Lead, arsenic, mercury and 206 Pb-to- 207 Pb ratio measured in soils from agriculture land sited near mining activity

Lead, arsenic, mercury and 206 Pb-to- 207 Pb ratio measured in soils from agriculture land sited near mining activity | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Lead, arsenic, mercury and 206 Pb-to- 207 Pb ratio measured in soils from agriculture land sited near mining activity Consuelo Letechipia De León, Luis Alberto Cauich-Correa, Irma Cruz Gavilan-Garcia, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9569133/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Due to lead (Pb) in different matrices such as soil, it is vital to estimate its origin due to its impact on public health and food safety of the products generated from agricultural areas near mining activities. This research aimed to determine the presence of Pb and the 206 Pb/ 207 Pb ratio. The sampling (10 samples) and treatment were based on the [ 1 ] and NOM-021-SEMARNAT-2000 [ 2 ] standards. Lead agricultural soils mining isotopic ratio 206Pb/207Pb Figures Figure 1 Figure 2 Figure 3 1 Introduction Heavy metal contamination is a global problem due to its toxicity, long persistence, and bio accumulative nature [ 4 ]. Geogenic sources of heavy metals (such as Pb) come mainly from the decay of radioactive series; on the other hand, anthropogenic activities include heavy metal inputs through the application of fertilizers, organic manures, irrigation, atmospheric deposition, disposal waste, application of sewage and other human activities such as mining [ 5 ]. According to [ 6 ], this contamination represents a significant risk to human health in drinking water and the food chain through plants. Heavy metals and metalloids most frequently studied are Lead (Pb), Arsenic (As), Mercury (Hg), Zinc (Zn), Copper (Cu), Nickel (Ni), Chromium (Cr), and Cadmium (Cd). This list is ranked in descending order of importance of soil contamination. Harmful amounts of heavy metals can enter the human body from contaminated soil through routes of exposure such as direct or indirect ingestion, inhalation, and dermal contact, resulting in effects on human health. In addition, they present ecotoxicity that leads to a deficit in ecological development and bioaccumulation in the food chain [ 7 ]. Pb is one of the essential heavy metals due to its level of contamination and one of the most dispersed in the world because of anthropogenic activities [ 8 ]. It is incorporated into the human body through inhalation, oral and dermal exposure; this last route is much less efficient than the previous two [ 9 ]. On the other hand, the atmosphere is the initial primary receptor, and that anthropogenic sources are at least 1 to 2 orders of magnitude greater than natural sources [ 10 ]. In the terrestrial environment, two types of Pb sources are known: primary and secondary. The primary is from a geogenic origin and is incorporated into the minerals at the time of their formation, and the secondary is of radiogenic origin from the disintegration of Uranium and Thorium [ 11 ]. In nature, Pb has four stable isotopes with different abundances: 204 Pb (1.4%), 206 Pb (24.1%), 207 Pb (22.1%), and 208 Pb (52.4%), however, the relationship between these isotopes varies in different ways. Geological environments since 206 Pb and 207 Pb are formed by the decay of 238 U and 235 U, while 208 Pb is a product of the radioactive decay of 232 Th. 204 Pb is the only natural isotope that is not caused by decay. Therefore, the isotopic composition of Pb is expressed as isotopic ratios 206 Pb / 204 Pb, 208 Pb / 206 Pb, 206 Pb / 207 Pb, the latter being the most common because it can be determined with analytical precision, and the abundance of these isotopes is significant and similar. Furthermore, the abundance of 207 Pb has changed very little over time compared to 206 Pb because the majority of 235 U has declined, while 238 U still has a relatively high abundance on Earth [ 11 ]. Knowing total concentrations and the chemical / mineralogical composition of Pb is not sufficient for an accurate evaluation of the sources of contamination. Therefore, Pb isotopes have been integrated as "fingerprints" of environmental contamination. Since each source of Pb can have different overlapping isotopic ratio ranges. Furthermore, the isotopic composition of Pb in soils reflects mixing, and the distribution of the sources can be quantified in cases where all potential sources of Pb are characterized and have specific relationships. Consequently, isotopic studies of Pb provide a convenient approach to trace its sources in different environmental matrices [ 11 ]. According to [ 12 ], the most recent studies have focused on the characterization of metals contamination, in soils and sediments, near metallurgical, abandoned or operating industrial sites. As well as studies in which it has been possible to determine correlations of concentration of heavy metals and metalloids (Pb, As and Hg) [ 13 ]. Correlation is a method to evaluate a possible bidirectional linear association between two continuous variables. It is measured by a statistic called correlation coefficient, which represents the strength of the linear association between the variables in question. Spearman's rank correlation coefficient is denoted as Rs for a sample statistic. It is appropriate when one or both variables are biased or ordinal (Without normal distribution), the values are in the range between − 1 and 1, the sign only indicates the direction, a good correlation is close to these values [ 14 ]. Contamination consequences include: the degeneration of typical soil functions, poor plant growth, and severe threat to human health [ 12 ]. Zacatecas is a Mexican state where mining activity has a large economic impact; however, near lands for agricultural production there are abandoned or active mining areas representing a risk for soil contamination. This research aims to estimate the lead concentration in agricultural soil sited near to mining activity, and to determine its origin measuring the 206 Pb-to- 207 Pb ratio. In addition, the correlation between Pb and As, Pb and Hg, and As and Hg were analyzed in order to reinforce the fact that these heavy metals are due to mining activity. Table 1 Coordinates of the sampling points. Sample code Coordinates Concentration (mg/kg) North West Pb As Hg M1 23° 10’ 33.7” 102° 56’ 3.8” 38.032 ± 0.253 5.413 ± 0.236 0.230 ± 0.125 M2 23° 10’ 38.8” 102° 56’ 7.4” 30.245 ± 11.214 4.972 ± 0.313 0.674 ± 0.016 M3 23° 10’ 38.8” 102° 56’ 43.6” 47.285 ± 0.772 2.868 ± 0.009 2.687 ± 0.044 M4 23° 10’ 38.0” 102° 55’ 55.9” 22.068 ± 0.365 7.834 ± 1.256 1.808 ± 0.149 M5 23° 10’ 40.0” 102° 55’ 54.8” 30.604 ± 0.503 3.339 ± 0.434 0.152 ± 0.128 M6 23° 10’ 51.8” 102° 55’ 49.1” 31.056 ± 0.561 3.457 ± 0.633 0.241 ± 0.004 M7 23° 10’ 55.6” 102° 55’ 54.8” 22.002 ± 0.630 5.278 ± 0.011 0.194 ± 0.068 M8 23° 10’ 31.5” 102° 55’ 33.2” 29.696 ± 12.351 6.813 ± 0.207 0.492 ± 0.022 M9 23° 10’ 31.7” 102° 55’ 30.4” 38.882 ± 1.118 7.182 ± 0.989 1.168 ± 0.157 M10 23° 10’ 27.5” 102° 55’ 19.9” 39.775 ± 0.305 6.686 ± 0.157 1.403 ± 0.005 Mean of zone 32.965 ± 8.016 5.384 ± 1.744 0.905 ± 0.85 2 Materials and methods 2.1. Study area The present study was carried out in the municipality of Fresnillo, Zacatecas. Study area is approximately 10 5 m 2 (10 hectares) of land used for agricultural purposes. It is at 23° 10' 38.0" latitude, and 102° 55' 55.9" longitude (Fig. 1 ). 2.2. Collection and treatment of samples Ten composite samples were taken using the staggering technique in triplicate in an area of 10 hectares. Table 1 shows the coordinates of the sampling points. The process of the collected samples was based on the [ 1 ] standard, where they were dried at room temperature for 48 hours, ground, and sieved on a 200 mesh. 2.3. Elemental analysis The analysis was carried out in the Environmental Management Laboratory of the Faculty of Chemistry of the National Autonomous University of Mexico, following the U.S. methodologies. EPA. 1996 Method 3050B, U.S. EPA 1992. Method 7061A Arsenic and U.S. EPA 1992. Method 3010A [ 15 – 17 ]. The Pb, As, and Hg concentrations in the soils were measured using the Perkin Elmer Brand Atomic Absorption Spectrometry equipment, Models 3110 and 2380. With the option of combining flame and with a Perkin Elmer brand hydride generator equipment, Model MH515. All the material used for the process was washed with 20% nitric acid and rinsed with deionized water. 2.4 Spearman correlations The Pb-As, Pb-Hg, and As-Hg correlations were determined using the Microsoft Excel program using the Spearman's correlation methods. 2.5. Determination of isotopic ratios of Pb In order to optimize the resource, the isotopic relationships of 3 samples (M3, M4, and M9) were analyzed according to criteria of concentration, distance distribution, and degree of agricultural treatment. The Pb isotopic analysis was carried out at the Ultraclean Laboratory of the Center for Geosciences, UNAM Campus Juriquilla. Soil samples previously pulverized in a porcelain mortar and sieved in 200 mesh were weighed, and 3 g were used, that were digested adding 1 ml of 1N HCl, and was heated to 100 ° C on a thermal grill for 1 hour. The digested soil sample was rinsed three times with deionized water. Subsequently, it was treated with 2 ml of HF. plus and 1 ml of HNO 3 8 N for two days on a thermal grill to 125°C. Finally, two extraction and digestion treatments were carried out with 16N HNO 3 to decompose fluorides [ 18 ]. Sample and the Pb standards (adjusted to 200 ppb) isotopic ratios were measured using a Thermo brand ICP-MS Multicolector model Neptune Plus. Total run blanks (including column chemistry) were 60 pg, which is negligible compared to the concentrations in the tested samples. The analysis of samples and standards consists of 80 static measurement cycles, in measurement cycles of 4 seconds of integration. The beam intensity was 100 V / ppm for 208 Pb, using wet plasma and a 100 ml/min free aspiration nebulizer. The isotopic compositions of Pb were made by static multiple harvesting in the masses 202 to 208. To monitor the fractionation, the NIST SRM 997 standard of a Tl solution was used as an internal reference for the 205 Tl and 203 Tl isotopes with a value of 2.3871. of the instrumental mass, and 202 Hg was monitored to correct for isobaric interference of 204 Hg in 204 Pb using the natural abundances of Hg. The beam intensities measured for 202 Hg were 0.05 mV, so the interference correction at 204 Pb was negligible. To improve reproducibility and precision, samples and standards were prepared on the same day as the analytical session to avoid possible photooxidation of the Tl solution [ 19 ]. They were analyzed with the same Pb / Tl to ensure that the standards and samples effectively conform to the matrix. Finally, the isotopic compositions of Pb corrected by fractionation with Tl of the NISTSRM-981 standard were 206 Pb/ 204 Pb = 16.9302 ± 0.0013, 207 Pb / 204 Pb = 15.4835 ± 0.0012, 208 Pb / 204 Pb = 36.6738 ± 0.0033 and 207 Pb/ 206 Pb = 0.9146 ± 0.0000 [ 20 ]. 3 Results and discussion 3.1. Elemental analysis Pb, As and Hg concentrations were determined in different samples taken from the agricultural soils. In Table 2 are shown the coordinates of sampled soils and the Pb, As and Hg concentrations. Table 2: Results of concentration of Pb, As and Hg. Samples 206 Pb/ 204 Pb 207 Pb/ 204 Pb 208 Pb/ 204 Pb 207 Pb/ 206 Pb M3 18.8550±0.0002 15.6360±0.0002 38.733±0.001 0.830±0.000 M4 18.9100±0.0003 15.6390±0.0003 38.780±0.001 0.827±0.000 M9 18.8260±0.0002 15.6370±0.0002 38.692±0.001 0.831±0.000 The Pb, As and Hg average concentrations in the soil are 32.965 ± 8.016 mg/kg, 5.384 ± 1.744 mg/kg and 0.905 ± 0.85 mg/kg respectively. The Pb mean value are below 4940 and 868.13 mg/kg reported by [21] and [22] respectively. They did the measurements on soils from the state of Zacatecas. The probably explanation of such difference is because [18, 19] analyzed soils heavily contaminated while, [13] analyzed soils rich in heavy metals. According to Table 2 the Pb concentration in the soils is below 400 mg/kg being the maximum concentration acceptable for soils used for agriculture purposes. This limit is defined by the Mexican norm [3], that also defines 22 and 23 mg/kg of As and Hg respectively as limit. 3.2 Statistical and graphical correlations There is a statistical correlation of high concentration of Rs = 0.815 between Pb-Hg at nine sampling points, according to the interpretations established for each correlation analysis reported by [14]. This correlation is represented in Figure 2. Figure 2: Statistical distribution of concentrations of Pb and Hg. The M4 point was discarded by the Mahalanobis method described by [23] since it represents an atypical point. In addition, this point presented difficulties in the methodology of determining its concentration for Hg. Pb, As, and Hg are generally found in mining tailings residues; therefore, the presence of these, even in low concentration, are indicative of their origin in the study areas, as reported by [14]. However, with the previous data, the behavior of the correlation between the combinations Pb-As and As-Hg is different from that found by Pb-Hg; therefore, it cannot be inferred that the source of Pb comes from anthropogenic activity. Specific (Mining) since other possible contributions of exposure such as agrochemicals, water, aerial deposition. It will have to be evaluated; however, it can be inferred that the specific correlation of Pb-Hg in the area is from the same anthropogenic source as reported by [13] for an area with similar characteristics. This was corroborated by a qualitative graphical method that illustrates the correlation distribution between the two heavy metals, Figure 3. Figure 3: Distribution of concentrations of Pb (A), Hg (B), As (C) in the study area. 3.3. Isotopic ratios The data obtained for the evaluations of the isotopic relationships of Pb in samples of agricultural soil for the study area are represented in the following Table 3. Table 3: Results of isotopic ratios. Based on the previous table, the inverse of 207 Pb / 206 Pb was determined to obtain the value of the isotopic ratios 206 Pb / 207 Pb as shown in Table 4. Table 4: Isotopic relationship 206 Pb/ 207 Pb. Samples 206 Pb/ 207 Pb M3 1.205 M4 1.209 M9 1.203 Mean 1.206 ± 0.003 The values obtained for the 206 Pb / 207 Pb isotopic ratio are within the data reported by [24] determined in Cartagena, Spain, where isotopic relationships were obtained in soils of former mining activity, in which it was concluded that as a rule a value above 1.18 is indicative of an anthropogenic source of mining activity. Likewise, our results agree with those reported by [25] in their investigations, who obtained an isotopic ratio of 206 Pb/ 207 Pb of 1.20 in soils of Greece; these authors concluded that the determining isotopic ratio was due to the extraction of sulfur during the Hellenic-Roman era and subsequent mining activities. Based on the above, our study estimates that the source of Pb found in agricultural soil is probably from mining waste spread in the study area. 4 Conclusions The 206 Pb/ 207 Pb isotopic ratio determined, which is a fingerprint of the origin of Pb, shows that these data may come from mining activity, as reported by the consulted literature. In addition, this is corroborated by the existence of a statistical and graphic correlation between the concentration of Pb and that of Hg; therefore, it is estimated that these heavy metals are due to anthropogenic activities (mining tailings) in the entire area of study. However, it is essential to expand the study area, characterize the possible mining tailings, monitor in the different seasons of the year, and evaluate the agrochemicals used in cultivation techniques; this would allow to complete and corroborate the results increase the precision in themselves. Declarations The concentration Pb was analyzed by EAA-F based on EPA methodology: Method 3010A and Method 7061A. On the other hand, four isotopic relationships were analyzed with ICP-MS, the most representative being 206 Pb/ 207 Pb for the study. is due to mining activities carried out near the study area. The average concentration for Pb, As, and Hg was lower than those established by the [3] standard. From the calculation of the correlation between Pb-As-Hg, a significant positive correlation of R 0 = 0.82 was obtained for Pb-Hg, and a 206 Pb/ 207 Pb isotopic ratio of 1.206 ± 0.003. Therefore, it is estimated that the origin of Pb. Author Contribution Consuelo Letechipia de Leon, Conceptualization, Data curation, Methodology, Validation, supervision and writing the draft of the article, paper reviwer and edition. Luis A. Cauich-Correa, Formal data analysis, research, visualization, experimentation. Irma C. Gavilan-Garcia, metodology, measurament chemic analytic samples. Carina O. Torres-Cortes, paper reviwer and edition. Jennifer Ortiz-Letechipia paper reviewer and edition. Acknowledgement To Liliana Corona Martínez head of Centro de Geociencias, Campus UNAM 3001, Juriquilla La Mesa, 76230 Juriquilla, Qro. México for their contribution on the measure of Isotopic relationship 206Pb/207Pb. The authors express their gratitude to the Mexican National Council for Science and Technology (CONACYT) for financing the scholarship of the master students. References Norma Mexicana NMX-, AA-132-SCFI-2016 Muestreo de suelos para la identificación y la cuantificación de metales y metaloides, y manejo de la muestra., Diario Oficial de la Federación, 4 de enero de 2017. Norma Oficial Mexicana NOM-021-RECNAT-2000 Que establece las especificaciones fertilidad, salinidad y clasificación de suelos. 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Washington, DC U.S. EPA (1992) Method 3010A: Acid Digestion of Aqueous Samples and Extracts for Total Metals for Analysis by FLAA or ICP Spectroscopy Revision 1 Washington, DC CARRASCO-NÚÑEZ G, ORTEGA-GUTIÉRREZ F, LANGMUIR GOLDSTEINS, LAGATTA CB, A., GOMEZ-TUENA A (2003) Temporal Control of Subduction Magmatism in the Eastern Trans-Mexican Volcanic Belt: Mantle Sources, Slab Contributions, and Crustal Contamination. Geochemustry Geophysic Geosyst 4:8912 KAMENOV GD, MUELLER PA, PERFIT MR (2004) Optimization of mixed Pb–Tl solutions for high precision isotopic analyses by MC-ICP-MS. J Anal At Spectrom 19:1262–1267 GÓMEZ-TUENA A, DÍAZ-BRAVO B, VÁZQUEZ-DUARTE A, ARVIZU O, MORI L (2013) Andesite petrogenesis by slab-derived plume pollution of a continental rift. Geol Soc Lond Special Publications 385:65–101 SALAS LUEVANO MA, VEGA CARRILLO HR (2016) Environmental impact in a rural community due to a lead recycling plant in Zacatecas, Mexico. Environ Earth Sci 75:408 SALAS LUEVANO MA, MAURICIO CASTILLO JA, GONZÁLEZ RIVERA ML, CARRILLO VEGA, H. R., SALAS MUÑOZ (2017) S. Accumulation and phytostabilization of As, Pb and Cd in plants growing inside mine tailings reforested in Zacatecas, Mexico. Environ Earth Sci, 76(806) MATSUMOTO S, KAMEI Y, MONDEN A, MATSUMOTO K (2007) Comparison of Outlier Detection Methods in Fault-proneness Models. First International Symposium on Empirical Software Engineering and Measurement ESEM Japan, 20–21 Sept. 2007. Nara Institute of Science and Technology, 2007, 461–463 MARGUÍ E, IGLESIAS M, QUERALT I, HIDALGO M (2007) Precise and accurate determination of lead isotope ratios in mining wastes by ICP-QMS as a tool to identify their source. Talanta 73:700–709 CHARALAMPIDES G, MANOLIADIS O (2002) Sr and Pb isotopes as environmental indicators in environmental studies. Environ Int 28:147–151 Tables Tables 3 is not available with this version. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9569133","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":641483907,"identity":"03548781-f5de-40fd-acba-0c4be373b845","order_by":0,"name":"Consuelo Letechipia De 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Pb and Hg.\u003c/p\u003e","description":"","filename":"figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9569133/v1/fc27fb280201c92eeb132401.jpg"},{"id":109760231,"identity":"d8fd665c-89af-4f43-b0a7-44610e3e028f","added_by":"auto","created_at":"2026-05-22 07:28:20","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":22574,"visible":true,"origin":"","legend":"\u003cp\u003eDistribution of concentrations of Pb (A), Hg (B), As (C) in the study area.\u003c/p\u003e","description":"","filename":"figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9569133/v1/2c677981a4cac4fd8e0c0562.jpg"},{"id":109764212,"identity":"c050e780-38f2-45b2-8578-69d5fac02171","added_by":"auto","created_at":"2026-05-22 07:36:45","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":293624,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9569133/v1/d240d773-9b19-4a85-a4a3-67428b0c0b9a.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Lead, arsenic, mercury and 206 Pb-to- 207 Pb ratio measured in soils from agriculture land sited near mining activity","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eHeavy metal contamination is a global problem due to its toxicity, long persistence, and bio accumulative nature [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Geogenic sources of heavy metals (such as Pb) come mainly from the decay of radioactive series; on the other hand, anthropogenic activities include heavy metal inputs through the application of fertilizers, organic manures, irrigation, atmospheric deposition, disposal waste, application of sewage and other human activities such as mining [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. According to [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], this contamination represents a significant risk to human health in drinking water and the food chain through plants.\u003c/p\u003e \u003cp\u003eHeavy metals and metalloids most frequently studied are Lead (Pb), Arsenic (As), Mercury (Hg), Zinc (Zn), Copper (Cu), Nickel (Ni), Chromium (Cr), and Cadmium (Cd). This list is ranked in descending order of importance of soil contamination. Harmful amounts of heavy metals can enter the human body from contaminated soil through routes of exposure such as direct or indirect ingestion, inhalation, and dermal contact, resulting in effects on human health. In addition, they present ecotoxicity that leads to a deficit in ecological development and bioaccumulation in the food chain [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePb is one of the essential heavy metals due to its level of contamination and one of the most dispersed in the world because of anthropogenic activities [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. It is incorporated into the human body through inhalation, oral and dermal exposure; this last route is much less efficient than the previous two [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eOn the other hand, the atmosphere is the initial primary receptor, and that anthropogenic sources are at least 1 to 2 orders of magnitude greater than natural sources [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. In the terrestrial environment, two types of Pb sources are known: primary and secondary. The primary is from a geogenic origin and is incorporated into the minerals at the time of their formation, and the secondary is of radiogenic origin from the disintegration of Uranium and Thorium [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In nature, Pb has four stable isotopes with different abundances: \u003csup\u003e204\u003c/sup\u003ePb (1.4%), \u003csup\u003e206\u003c/sup\u003ePb (24.1%), \u003csup\u003e207\u003c/sup\u003ePb (22.1%), and \u003csup\u003e208\u003c/sup\u003ePb (52.4%), however, the relationship between these isotopes varies in different ways. Geological environments since \u003csup\u003e206\u003c/sup\u003ePb and \u003csup\u003e207\u003c/sup\u003ePb are formed by the decay of \u003csup\u003e238\u003c/sup\u003eU and \u003csup\u003e235\u003c/sup\u003eU, while \u003csup\u003e208\u003c/sup\u003ePb is a product of the radioactive decay of \u003csup\u003e232\u003c/sup\u003eTh. \u003csup\u003e204\u003c/sup\u003ePb is the only natural isotope that is not caused by decay. Therefore, the isotopic composition of Pb is expressed as isotopic ratios \u003csup\u003e206\u003c/sup\u003ePb / \u003csup\u003e204\u003c/sup\u003ePb, \u003csup\u003e208\u003c/sup\u003ePb / \u003csup\u003e206\u003c/sup\u003ePb, \u003csup\u003e206\u003c/sup\u003ePb / \u003csup\u003e207\u003c/sup\u003ePb, the latter being the most common because it can be determined with analytical precision, and the abundance of these isotopes is significant and similar. Furthermore, the abundance of \u003csup\u003e207\u003c/sup\u003ePb has changed very little over time compared to \u003csup\u003e206\u003c/sup\u003ePb because the majority of \u003csup\u003e235\u003c/sup\u003eU has declined, while \u003csup\u003e238\u003c/sup\u003eU still has a relatively high abundance on Earth [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eKnowing total concentrations and the chemical / mineralogical composition of Pb is not sufficient for an accurate evaluation of the sources of contamination. Therefore, Pb isotopes have been integrated as \"fingerprints\" of environmental contamination. Since each source of Pb can have different overlapping isotopic ratio ranges. Furthermore, the isotopic composition of Pb in soils reflects mixing, and the distribution of the sources can be quantified in cases where all potential sources of Pb are characterized and have specific relationships. Consequently, isotopic studies of Pb provide a convenient approach to trace its sources in different environmental matrices [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAccording to [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], the most recent studies have focused on the characterization of metals contamination, in soils and sediments, near metallurgical, abandoned or operating industrial sites. As well as studies in which it has been possible to determine correlations of concentration of heavy metals and metalloids (Pb, As and Hg) [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Correlation is a method to evaluate a possible bidirectional linear association between two continuous variables. It is measured by a statistic called correlation coefficient, which represents the strength of the linear association between the variables in question. Spearman's rank correlation coefficient is denoted as Rs for a sample statistic. It is appropriate\u003c/p\u003e \u003cp\u003ewhen one or both variables are biased or ordinal (Without normal distribution), the values are in the range between \u0026minus;\u0026thinsp;1 and 1, the sign only indicates the direction, a good correlation is close to these values [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Contamination consequences include: the degeneration of typical soil functions, poor plant growth, and severe threat to human health [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eZacatecas is a Mexican state where mining activity has a large economic impact; however, near lands for agricultural production there are abandoned or active mining areas representing a risk for soil contamination.\u003c/p\u003e \u003cp\u003eThis research aims to estimate the lead concentration in agricultural soil sited near to mining activity, and to determine its origin measuring the \u003csup\u003e206\u003c/sup\u003ePb-to-\u003csup\u003e207\u003c/sup\u003ePb ratio. In addition, the correlation between Pb and As, Pb and Hg, and As and Hg were analyzed in order to reinforce the fact that these heavy metals are due to mining activity.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCoordinates of the sampling points.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"13\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSample code\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eCoordinates\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"6\" nameend=\"c9\" namest=\"c4\"\u003e \u003cp\u003eConcentration (mg/kg)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c13\" namest=\"c10\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNorth\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWest\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003ePb\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003eAs\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003eHg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c13\" namest=\"c10\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u0026deg; 10\u0026rsquo; 33.7\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e102\u0026deg; 56\u0026rsquo; 3.8\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e38.032\u0026thinsp;\u0026plusmn;\u0026thinsp;0.253\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e5.413\u0026thinsp;\u0026plusmn;\u0026thinsp;0.236\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e0.230\u0026thinsp;\u0026plusmn;\u0026thinsp;0.125\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u0026deg; 10\u0026rsquo; 38.8\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e102\u0026deg; 56\u0026rsquo; 7.4\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e30.245\u0026thinsp;\u0026plusmn;\u0026thinsp;11.214\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e4.972\u0026thinsp;\u0026plusmn;\u0026thinsp;0.313\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e0.674\u0026thinsp;\u0026plusmn;\u0026thinsp;0.016\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u0026deg; 10\u0026rsquo; 38.8\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e102\u0026deg; 56\u0026rsquo; 43.6\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e47.285\u0026thinsp;\u0026plusmn;\u0026thinsp;0.772\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e2.868\u0026thinsp;\u0026plusmn;\u0026thinsp;0.009\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e2.687\u0026thinsp;\u0026plusmn;\u0026thinsp;0.044\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u0026deg; 10\u0026rsquo; 38.0\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e102\u0026deg; 55\u0026rsquo; 55.9\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e22.068\u0026thinsp;\u0026plusmn;\u0026thinsp;0.365\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e7.834\u0026thinsp;\u0026plusmn;\u0026thinsp;1.256\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e1.808\u0026thinsp;\u0026plusmn;\u0026thinsp;0.149\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u0026deg; 10\u0026rsquo; 40.0\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e102\u0026deg; 55\u0026rsquo; 54.8\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e30.604\u0026thinsp;\u0026plusmn;\u0026thinsp;0.503\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e3.339\u0026thinsp;\u0026plusmn;\u0026thinsp;0.434\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e0.152\u0026thinsp;\u0026plusmn;\u0026thinsp;0.128\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u0026deg; 10\u0026rsquo; 51.8\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e102\u0026deg; 55\u0026rsquo; 49.1\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e31.056\u0026thinsp;\u0026plusmn;\u0026thinsp;0.561\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e3.457\u0026thinsp;\u0026plusmn;\u0026thinsp;0.633\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e0.241\u0026thinsp;\u0026plusmn;\u0026thinsp;0.004\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u0026deg; 10\u0026rsquo; 55.6\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e102\u0026deg; 55\u0026rsquo; 54.8\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e22.002\u0026thinsp;\u0026plusmn;\u0026thinsp;0.630\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e5.278\u0026thinsp;\u0026plusmn;\u0026thinsp;0.011\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e0.194\u0026thinsp;\u0026plusmn;\u0026thinsp;0.068\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u0026deg; 10\u0026rsquo; 31.5\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e102\u0026deg; 55\u0026rsquo; 33.2\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e29.696\u0026thinsp;\u0026plusmn;\u0026thinsp;12.351\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e6.813\u0026thinsp;\u0026plusmn;\u0026thinsp;0.207\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e0.492\u0026thinsp;\u0026plusmn;\u0026thinsp;0.022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u0026deg; 10\u0026rsquo; 31.7\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e102\u0026deg; 55\u0026rsquo; 30.4\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e38.882\u0026thinsp;\u0026plusmn;\u0026thinsp;1.118\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e7.182\u0026thinsp;\u0026plusmn;\u0026thinsp;0.989\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e1.168\u0026thinsp;\u0026plusmn;\u0026thinsp;0.157\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u0026deg; 10\u0026rsquo; 27.5\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e102\u0026deg; 55\u0026rsquo; 19.9\u0026rdquo;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e39.775\u0026thinsp;\u0026plusmn;\u0026thinsp;0.305\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e6.686\u0026thinsp;\u0026plusmn;\u0026thinsp;0.157\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e1.403\u0026thinsp;\u0026plusmn;\u0026thinsp;0.005\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003eMean of zone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e32.965\u0026thinsp;\u0026plusmn;\u0026thinsp;8.016\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e5.384\u0026thinsp;\u0026plusmn;\u0026thinsp;1.744\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003e0.905\u0026thinsp;\u0026plusmn;\u0026thinsp;0.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"2 Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Study area\u003c/h2\u003e \u003cp\u003eThe present study was carried out in the municipality of Fresnillo, Zacatecas. Study area is approximately 10\u003csup\u003e5\u003c/sup\u003e m\u003csup\u003e2\u003c/sup\u003e (10 hectares) of land used for agricultural purposes. It is at 23\u0026deg; 10' 38.0\" latitude, and 102\u0026deg; 55' 55.9\" longitude (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Collection and treatment of samples\u003c/h2\u003e \u003cp\u003eTen composite samples were taken using the staggering technique in triplicate in an area of 10 hectares.\u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the coordinates of the sampling points. The process of the collected samples was based on the [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] standard, where they were dried at room temperature for 48 hours, ground, and sieved on a 200 mesh.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Elemental analysis\u003c/h2\u003e \u003cp\u003eThe analysis was carried out in the Environmental Management Laboratory of the Faculty of Chemistry of the National Autonomous University of Mexico, following the U.S. methodologies. EPA. 1996 Method 3050B, U.S. EPA 1992. Method 7061A Arsenic and U.S. EPA 1992. Method 3010A [\u003cspan additionalcitationids=\"CR16\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe Pb, As, and Hg concentrations in the soils were measured using the Perkin Elmer Brand Atomic Absorption Spectrometry equipment, Models 3110 and 2380. With the option of combining flame and with a Perkin Elmer brand hydride generator equipment, Model MH515. All the material used for the process was washed with 20% nitric acid and rinsed with deionized water.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Spearman correlations\u003c/h2\u003e \u003cp\u003eThe Pb-As, Pb-Hg, and As-Hg correlations were determined using the Microsoft Excel program using the Spearman's correlation methods.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Determination of isotopic ratios of Pb\u003c/h2\u003e \u003cp\u003eIn order to optimize the resource, the isotopic relationships of 3 samples (M3, M4, and M9) were analyzed according to criteria of concentration, distance distribution, and degree of agricultural treatment.\u003c/p\u003e \u003cp\u003eThe Pb isotopic analysis was carried out at the Ultraclean Laboratory of the Center for Geosciences, UNAM Campus Juriquilla. Soil samples previously pulverized in a porcelain mortar and sieved in 200 mesh were weighed, and 3 g were used, that were digested adding 1 ml of 1N HCl, and was heated to 100 \u0026deg; C on a thermal grill for 1 hour. The digested soil sample was rinsed three times with deionized water. Subsequently, it was treated with 2 ml of HF. plus and 1 ml of HNO\u003csub\u003e3\u003c/sub\u003e 8 N for two days on a thermal grill to 125\u0026deg;C. Finally, two extraction and digestion treatments were carried out with 16N HNO\u003csub\u003e3\u003c/sub\u003e to decompose fluorides [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSample and the Pb standards (adjusted to 200 ppb) isotopic ratios were measured using a Thermo brand ICP-MS Multicolector model Neptune Plus. Total run blanks (including column chemistry) were 60 pg, which is negligible compared to the concentrations in the tested samples. The analysis of samples and standards consists of 80 static measurement cycles, in measurement cycles of 4 seconds of integration. The beam intensity was 100 V / ppm for \u003csup\u003e208\u003c/sup\u003ePb, using wet plasma and a 100 ml/min free aspiration nebulizer.\u003c/p\u003e \u003cp\u003eThe isotopic compositions of Pb were made by static multiple harvesting in the masses 202 to 208. To monitor the fractionation, the NIST SRM 997 standard of a Tl solution was used as an internal reference for the \u003csup\u003e205\u003c/sup\u003eTl and \u003csup\u003e203\u003c/sup\u003eTl isotopes with a value of 2.3871. of the instrumental mass, and \u003csup\u003e202\u003c/sup\u003eHg was monitored to correct for isobaric interference of \u003csup\u003e204\u003c/sup\u003eHg in \u003csup\u003e204\u003c/sup\u003ePb using the natural abundances of Hg. The beam intensities measured for \u003csup\u003e202\u003c/sup\u003eHg were 0.05 mV, so the interference correction at \u003csup\u003e204\u003c/sup\u003ePb was negligible. To improve reproducibility and precision, samples and standards were prepared on the same day as the analytical session to avoid possible photooxidation of the Tl solution [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. They were analyzed with the same Pb / Tl to ensure that the standards and samples effectively conform to the matrix. Finally, the isotopic compositions of Pb corrected by fractionation with Tl of the NISTSRM-981 standard were \u003csup\u003e206\u003c/sup\u003ePb/\u003csup\u003e204\u003c/sup\u003ePb\u0026thinsp;=\u0026thinsp;16.9302\u0026thinsp;\u0026plusmn;\u0026thinsp;0.0013, \u003csup\u003e207\u003c/sup\u003ePb / \u003csup\u003e204\u003c/sup\u003ePb\u0026thinsp;=\u0026thinsp;15.4835\u0026thinsp;\u0026plusmn;\u0026thinsp;0.0012, \u003csup\u003e208\u003c/sup\u003ePb / \u003csup\u003e204\u003c/sup\u003ePb\u0026thinsp;=\u0026thinsp;36.6738\u0026thinsp;\u0026plusmn;\u0026thinsp;0.0033 and \u003csup\u003e207\u003c/sup\u003ePb/\u003csup\u003e206\u003c/sup\u003ePb\u0026thinsp;=\u0026thinsp;0.9146\u0026thinsp;\u0026plusmn;\u0026thinsp;0.0000 [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e"},{"header":"3 Results and discussion","content":"\u003cp\u003e\u003cstrong\u003e3.1. Elemental analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePb, As and Hg concentrations were determined in different samples taken from the agricultural soils. In Table 2 are shown the coordinates of sampled soils\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eand the Pb, As and Hg concentrations.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2:\u003c/strong\u003e Results of concentration of Pb, As and Hg.\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eSamples\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003csup\u003e206\u003c/sup\u003ePb/\u003csup\u003e204\u003c/sup\u003ePb\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003csup\u003e207\u003c/sup\u003ePb/\u003csup\u003e204\u003c/sup\u003ePb\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003csup\u003e208\u003c/sup\u003ePb/\u003csup\u003e204\u003c/sup\u003ePb\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003csup\u003e207\u003c/sup\u003ePb/\u003csup\u003e206\u003c/sup\u003ePb\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eM3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e18.8550\u0026plusmn;0.0002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e15.6360\u0026plusmn;0.0002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e38.733\u0026plusmn;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.830\u0026plusmn;0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eM4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e18.9100\u0026plusmn;0.0003\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e15.6390\u0026plusmn;0.0003\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e38.780\u0026plusmn;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.827\u0026plusmn;0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eM9\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e18.8260\u0026plusmn;0.0002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e15.6370\u0026plusmn;0.0002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e38.692\u0026plusmn;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.831\u0026plusmn;0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe Pb, As and Hg average concentrations in the soil are 32.965 \u0026plusmn; 8.016 mg/kg, 5.384 \u0026plusmn; 1.744 mg/kg and 0.905 \u0026plusmn; 0.85 mg/kg respectively. The Pb mean value are below 4940 and 868.13 mg/kg reported by [21] and [22] respectively. They did the measurements on soils from the state of Zacatecas. The probably explanation of such difference is because [18, 19] analyzed soils heavily contaminated while, [13] analyzed soils rich in heavy metals.\u003c/p\u003e\n\u003cp\u003eAccording to Table 2 the Pb concentration in the soils is below 400 mg/kg being the maximum concentration acceptable for soils used for agriculture purposes. This limit is defined by the Mexican norm [3], that also defines 22 and 23 mg/kg of As and Hg respectively as limit.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2 Statistical and graphical correlations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere is a statistical correlation of high concentration of Rs = 0.815 between Pb-Hg at nine sampling points, according to the interpretations established for each correlation analysis reported by [14]. This correlation is represented in Figure 2.\u003cv:shapetype id=\"_x0000_t75\" coordsize=\"21600,21600\" o:spt=\"75\" o:preferrelative=\"t\" path=\"m@4@5l@4@11@9@11@9@5xe\" filled=\"f\" stroked=\"f\"\u003e\u0026nbsp;\u003cv:stroke joinstyle=\"miter\"\u003e\u0026nbsp;\u003cv:formulas\u003e\u0026nbsp;\u003cv:f eqn=\"if lineDrawn pixelLineWidth 0\"\u003e\u0026nbsp;\u003cv:f eqn=\"sum @0 1 0\"\u003e\u0026nbsp;\u003cv:f eqn=\"sum 0 0 @1\"\u003e\u0026nbsp;\u003cv:f eqn=\"prod @2 1 2\"\u003e\u0026nbsp;\u003cv:f eqn=\"prod @3 21600 pixelWidth\"\u003e\u0026nbsp;\u003cv:f eqn=\"prod @3 21600 pixelHeight\"\u003e\u0026nbsp;\u003cv:f eqn=\"sum @0 0 1\"\u003e\u0026nbsp;\u003cv:f eqn=\"prod @6 1 2\"\u003e\u0026nbsp;\u003cv:f eqn=\"prod @7 21600 pixelWidth\"\u003e\u0026nbsp;\u003cv:f eqn=\"sum @8 21600 0\"\u003e\u0026nbsp;\u003cv:f eqn=\"prod @7 21600 pixelHeight\"\u003e\u0026nbsp;\u003cv:f eqn=\"sum @10 21600 0\"\u003e\u0026nbsp;\u003c/v:f\u003e\u0026nbsp;\u003c/v:f\u003e\u0026nbsp;\u003c/v:f\u003e\u0026nbsp;\u003c/v:f\u003e\u0026nbsp;\u003c/v:f\u003e\u0026nbsp;\u003c/v:f\u003e \u0026nbsp;\u003c/v:f\u003e \u0026nbsp;\u003c/v:f\u003e \u0026nbsp;\u003c/v:f\u003e \u0026nbsp;\u003c/v:f\u003e \u0026nbsp;\u003c/v:f\u003e \u0026nbsp;\u003c/v:f\u003e \u0026nbsp;\u003c/v:formulas\u003e\n \u003cv:path o:extrusionok=\"f\" gradientshapeok=\"t\" o:connecttype=\"rect\"\u003e\u0026nbsp;\u003c/v:path\u003e\u0026nbsp; \u0026nbsp;\u0026nbsp;\n \u003c/v:stroke\u003e \u0026nbsp;\u003c/v:shapetype\u003e\n\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 2:\u003c/strong\u003e Statistical distribution of concentrations of Pb and Hg.\u003c/p\u003e\n\u003cp\u003eThe M4 point was discarded by the Mahalanobis method described by [23] since it represents an atypical point. In addition, this point presented difficulties in the methodology of determining its concentration for Hg.\u003c/p\u003e\n\u003cp\u003ePb, As, and Hg are generally found in mining tailings residues; therefore, the presence of these, even in low concentration, are indicative of their origin in the study areas, as reported by [14]. However, with the previous data, the behavior of the correlation between the combinations Pb-As and As-Hg is different from that found by Pb-Hg; therefore, it cannot be inferred that the source of Pb comes from anthropogenic activity. Specific (Mining) since other possible contributions of exposure such as agrochemicals, water, aerial deposition. It will have to be evaluated; however, it can be inferred that the specific correlation of Pb-Hg in the area is from the same anthropogenic source as reported by [13] for an area with similar characteristics.\u003c/p\u003e\n\u003cp\u003eThis was corroborated by a qualitative graphical method that illustrates the correlation distribution between the two heavy metals, Figure 3.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 3:\u003c/strong\u003e Distribution of concentrations of Pb (A), Hg (B), As (C) in the study area.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.3. Isotopic ratios\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data obtained for the evaluations of the isotopic relationships of Pb in samples of agricultural soil for the study area are represented in the following Table 3.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3:\u003c/strong\u003e Results of isotopic ratios.\u003c/p\u003e\n\u003cp\u003eBased on the previous table, the inverse of \u003csup\u003e207\u003c/sup\u003ePb / \u003csup\u003e206\u003c/sup\u003ePb was determined to obtain the value of the isotopic ratios \u003csup\u003e206\u003c/sup\u003ePb / \u003csup\u003e207\u003c/sup\u003ePb as shown in Table 4.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4:\u003c/strong\u003e Isotopic relationship \u003csup\u003e206\u003c/sup\u003ePb/\u003csup\u003e207\u003c/sup\u003ePb.\u003c/p\u003e\n\u003ctable\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eSamples\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003csup\u003e206\u003c/sup\u003ePb/\u003csup\u003e207\u003c/sup\u003ePb\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eM3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.205\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eM4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.209\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eM9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.203\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.206 \u0026plusmn; 0.003\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eThe values obtained for the \u003csup\u003e206\u003c/sup\u003ePb / \u003csup\u003e207\u003c/sup\u003ePb isotopic ratio are within the data reported by [24] determined in Cartagena, Spain, where isotopic relationships were obtained in soils of former mining activity, in which it was concluded that as a rule a value above 1.18 is indicative of an \u0026nbsp;anthropogenic source of mining activity.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eLikewise, our results agree with those \u0026nbsp; reported by [25] in their investigations, \u0026nbsp;who obtained an isotopic ratio of \u003csup\u003e206\u003c/sup\u003ePb/\u003csup\u003e207\u003c/sup\u003ePb of 1.20 in soils of Greece; these authors concluded that the determining isotopic ratio was due to the extraction of sulfur during the Hellenic-Roman era and subsequent mining\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eactivities. Based on the above, our study estimates that the source of Pb found in agricultural soil is probably from mining waste spread in the study area.\u003c/p\u003e"},{"header":"4 Conclusions","content":"\u003cp\u003eThe \u003csup\u003e206\u003c/sup\u003ePb/ \u003csup\u003e207\u003c/sup\u003ePb isotopic ratio determined, which is a fingerprint of the origin of Pb, shows that these data may come from mining activity, as reported by the consulted literature. In addition, this is corroborated by the existence of a statistical and graphic correlation between the concentration of Pb and that of Hg; therefore, it is estimated that these heavy metals are due to anthropogenic activities (mining tailings) in the entire area of study. However, it is essential to expand the study area, characterize the possible mining tailings, monitor in the different seasons of the year, and evaluate the agrochemicals used in cultivation techniques; this would allow to complete and corroborate the results increase the precision in themselves.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eThe concentration Pb was analyzed by EAA-F based on EPA methodology: Method 3010A and Method 7061A. On the other hand, four isotopic relationships were analyzed with ICP-MS, the most representative being \u003csup\u003e206\u003c/sup\u003ePb/\u003csup\u003e207\u003c/sup\u003ePb for the study. is due to mining activities carried out near the study area. The average concentration for Pb, As, and Hg was lower than those established by the [3] standard. From the calculation of the correlation between Pb-As-Hg, a significant positive correlation of R\u003csub\u003e0\u003c/sub\u003e = 0.82 was obtained for Pb-Hg, and a \u003csup\u003e206\u003c/sup\u003ePb/\u003csup\u003e207\u003c/sup\u003ePb isotopic ratio of 1.206 \u0026plusmn; 0.003. Therefore, it is estimated that the origin of Pb.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eConsuelo Letechipia de Leon, Conceptualization, Data curation, Methodology, Validation, supervision and writing the draft of the article, paper reviwer and edition. Luis A. Cauich-Correa, Formal data analysis, research, visualization, experimentation. Irma C. Gavilan-Garcia, metodology, measurament chemic analytic samples. Carina O. Torres-Cortes, paper reviwer and edition. Jennifer Ortiz-Letechipia paper reviewer and edition.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eTo Liliana Corona Mart\u0026iacute;nez head of Centro de Geociencias, Campus UNAM 3001, Juriquilla La Mesa, 76230 Juriquilla, Qro. M\u0026eacute;xico for their contribution on the measure of Isotopic relationship 206Pb/207Pb. The authors express their gratitude to the Mexican National Council for Science and Technology (CONACYT) for financing the scholarship of the master students.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eNorma Mexicana NMX-, AA-132-SCFI-2016 Muestreo de suelos para la identificaci\u0026oacute;n y la cuantificaci\u0026oacute;n de metales y metaloides, y manejo de la muestra., Diario Oficial de la Federaci\u0026oacute;n, 4 de enero de 2017.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNorma Oficial Mexicana NOM-021-RECNAT-2000 Que establece las especificaciones fertilidad, salinidad y clasificaci\u0026oacute;n de suelos. Estudios, muestro y an\u0026aacute;lisis, Diario Oficial de la Federaci\u0026oacute;n, 31 de diciembre 2002\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNorma Oficial Mexicana NOM-147-SEMARNAT/SSA 1-2004 que establese criterios para determinar las concentraciones de remediaci\u0026oacute;n de suelo contaminado por ars\u0026eacute;nico, bario, berilio, cadmio, cromo hexavalente, mercurio, niquel, plata, plomo, selenio, talio y/o vanadio. Procuradur\u0026iacute;a Federal de Protecci\u0026oacute;n al Ambiente, 13 de Septiembre de 2016.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLIU H, LIU G, WANG S, YUAN ZHOUC, Z., DA C (2018) Distribution of heavy metals, stable isotope ratios (δ13C and δ15N) and risk assessment of fish from the Yellow River Estuary, China. 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Environ Pollut 231:1188\u0026ndash;1200\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCHENG H, HU Y (2010) Lead (Pb) isotopic fingerprinting and its applications in lead pollution studies in China: A review. Environ Pollut 158:1134\u0026ndash;1146\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eATSDR (2007) Toxicological profile for Lead. \u003cem\u003eAtlanta, GA: U.S. Department of Health and Human Services\u003c/em\u003e. Public Health Service Agency Toxic Substances Disease Registry\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKOM\u0026Aacute;REK M, ETTLER V, CHRASTN\u0026Yacute; V, MIHALJEVIČ M (2008) Lead isotopes in environmental sciences: A review. Environ Int 34:562\u0026ndash;577\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKABATA-PENDIAS A (2000) Trace elements in soils and plants, 3\u0026ndash; edn. CRC, ed. Boca Raton\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKONG J, WEI GUOQ, STRAUSS R, ZHU H, LI G, SONG S, CHEN Z, SONG T, B., ZHOU, T., ZHENG G (2018) Contamination of heavy metals and isotopic tracing of Pb in surface and profile soils in a polluted farmland from a typical karst area in southern China. Sci Total Environ, 637\u0026ndash;638, 1035\u0026ndash;1045\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSANTOS-SANTOS E, YARTO-RAM\u0026Iacute;REZ M, IRMA GAVIL\u0026Aacute;N-GARC\u0026Iacute;A JC-D, GAVIL\u0026Aacute;N-GARC\u0026Iacute;A A, REN\u0026Eacute;-ROSILES SS, VILLEGAS TL (2006) Analysis of Arsenic, Lead and Mercury in Farming Areas with Mining Contaminated Soils at Zacatecas, Mexico. Chem Soc 50:57\u0026ndash;63\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMUKAKA MM, Statistics Corner (2012) A guide to appropriate use of Correlation coefficient in medical research. 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Accumulation and phytostabilization of As, Pb and Cd in plants growing inside mine tailings reforested in Zacatecas, Mexico. Environ Earth Sci, 76(806)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMATSUMOTO S, KAMEI Y, MONDEN A, MATSUMOTO K (2007) Comparison of Outlier Detection Methods in Fault-proneness Models. \u003cem\u003eFirst International Symposium on Empirical Software Engineering and Measurement\u003c/em\u003eESEM Japan, 20\u0026ndash;21 Sept. 2007. Nara Institute of Science and Technology, 2007, 461\u0026ndash;463\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMARGU\u0026Iacute; E, IGLESIAS M, QUERALT I, HIDALGO M (2007) Precise and accurate determination of lead isotope ratios in mining wastes by ICP-QMS as a tool to identify their source. Talanta 73:700\u0026ndash;709\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCHARALAMPIDES G, MANOLIADIS O (2002) Sr and Pb isotopes as environmental indicators in environmental studies. Environ Int 28:147\u0026ndash;151\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"Tables 3 is not available with this version."}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Lead, agricultural soils, mining, isotopic ratio 206Pb/207Pb","lastPublishedDoi":"10.21203/rs.3.rs-9569133/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9569133/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eDue to lead (Pb) in different matrices such as soil, it is vital to estimate its origin due to its impact on public health and food safety of the products generated from agricultural areas near mining activities. This research aimed to determine the presence of Pb and the \u003csup\u003e206\u003c/sup\u003ePb/\u003csup\u003e207\u003c/sup\u003ePb ratio. The sampling (10 samples) and treatment were based on the [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] and NOM-021-SEMARNAT-2000 [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] standards.\u003c/p\u003e","manuscriptTitle":"Lead, arsenic, mercury and 206 Pb-to- 207 Pb ratio measured in soils from agriculture land sited near mining activity","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-18 18:33:41","doi":"10.21203/rs.3.rs-9569133/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"271e7b55-b5bc-4bcd-a235-09a8c9927787","owner":[],"postedDate":"May 18th, 2026","published":true,"recentEditorialEvents":[{"type":"reviewerAgreed","content":"330021411063793779209269653317454889662","date":"2026-05-07T11:15:41+00:00","index":15,"fulltext":""},{"type":"reviewerAgreed","content":"7304284841882771481685174346306805244","date":"2026-05-07T09:54:41+00:00","index":14,"fulltext":""},{"type":"reviewersInvited","content":"8","date":"2026-05-07T09:38:52+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-18T18:33:41+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-18 18:33:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9569133","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9569133","identity":"rs-9569133","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}