ferreira, H.E.; Esteller-Alberich, M.V. Upward Trends and Lithological and Climatic Controls of Groundwater Arsenic, Fluoride, and Nitrate in Central Mexico. Minerals 2023, 13, 1145. https://doi.org/10.3390/min13091145

AMA Style

Morales-deAvila H, Gutiérrez M, Colmenero-Chacón CP, Júnez-Ferreira HE, Esteller-Alberich MV. Upward Trends and Lithological and Climatic Controls of Groundwater Arsenic, Fluoride, and Nitrate in Central Mexico. Minerals. 2023; 13(9):1145. https://doi.org/10.3390/min13091145

Chicago/Turabian Style

Morales-deAvila, Heriberto, Mélida Gutiérrez, Claudia Patricia Colmenero-Chacón, Hugo Enrique Júnez-Ferreira, and Maria Vicenta Esteller-Alberich. 2023. "Upward Trends and Lithological and Climatic Controls of Groundwater Arsenic, Fluoride, and Nitrate in Central Mexico" Minerals 13, no. 9: 1145. https://doi.org/10.3390/min13091145

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