Evaluation of the application of Aquatic Humic Substances as a remediation technique for the removal of metals from water bodies

Evaluation of the application of Aquatic Humic Substances as a remediation technique for the removal of metals from water bodies | 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 Evaluation of the application of Aquatic Humic Substances as a remediation technique for the removal of metals from water bodies MARIA DE JESUS GONZALEZ GUADARRAMA, Silvia Elena Castillo Blum, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7031857/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 In this work, we studied the potential effects of aquatic humic substances on the water concentrations of major and trace elements in aquatic systems to evaluate their possible use as an alternative to heavy metals’ pollution. Daphnia magna was used as a control for the test organisms. Aquatic humic substances are the first reservoir of carbon in freshwater bodies. To assess their potential as a remediation technique through complex formation, their physicochemical properties must be evaluated as a first step. This study was carried out to characterise the AHS compounds formed with Cu, Mn, Pb and Zn, corroborate their stability under natural conditions, and evaluate their potential for in situ or ex situ removal of heavy metals from aquatic systems. The results indicate that the studied metal humates (Cu, Mn, Pb and Zn) are soluble at an acidic pH (< 4) and insoluble at a neutral or alkaline pH. The decomposition temperature for all compounds (metal humates) exceeds 573.15 K, indicating that they are stable under normal environmental conditions. It was also identified that aquatic humic substances radically decrease the access of heavy metals to organisms, and, modify the concentrations of nutrients in the water which can impact the development of organisms, making direct application unviable. The technique can be applied to wastewater before it is discharged into water bodies. Results indicate that: the coordination compounds (metal humates) formed are stable in environmental conditions and this technique can be applied as a pretreatment or ex situ remediation process. Aquatic humic substances aquatic systems heavy metals nutrients remediation techniques Figures Figure 1 Figure 2 Introduction Excessive exploitation and unequal worldwide water distribution represent a challenge for humanity, which had led various organizations such as United Nations (UN) to seek agreements and take action to improve the global situation. It is reported that by 2023,4.2 billion people lack safely managed drinking water, 2.2 billion do not have access to drinking water, of which 771 million may have access to water from systems such as private wells, rivers or lakes. The World Health Organization and the United Nations Children's Fund suggest that nearly 400,000 infant deaths could be avoided worldwide if water, sanitation, and hygiene conditions were improved. According to the UN, water scarcity is increasing; in 2019, 2 billion people lived in countries with this problem (UN, 2019). According to the United Nations Office for Disaster Risk Reduction (UNISDR), 90% of natural disasters are water-related. Furthermore, nearly 80% of wastewater returns to the ecosystem untreated or not reused (UN Water, 2018). The contamination of water bodies due to human activities is one of the main challenges because poor water quality is a global problem for ecosystems and for various activities such as agriculture, animal husbandry and human consumption. Among these activities; we find industrial, mining, and domestic activities, which can generate the presence of heavy metals, most of which represent a risk to organisms (Verma and Dwivedi, 2013 ; Priti and Paul, 2016 ; Wang et al., 2022 ). Generally, remediation techniques involve expensive and complex processes, which complicate their application. Then, we should seek simple, economical, and easily accessible techniques and environmentally friendly methods for wastewater treatment, thus improving the trophic status of water bodies. This will be reflected in the sustainable use of water. (De Shampheraere & Janssen, 2002; Forest et al., 2007 ; Goulet et al., 2007 ; Serrano Balderas et al., 2016; Ali & Khan, 2018; Chouvelon et al., 2019 ; Fang et al., 2019 ). Within the implementation of remediation techniques, the study of their ecotoxicology is required, which implies the evaluation of the physicochemical stability of the compounds, in addition to the possible interactions with the components within a body of water, analyzing the chemical speciation and even identifying the effect that the technique could have on organisms and nutrient distribution. (Maradona et al., 2012; Tan & Wang, 2014; Griffiths et al., 2021). Organisms such as D. magna (Cladocera) due to their abundance in both salty and fresh systems, easy reproduction (parthenogenetic), life cycle and adaptability have been widely used in studies on the toxicity of various organic compounds, such as drugs and their metabolites, besides being participants in tests on the evaluation of metals involving bioaccessibility, tolerance and genetic alterations, (De Schamphelaere et al., 2004; De Schamphelaere & Janssen, 2004; Núñez & Hurtado, 2005; Neves et al., 2015; Sertz et al., 2015). Once the ecotoxicological characteristics of a proposed remediation technique have been identified, the process can be analyzed and the ex-situ or in-situ application mode can be defined, considering also the characteristics of the system to be remediated, whether it is wastewater, what type of flow predominates, laminar or turbulent, type of mixture, temperature (Margalef, 1983). It is worth mentioning that in Mexico, the Ministry of the Environment and Natural Resources (SEMARNAT) indicates that the control organisms to be used for these studies are Daphnia magna. Among the remediation techniques to remove metals are Aquatic Humic Substances (AHS), which are the main reservoir of organic carbon in limnological systems and several studies have shown that these compounds can react with halogens, pesticides, fertilizers, and metals to form compounds that modify the distribution, accessibility and even toxicity (Chen et al. 2007 ; Liu et al. 201; González-Guadarrama et al. 2018 ; González-Guadarrama 2018 ). From the ecotoxicological point of view, to apply a remediation technique, it is necessary, in the case of chemical methods, to identify the chemical species formed, solubility, melting or decomposition temperature, as well as the possible interaction with living beings, to verify the feasibility of application (Wetzel, 2001 ). AHS are no exception, and it is necessary to determine the characteristics of humates and the effect they will have on the distribution of major and trace elements within water bodies (Davidge et al., 2001 ). Trace metals can be considered essential, essential-toxic or toxic depending on their concentration, chemical speciation and relationship with the metabolic processes of organisms (Crossgrove & Zheng, 2004 ; Kumar, 2012). It is also important to study the reactivity of essential metals towards AHS, since their concentration is determinant for organisms (Rodwell, 2019). It is important to identify an adequate method to ensure that the concentration of toxic essential metals do not exceed the limits established by national and international drinking water standards. Among the metals that belong to this classification are Cu, Mn, Cr, Zn, Co, Fe, Mo, Mg, Ca, Na and K (Ali et al., 2019 , NOM-127-SSA1-2021, ONU, Agua, 2023). It is necessary to study the compounds' characteristics and evaluate the method's pertinence to use this remediation method; therefore, the objectives of this work are to determine the solubility and melting or decomposition temperature of copper, manganese, lead, zinc, and polymetallic humates, and to determine their stability under environmental conditions. In addition to elucidating the effects of AHS on the distribution of major elements (cationic) and trace elements within a water body, using as test organisms D magna. Materials and methods The experimental part is divided into three parts, the first consists of the formation and isolation of the humates with each metal (Cu, MN, Pb and Zn), and the second corresponds to the determination of solubility in distilled water at neutral, acidic ( 7) pH, in addition to the determination of melting or decomposition temperatures of the compounds using Fischer-Jhons equipment. The third part is focused on the analysis of the interaction between the major (cations) and trace elements with AHS, and the possible effects on their distribution within the water bodies, D. magna were used as test organisms. These organisms were selected according their life span and reproduction, the species has been indicated for environmental tests. In this specific case, D. magna was only included to identify the effect of the formation of metallic humates on metal bioavailability. For the development of this part, it was necessary to acquire the organisms and allow them to acclimatize to the environmental conditions and synthetic water for the experiments. To later use the organisms for the different systems in the same development conditions. To prepare the synthetic water with the necessary nutrients for the optimal development of Daphnia, NaHCO 3 (Sigma), CaCl 2· 2H 2 O (Meyer), MgSO 4 ·2H 2 O (Merck), and KCl (Aldrich) were added, as recommended by Huamán-Tenorio (2017), spinach juice was also added, which represents a rich source of chlorophylls, a food indicated for microcrustaceans, as proposed by previous studies (Núñez and Hurtado 2005; Tan and Wang 2014). It is essential to note that all experiments were conducted in triplicate. The water used for the experiments was collected from the spring present in San Bartolo Morelos, State of Mexico, at coordinates 19°47'13'' N and 99°40'04'' W, the water sample was conditioned as previously indicated with the nutrients required for the experiments, to inoculate and cultivate the D. magna, and allow for their adaptation. Once the organisms were adapted, the experiment was continued as follows. Three systems were set up to compare the availability of metals in the presence or absence of AHS and a control system to monitor the organisms: 1) System 1 or control, in which only the necessary nutrients were added. 2) System 2, containing the nutrients and heavy metals (Cu, Mn, Zn and Pb from a solution with a concentration of 500 mgL-1 for each element). 3) System 3 in which the AHS solution (100 mgL-1) and the solution of the metallic mixture described in system 2 were added. According to the life span of the organisms, the duration of the experiment was 10 days. For the experiment, 50 adult organisms were placed in each system. Initial water samples were taken to verify the initial concentrations of major (cations) and trace elements. For the analysis of the organisms and their access to metals, after 10 days, 20 organisms were isolated from each of the systems and dried at room temperature, then digested with concentrated nitric acid for two hours and gauged to 25 mL with deionized water, and stored for later analysis. All concentrations were determined by ICP-OES (Inductively Coupled Plasma Atomic Emission Spectroscopy). These analyses were carried out with the Perkin-Elmer Optima 8300 DV equipment with S10 Perkin-Elmer Atomic Spectroscopy autosampler at the Atomic Spectroscopy Laboratory of the Institute of Geology of UNAM. The analytical conditions for each element are: Limit of Quantification (LQ) for Ca (0.072 mg L-1), Cu (0.033 mg L-1), K (0.446 mg L-1), Mg (0.030 mg L-1), Mn (0.001 mg L-1), Na (0. 188 mg L-1) and Zn (0.004 mg L-1) with uncertainty values for Ca (4.08%), Cu (1.88%), K (3.69%), Mg (4.01%), Mn (4.44%), Na (3.38%) and Zn (4. 01%). The mean and standard deviation values of the results were calculated using an Excel spreadsheet, as well as to determine the reproducibility, uncertainty, and error. Results The solubility determined for all the coordination compounds between metals and AHS in deionized water is around 10 − 8 g L − 1 , as can be seen in Table 1 . Meanwhile, the results of the solubility tests with pH variation indicate that in an acid medium (pH 7.0) the compounds are insoluble). It was found that the coordination compounds do not melt but show decomposition temperature, which for all the compounds is higher than 573.15 K Table 1 Solubility results for each of the compounds formed in deionized water Compound Solubility in deionized water (g L − 1 ) AHS-Cu 3.85X10 − 8 AHS-Mn 1.92X10 − 8 AHS-Pb 1.81X10 − 7 AHS-Zn 2.44X10 − 8 AHS-Cu-Mn-Pb-Zn 3.76X10 − 8 The concentration values for the metals in solution at the beginning and at the end of the experiments obtained by ICP-OES analysis can be seen in Table 2 . Table 2 Concentrations of major and trace elements in water for the three systems analyzed at the beginning of the experiment. Ion/System System 1(mgL − 1 ) System 2(mgL − 1 ) System 3(mgL − 1 ) Na + 74.59 74.59 74.59 K + 33.99 33.99 33.99 Ca 2+ 51.57 51.57 51.57 Mg 2+ 36.55 36.55 36.55 Cu <LD 0.414 0.414 Mn 0.105 0.561 0.561 Pb <LD 0.403 0.403 Zn 0.008 0.579 0.576 LD = Detection limit The concentration of major and trace elements of the D. magna from the three systems post-experiment can be seen in Figs. 1 and 2 . These figures show how the presence of AHS changes the interaction between organisms with major and trace elements. The use of spinach juice may represent the cause of the slight enrichment of Mn, while the organisms contain Cu and Pb naturally as observed in the control. The final concentration of the elements in the three systems can be seen in the Table 3 . Table 3 Concentrations of the metals in solution at the end of the experiment. System 1: control (nutrients only), System 2: nutrients and heavy metals, System 3: nutrients, heavy metals and AHS solution Ion/System System 1 (mgL − 1 ) System 2 (mgL − 1 ) System 3 (mgL − 1 ) Na + 66.79 65.129 67.78 K + 33.99 31.21 29.57 Ca 2+ 51.57 61.03 45.36 Mg 2+ 36.55 32.35 31.08 Cu <LD <LD 0.046 Mn 0.085 0.345 0.049 Pb <LD <LD <LD Zn 0.008 0.236 0.076 Discussion The solubility results show that the compounds are insoluble in alkaline and neutral media, so under normal water body conditions and considering the pH established by the standards for drinking water and water bodies between 6 and 9 (NOM-127-SSA1-2021 and NOM-001-SEMARNAT-2021) they would precipitate, which means that the metals would be eliminated or their concentration in the water column would be reduced. However, physical factors such as turbulent flow or waves can resuspend the compounds and make the metals bioaccessible. While at acidic pH the compounds formed are completely soluble, which means that if an event such as an acid spill or acidification of the water bodies occurs, the compounds would be soluble, which would allow the metals to be reincorporated into the water column. Another factor to consider regarding the low solubility is that other pollutants could co-precipitate in water bodies, which would be beneficial for water treatment, nevertheless also nutrients, which would not be adequate for organisms. As for the decomposition temperature of the compounds, it can be highlighted that, being so high, they suggest high stability in environmental conditions, so AHS can be an effective method to reduce or eliminate metal contamination in natural environments or in wastewater. As can be observed and according to the studies previously reported by González-Guadarrama et al. ( 2018 ) a considerable decrease in metal concentration in the water to the initial value of each system occurred, thus the heavy metals lessen more than 90% for Cu, Mn and Pb, while for Zn it is reduced by about 85%. This decrease in concentrations of metals shows that AHS have the capacity to react with all metals, so they are an excellent alternative for treating water polluted with metals, since the removal is multi-elemental, as can be seen by comparing the concentrations reported in Tables 1 and 3 . An important contribution to the presence of manganese in all systems is spinach juice, since it was detected in the control system samples while it was absent in the natural samples without conditioning. The reaction products between AHS and major or trace elements in natural waters provide relevant information on the behavior of metals. Previous studies (Liu et al. 2010 ) indicate that major elements can react with AHS and reduce their bioavailability. However, what we observed here, is that the presence of AHS affects in different ways the availability of cations since Na concentration increased in system 3, possibly due to its natural presence in the AHS and/or the isolation process (Thurman and Malcom, 1981) that uses a NaOH solution. The results obtained with the test organisms indicate, according to Figs. 2 and 3, that the presence of AHS and metals modifies the intake capacity. Daphnia reduces potassium intake by almost 90% in the presence of metals and metals with AHS, compared to the control system, and in the case of magnesium by almost 50% in the presence of metals and 40% in the presence of metals and AHS, also compared to the control system. In the case of Ca, an inverse situation is observed, with a 52% increase in intake in the presence of metals and 40% in the presence of trace metals and AHS, which may be a reflection of the contribution of the AHS themselves and the characteristics of the exoskeleton. In the case of sodium, the behavior depends on the other species present; when only other metals are present, its intake decreases by up to 30% and when AHS are also present, it decreases by 5%, as can be seen in Fig. 2 . It can be said that the presence of AHS affects the assimilation of nutrients as indicated by Kazmierczak et al. (2011), also the availability of nutrients, as well as trace metals, which would be reflected in the development and life cycle of organisms, in this case the D. Magna. The results obtained indicate that AHS in water bodies may represent a conflict, because they not only decrease the concentrations of heavy metals, but also modify the interaction between organisms and heavy metals, but also with nutrients, which can be seen in Figs. 1 and 2 , such modifications could be reflected in damage to the organisms limiting their access to the ideal concentrations to carry out metabolic processes These effects and interactions constrain the application of AHS directly in water bodies as a remediation technique. According to Fig. 2 , it is observed that the D. magna do not have elevated concentrations of heavy metals, but AHS modify the uptake of metals by organisms both in terms of nutrients and trace elements present in water bodies, so its use as a remediation technique should be restricted to pretreatment or to an ex-situ method. The described experimental results suggest that the use of AHS is an effective method to remove metals from wastewater as an ex-situ treatment, since within the water bodies they can react with nutrients and modify their bioavailability. Situation that could explain the trophic status of polyhumic lakes in Poland, which despite having high concentrations of AHS as their name suggests are oligotrophic, corresponding to low nutrient concentration and low presence of organisms (Kazmierczak et al., 2011; Ejankowski and Iglinska, 2014; Du Preez and Wepener, 2016). AHS can then be considered to avoid the dispersion of heavy metals into the environment at sites such as mine tailings or in the elimination or decrease within the water column at wastewater discharge sites and would greatly improve water quality and its return to the environment. Conclusions AHS are an excellent alternative for removing metals from wastewater, so using them as a remediation technique is a great option, as they are used as a pretreatment prior to discharge into natural water bodies. The compounds formed under ambient conditions are stable, according to their decomposition temperature and solubility pH, which is low (≤ 4) and is not recommended for use in drinking water or wastewater according to the standards. The reactions are favored and the products precipitate due to their low solubility, which could cause them to co-precipitate other compounds present in the wastewater. Declarations This work was supported by scholarship. Grant number 71/2020 Author María de Jesús González Guadarrama has received research support from DGAPA, UNAM Competing Interests The authors have no relevant financial or non-financial interests to disclose. Author contributions All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by María de Jesús González Guadarrama. The first draft of the manuscript was written by María de Jesús González Guadarrama and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Acknowledgments I thank the Postdoctoral Fellowship Program of the DGAPA of UNAM. The technical support of Javier Tadeo M. Sc., Patricia Fierro Biol., Karla Patricia Salas Martin Dr., Olivia Cruz Ronquillo QFB, Alejandra Aguayo Ríos M. Ing., and Omar Neri Hernández QFB. Data Availability The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request References Ali H, Khan E. (2019) Trophic transfer, bioaccumulation and biomagnification of non-essential hazardous heavy metals and metalloids in food chains/webs-concepts and implications for wildlife and human health. Human and Ecological risk. Assessment 25:6, 1353-1376. https://doi.org/10.1080/10807039.2018.1469398 Ali, H., Khan, E., & Ilahi, I. (2019). Environmental chemistry and ecotoxicology of hazardous heavy metals: environmental persistence, toxicity, and bioaccumulation. Journal of chemistry , 2019 (1), 6730305. https://doi.org/10.1155/2019/6730305 Chen C., Wang X., Jiang H., Hu W., (2007) Direct observation of macromolecular structures of humic acid by AFM and SEM . Colloids and surface A: Physicochem. Eng. Aspects, 302; 121-125. https://doi.org/10.1016/j.colsurfa.2007.02.014 Chouvelon T, Strady E, Harmelin-Vivien M, Radakovith O, Brach-Pap C, Crochet S, Knoery J, Rozuel E, Thomas B, Tronezynski J, Chiffdeau H, (2019) Patterns of trace metals bioaccumulation and trophic transfer in a phytoplankton-zooplankton-small pelagic fish marine food web. Marine Pollution Bulletin. 146;1013-1030. https://doi.org/10.1016/j.marpolbul.2019.07.047 Crossgrove J., Zheng W. (2004) Manganese toxicity upon overexposure. NMR IN BIOMEDICINE, 17, 8; 544-553. https://doi.org/10.1002/nbm.931 Davidge J., Thomas C. P. Williams D. R. (2001) Conditional formation constants or chemical speciation data?Chemical speciation and Bioavailability, 13, 4; 129-134. https://doi.org/10.3184/095422901782775390 De Forest D.K. Brix K.V. Adams W.J. (2007) Assessing metal bioaccumulation in aquatic environments: The inverse relationship between bioaccumulation factors, trophic transfer factors and exposure concentration, Aquatic Toxicology, 84, 236-246. https://doi.org/10.1016/j.aquatox.2007.02.022 De Shamphelaere KC., Janssen CR (2004) Effects of Dissolved Organic Carbon Concentration and Source, pH, and water hardness on chronic toxicity of copper to Daphnia Magna. Environ Toxicol and Chem, 23;5,1115-1122. https://doi.org/10.1897/02-593. Fang T, Lu W, Cui K, Li J, Yang K, Zhao X, Liang Y, Li H., (2019), Distribution, bioaccumulation and trophic transfer of trace metals in the food web of Chaohu Lake, Anhui, China, Chemosphere, 218, 1122-1130. https://doi.org/10.1016/j.chemosphere.2018.10.107 Gandara, M., Galdino, R. L., & Caraballo, P. (2013). Historia de vida de Daphnia magna y Ceriodaphnia reticulata en condiciones de laboratorio: uso potencial como alimento para peces. Revista Colombiana de Ciencia Animal , 5 (2), 340-357. https://doi.org/10.24188/recia.v5.n2.2013.447 González-Guadarrama MJ. (2018) Interacción de Sustancias Húmicas Acuáticas con As, Cu, Mn y Zn. (Tesis doctoral) Universidad Nacional Autónoma de México. González-Guadarrama MJ, Armienta-Hernández MA, Rosa A H (2018), Aquatic Humic Substances: Relationship Between Origin and Complexing Capacity. Bull Environ Contam Toxicol 100, 627–633. DOI 10.1007/s00128-018-2318-4 Goulet RR., Krack S, Doyle PJ., Have, L, Vigneault B, McGeer JC, (2007) Dynamic multipathway modelling of Cd bioaccumulation in Daphnia magna using waterborne and diet borne exposures. Aquatic Toxicology, 81; 117-125. https://doi.org/10.1016/j.aquatox.2006.11.008. Huamán Tenorio, V. (2017). Crecimiento poblacional de Daphnia magna “pulga de agua” en cultivo experimental alimentado con Saccharomyces cerevisiae “levadura” y jugo de Spinacia oleracea “espinaca”. (Tesis de Licenciatura) http://repositorio.unsch.edu.pe/handle/UNSCH/1657 Kumar G. V., Nayak A., Agarwal S., Dobhal R., Prasada. D., Singh P., Sharma B., Tyagi S., Singh R. (2012) Arsenic speciation analysis and remediation techniques in drinking water. Taylor &Francois, 40;231-243. https://doi.org/10.1016/S1001-0742(09)60308-9 Liu J., Wang J., Chen Y., Lippold H., Lippman-Pipke J. (2010) Comparative characterisation of two natural humic acids in the Pearl River Basin, China and their environmental implications . J. of Environmental Sciences, 22, 11; 1695-1702. https://doi.org/10.1016/S1001-0742(09)60308-9 Priti, P., & Paul, B. (2016). Assessment of heavy metal pollution in water resources and their impacts: A review. Journal of Basic and Applied Engineering Research , 3 (8), 671-675. Thurman, E. M., & Malcolm, R. L. (1981). Preparative isolation of aquatic humic substances. Environmental science & technology , 15 (4), 463-466. Verma, R., & Dwivedi, P. (2013). Heavy metal water pollution-A case study. Recent research in Science and Technology , 5 (5). Wang, Z., Luo, P., Zha, X., Xu, C., Kang, S., Zhou, M., ... & Wang, Y. (2022). Overview assessment of risk evaluation and treatment technologies for heavy metal pollution of water and soil. Journal of Cleaner Production , 379 , 134043.https://doi.org/10.1016/j.jclepro.2022.134043. Wetzel, R.G. (2001) Limnology. Lake and River Ecosystems. 3a ed. Ed Elsevier. We USA. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7031857","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":480192572,"identity":"3748ee6c-0a05-4174-9f04-3a1fd5290995","order_by":0,"name":"MARIA DE JESUS GONZALEZ GUADARRAMA","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA70lEQVRIiWNgGAWjYDACCRA2sJFjbG9gYCZei0VBmjFzzwFStFR8OJzYPiOBSC38s3vMJG4YMBvzznxj+LmgwoaBv707gelmGx5L7pwxk5xhwCYnOTvHWHrGmTQGiTNnNzDnnMGtxUAix0xawoDH2HB2joE0b9thoEguUEsFAS1/DCQS9988Y/wbocUAvxYJCQODxMYZPGbE2SJxI63YQsIgwZixJ63MmudMGg/IL4fx+YV/RvLGGxJ//gOj8vDm2zwVNnL87b0bH+fiCTEgYJGA0Bxg9/OAiAN4NTAwMH+A0OwPCCgcBaNgFIyCkQoALrdMY/2dn80AAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0003-1804-352X","institution":"Universidad Nacional Autonoma de Mexico","correspondingAuthor":true,"prefix":"","firstName":"MARIA","middleName":"DE JESUS GONZALEZ","lastName":"GUADARRAMA","suffix":""},{"id":480192573,"identity":"8162074d-a7a6-4616-8b6a-10eb50cc95e5","order_by":1,"name":"Silvia Elena Castillo Blum","email":"","orcid":"","institution":"Universidad Nacional Autonoma de Mexico Facultad de Quimica","correspondingAuthor":false,"prefix":"","firstName":"Silvia","middleName":"Elena Castillo","lastName":"Blum","suffix":""},{"id":480192574,"identity":"91dd4482-2d60-446b-8a5a-58fb3bbf51a4","order_by":2,"name":"María Aurora Armienta-Hernández","email":"","orcid":"","institution":"UNAM IGEF: Universidad Nacional Autonoma de Mexico Instituto de Geofisica","correspondingAuthor":false,"prefix":"","firstName":"María","middleName":"Aurora","lastName":"Armienta-Hernández","suffix":""}],"badges":[],"createdAt":"2025-07-02 17:59:09","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7031857/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7031857/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":86196172,"identity":"cd1b7165-62df-484c-8b85-9155dfbdba40","added_by":"auto","created_at":"2025-07-07 21:35:53","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":36531,"visible":true,"origin":"","legend":"\u003cp\u003eGraph showing the change in concentration of major elements with D. magna in the different systems: System 1: control (nutrients only), System 2: nutrients and heavy metals (Cu, Zn, Mn, Pb) System 3: nutrients, heavy metals and AHS solution. Dice elemento en el eje x. Cambar a element\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7031857/v1/aeb412ead01a12635eff5853.png"},{"id":86196044,"identity":"1d2f2eaf-b4e0-4b96-bc09-a517739bbf03","added_by":"auto","created_at":"2025-07-07 21:27:53","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":25563,"visible":true,"origin":"","legend":"\u003cp\u003eGraph showing the comparison of the concentration of trace metals in D. magna from the following systems: System 1: control (nutrients only), System 2: nutrients and heavy metals (Cu, Zn, Mn, Pb) System 3: nutrients, heavy metals and AHS solution\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7031857/v1/75762c1474aa6074c97bfcbc.png"},{"id":92781961,"identity":"678d59e4-a2be-4ff6-90c8-af3f700e703f","added_by":"auto","created_at":"2025-10-04 18:29:53","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":516634,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7031857/v1/200d6c37-5f11-4b95-9c2c-e98257fd5b2c.pdf"}],"financialInterests":"","formattedTitle":"Evaluation of the application of Aquatic Humic Substances as a remediation technique for the removal of metals from water bodies","fulltext":[{"header":"Introduction","content":"\u003cp\u003eExcessive exploitation and unequal worldwide water distribution represent a challenge for humanity, which had led various organizations such as United Nations (UN) to seek agreements and take action to improve the global situation. It is reported that by 2023,4.2\u0026nbsp;billion people lack safely managed drinking water, 2.2\u0026nbsp;billion do not have access to drinking water, of which 771\u0026nbsp;million may have access to water from systems such as private wells, rivers or lakes. The World Health Organization and the United Nations Children's Fund suggest that nearly 400,000 infant deaths could be avoided worldwide if water, sanitation, and hygiene conditions were improved.\u003c/p\u003e\u003cp\u003eAccording to the UN, water scarcity is increasing; in 2019, 2\u0026nbsp;billion people lived in countries with this problem (UN, 2019). According to the United Nations Office for Disaster Risk Reduction (UNISDR), 90% of natural disasters are water-related. Furthermore, nearly 80% of wastewater returns to the ecosystem untreated or not reused (UN Water, 2018).\u003c/p\u003e\u003cp\u003eThe contamination of water bodies due to human activities is one of the main challenges because poor water quality is a global problem for ecosystems and for various activities such as agriculture, animal husbandry and human consumption. Among these activities; we find industrial, mining, and domestic activities, which can generate the presence of heavy metals, most of which represent a risk to organisms (Verma and Dwivedi, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Priti and Paul, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Wang et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eGenerally, remediation techniques involve expensive and complex processes, which complicate their application. Then, we should seek simple, economical, and easily accessible techniques and environmentally friendly methods for wastewater treatment, thus improving the trophic status of water bodies. This will be reflected in the sustainable use of water. (De Shampheraere \u0026amp; Janssen, 2002; Forest et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Goulet et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Serrano Balderas et al., 2016; Ali \u0026amp; Khan, 2018; Chouvelon et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Fang et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eWithin the implementation of remediation techniques, the study of their ecotoxicology is required, which implies the evaluation of the physicochemical stability of the compounds, in addition to the possible interactions with the components within a body of water, analyzing the chemical speciation and even identifying the effect that the technique could have on organisms and nutrient distribution. (Maradona et al., 2012; Tan \u0026amp; Wang, 2014; Griffiths et al., 2021).\u003c/p\u003e\u003cp\u003eOrganisms such as D. magna (Cladocera) due to their abundance in both salty and fresh systems, easy reproduction (parthenogenetic), life cycle and adaptability have been widely used in studies on the toxicity of various organic compounds, such as drugs and their metabolites, besides being participants in tests on the evaluation of metals involving bioaccessibility, tolerance and genetic alterations, (De Schamphelaere et al., 2004; De Schamphelaere \u0026amp; Janssen, 2004; N\u0026uacute;\u0026ntilde;ez \u0026amp; Hurtado, 2005; Neves et al., 2015; Sertz et al., 2015).\u003c/p\u003e\u003cp\u003eOnce the ecotoxicological characteristics of a proposed remediation technique have been identified, the process can be analyzed and the ex-situ or in-situ application mode can be defined, considering also the characteristics of the system to be remediated, whether it is wastewater, what type of flow predominates, laminar or turbulent, type of mixture, temperature (Margalef, 1983). It is worth mentioning that in Mexico, the Ministry of the Environment and Natural Resources (SEMARNAT) indicates that the control organisms to be used for these studies are Daphnia magna.\u003c/p\u003e\u003cp\u003eAmong the remediation techniques to remove metals are Aquatic Humic Substances (AHS), which are the main reservoir of organic carbon in limnological systems and several studies have shown that these compounds can react with halogens, pesticides, fertilizers, and metals to form compounds that modify the distribution, accessibility and even toxicity (Chen et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Liu et al. 201; Gonz\u0026aacute;lez-Guadarrama et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Gonz\u0026aacute;lez-Guadarrama \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eFrom the ecotoxicological point of view, to apply a remediation technique, it is necessary, in the case of chemical methods, to identify the chemical species formed, solubility, melting or decomposition temperature, as well as the possible interaction with living beings, to verify the feasibility of application (Wetzel, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). AHS are no exception, and it is necessary to determine the characteristics of humates and the effect they will have on the distribution of major and trace elements within water bodies (Davidge et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2001\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eTrace metals can be considered essential, essential-toxic or toxic depending on their concentration, chemical speciation and relationship with the metabolic processes of organisms (Crossgrove \u0026amp; Zheng, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Kumar, 2012). It is also important to study the reactivity of essential metals towards AHS, since their concentration is determinant for organisms (Rodwell, 2019).\u003c/p\u003e\u003cp\u003eIt is important to identify an adequate method to ensure that the concentration of toxic essential metals do not exceed the limits established by national and international drinking water standards. Among the metals that belong to this classification are Cu, Mn, Cr, Zn, Co, Fe, Mo, Mg, Ca, Na and K (Ali et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2019\u003c/span\u003e, NOM-127-SSA1-2021, ONU, Agua, 2023).\u003c/p\u003e\u003cp\u003eIt is necessary to study the compounds' characteristics and evaluate the method's pertinence to use this remediation method; therefore, the objectives of this work are to determine the solubility and melting or decomposition temperature of copper, manganese, lead, zinc, and polymetallic humates, and to determine their stability under environmental conditions. In addition to elucidating the effects of AHS on the distribution of major elements (cationic) and trace elements within a water body, using as test organisms D magna.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003eThe experimental part is divided into three parts, the first consists of the formation and isolation of the humates with each metal (Cu, MN, Pb and Zn), and the second corresponds to the determination of solubility in distilled water at neutral, acidic (\u0026lt;\u0026thinsp;4) and basic (\u0026gt;\u0026thinsp;7) pH, in addition to the determination of melting or decomposition temperatures of the compounds using Fischer-Jhons equipment.\u003c/p\u003e\u003cp\u003eThe third part is focused on the analysis of the interaction between the major (cations) and trace elements with AHS, and the possible effects on their distribution within the water bodies, D. magna were used as test organisms. These organisms were selected according their life span and reproduction, the species has been indicated for environmental tests. In this specific case, D. magna was only included to identify the effect of the formation of metallic humates on metal bioavailability. For the development of this part, it was necessary to acquire the organisms and allow them to acclimatize to the environmental conditions and synthetic water for the experiments. To later use the organisms for the different systems in the same development conditions.\u003c/p\u003e\u003cp\u003eTo prepare the synthetic water with the necessary nutrients for the optimal development of Daphnia, NaHCO\u003csub\u003e3\u003c/sub\u003e (Sigma), CaCl\u003csub\u003e2\u0026middot;\u003c/sub\u003e2H\u003csub\u003e2\u003c/sub\u003eO (Meyer), MgSO\u003csub\u003e4\u003c/sub\u003e\u0026middot;2H\u003csub\u003e2\u003c/sub\u003eO (Merck), and KCl (Aldrich) were added, as recommended by Huam\u0026aacute;n-Tenorio (2017), spinach juice was also added, which represents a rich source of chlorophylls, a food indicated for microcrustaceans, as proposed by previous studies (N\u0026uacute;\u0026ntilde;ez and Hurtado 2005; Tan and Wang 2014). It is essential to note that all experiments were conducted in triplicate.\u003c/p\u003e\u003cp\u003eThe water used for the experiments was collected from the spring present in San Bartolo Morelos, State of Mexico, at coordinates 19\u0026deg;47'13'' N and 99\u0026deg;40'04'' W, the water sample was conditioned as previously indicated with the nutrients required for the experiments, to inoculate and cultivate the D. magna, and allow for their adaptation. Once the organisms were adapted, the experiment was continued as follows.\u003c/p\u003e\u003cp\u003eThree systems were set up to compare the availability of metals in the presence or absence of AHS and a control system to monitor the organisms: 1) System 1 or control, in which only the necessary nutrients were added. 2) System 2, containing the nutrients and heavy metals (Cu, Mn, Zn and Pb from a solution with a concentration of 500 mgL-1 for each element). 3) System 3 in which the AHS solution (100 mgL-1) and the solution of the metallic mixture described in system 2 were added.\u003c/p\u003e\u003cp\u003eAccording to the life span of the organisms, the duration of the experiment was 10 days. For the experiment, 50 adult organisms were placed in each system. Initial water samples were taken to verify the initial concentrations of major (cations) and trace elements. For the analysis of the organisms and their access to metals, after 10 days, 20 organisms were isolated from each of the systems and dried at room temperature, then digested with concentrated nitric acid for two hours and gauged to 25 mL with deionized water, and stored for later analysis.\u003c/p\u003e\u003cp\u003eAll concentrations were determined by ICP-OES (Inductively Coupled Plasma Atomic Emission Spectroscopy). These analyses were carried out with the Perkin-Elmer Optima 8300 DV equipment with S10 Perkin-Elmer Atomic Spectroscopy autosampler at the Atomic Spectroscopy Laboratory of the Institute of Geology of UNAM.\u003c/p\u003e\u003cp\u003eThe analytical conditions for each element are: Limit of Quantification (LQ) for Ca (0.072 mg L-1), Cu (0.033 mg L-1), K (0.446 mg L-1), Mg (0.030 mg L-1), Mn (0.001 mg L-1), Na (0. 188 mg L-1) and Zn (0.004 mg L-1) with uncertainty values for Ca (4.08%), Cu (1.88%), K (3.69%), Mg (4.01%), Mn (4.44%), Na (3.38%) and Zn (4. 01%).\u003c/p\u003e\u003cp\u003eThe mean and standard deviation values of the results were calculated using an Excel spreadsheet, as well as to determine the reproducibility, uncertainty, and error.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe solubility determined for all the coordination compounds between metals and AHS in deionized water is around 10\u003csup\u003e\u0026minus;\u0026thinsp;8\u003c/sup\u003e g L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, as can be seen in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Meanwhile, the results of the solubility tests with pH variation indicate that in an acid medium (pH\u0026thinsp;\u0026lt;\u0026thinsp;4.0) the compounds are soluble, and in an alkaline medium (pH\u0026thinsp;\u0026gt;\u0026thinsp;7.0) the compounds are insoluble).\u003c/p\u003e\u003cp\u003eIt was found that the coordination compounds do not melt but show decomposition temperature, which for all the compounds is higher than 573.15 K\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\u003eSolubility results for each of the compounds formed in deionized water\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCompound\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSolubility in deionized water\u003c/p\u003e\u003cp\u003e(g L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAHS-Cu\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3.85X10\u003csup\u003e\u0026minus;\u0026thinsp;8\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAHS-Mn\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.92X10\u003csup\u003e\u0026minus;\u0026thinsp;8\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAHS-Pb\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.81X10\u003csup\u003e\u0026minus;\u0026thinsp;7\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAHS-Zn\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.44X10\u003csup\u003e\u0026minus;\u0026thinsp;8\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAHS-Cu-Mn-Pb-Zn\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3.76X10\u003csup\u003e\u0026minus;\u0026thinsp;8\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe concentration values for the metals in solution at the beginning and at the end of the experiments obtained by ICP-OES analysis can be seen in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eConcentrations of major and trace elements in water for the three systems analyzed at the beginning of the experiment.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\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=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIon/System\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSystem 1(mgL\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSystem 2(mgL\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSystem 3(mgL\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNa\u003csup\u003e+\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e74.59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e74.59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e74.59\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eK\u003csup\u003e+\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e33.99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e33.99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e33.99\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCa\u003csup\u003e2+\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e51.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e51.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e51.57\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMg\u003csup\u003e2+\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e36.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e36.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e36.55\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCu\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;LD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.414\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.414\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMn\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.105\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.561\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.561\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePb\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;LD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.403\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.403\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eZn\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.008\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.579\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.576\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eLD\u0026thinsp;=\u0026thinsp;Detection limit\u003c/p\u003e\u003cp\u003eThe concentration of major and trace elements of the D. magna from the three systems post-experiment can be seen in Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. These figures show how the presence of AHS changes the interaction between organisms with major and trace elements.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe use of spinach juice may represent the cause of the slight enrichment of Mn, while the organisms contain Cu and Pb naturally as observed in the control.\u003c/p\u003e\u003cp\u003eThe final concentration of the elements in the three systems can be seen in the Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eConcentrations of the metals in solution at the end of the experiment. System 1: control (nutrients only), System 2: nutrients and heavy metals, System 3: nutrients, heavy metals and AHS solution\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIon/System\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSystem 1\u003c/p\u003e\u003cp\u003e(mgL\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSystem 2\u003c/p\u003e\u003cp\u003e(mgL\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSystem 3\u003c/p\u003e\u003cp\u003e(mgL\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNa\u003csup\u003e+\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e66.79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e65.129\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e67.78\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eK\u003csup\u003e+\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e33.99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e31.21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e29.57\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCa\u003csup\u003e2+\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e51.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e61.03\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e45.36\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMg\u003csup\u003e2+\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e36.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e32.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e31.08\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCu\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;LD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u0026lt;LD\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.046\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMn\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.085\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.345\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.049\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePb\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;LD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u0026lt;LD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026lt;LD\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eZn\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.008\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.236\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.076\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe solubility results show that the compounds are insoluble in alkaline and neutral media, so under normal water body conditions and considering the pH established by the standards for drinking water and water bodies between 6 and 9 (NOM-127-SSA1-2021 and NOM-001-SEMARNAT-2021) they would precipitate, which means that the metals would be eliminated or their concentration in the water column would be reduced. However, physical factors such as turbulent flow or waves can resuspend the compounds and make the metals bioaccessible. While at acidic pH the compounds formed are completely soluble, which means that if an event such as an acid spill or acidification of the water bodies occurs, the compounds would be soluble, which would allow the metals to be reincorporated into the water column.\u003c/p\u003e\u003cp\u003eAnother factor to consider regarding the low solubility is that other pollutants could co-precipitate in water bodies, which would be beneficial for water treatment, nevertheless also nutrients, which would not be adequate for organisms.\u003c/p\u003e\u003cp\u003eAs for the decomposition temperature of the compounds, it can be highlighted that, being so high, they suggest high stability in environmental conditions, so AHS can be an effective method to reduce or eliminate metal contamination in natural environments or in wastewater.\u003c/p\u003e\u003cp\u003eAs can be observed and according to the studies previously reported by Gonz\u0026aacute;lez-Guadarrama et al. (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) a considerable decrease in metal concentration in the water to the initial value of each system occurred, thus the heavy metals lessen more than 90% for Cu, Mn and Pb, while for Zn it is reduced by about 85%. This decrease in concentrations of metals shows that AHS have the capacity to react with all metals, so they are an excellent alternative for treating water polluted with metals, since the removal is multi-elemental, as can be seen by comparing the concentrations reported in Tables\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eAn important contribution to the presence of manganese in all systems is spinach juice, since it was detected in the control system samples while it was absent in the natural samples without conditioning.\u003c/p\u003e\u003cp\u003eThe reaction products between AHS and major or trace elements in natural waters provide relevant information on the behavior of metals. Previous studies (Liu et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2010\u003c/span\u003e) indicate that major elements can react with AHS and reduce their bioavailability. However, what we observed here, is that the presence of AHS affects in different ways the availability of cations since Na concentration increased in system 3, possibly due to its natural presence in the AHS and/or the isolation process (Thurman and Malcom, 1981) that uses a NaOH solution.\u003c/p\u003e\u003cp\u003eThe results obtained with the test organisms indicate, according to Figs.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and 3, that the presence of AHS and metals modifies the intake capacity. Daphnia reduces potassium intake by almost 90% in the presence of metals and metals with AHS, compared to the control system, and in the case of magnesium by almost 50% in the presence of metals and 40% in the presence of metals and AHS, also compared to the control system.\u003c/p\u003e\u003cp\u003eIn the case of Ca, an inverse situation is observed, with a 52% increase in intake in the presence of metals and 40% in the presence of trace metals and AHS, which may be a reflection of the contribution of the AHS themselves and the characteristics of the exoskeleton. In the case of sodium, the behavior depends on the other species present; when only other metals are present, its intake decreases by up to 30% and when AHS are also present, it decreases by 5%, as can be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eIt can be said that the presence of AHS affects the assimilation of nutrients as indicated by Kazmierczak et al. (2011), also the availability of nutrients, as well as trace metals, which would be reflected in the development and life cycle of organisms, in this case the D. Magna.\u003c/p\u003e\u003cp\u003eThe results obtained indicate that AHS in water bodies may represent a conflict, because they not only decrease the concentrations of heavy metals, but also modify the interaction between organisms and heavy metals, but also with nutrients, which can be seen in Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, such modifications could be reflected in damage to the organisms limiting their access to the ideal concentrations to carry out metabolic processes These effects and interactions constrain the application of AHS directly in water bodies as a remediation technique.\u003c/p\u003e\u003cp\u003eAccording to Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, it is observed that the D. magna do not have elevated concentrations of heavy metals, but AHS modify the uptake of metals by organisms both in terms of nutrients and trace elements present in water bodies, so its use as a remediation technique should be restricted to pretreatment or to an ex-situ method.\u003c/p\u003e\u003cp\u003eThe described experimental results suggest that the use of AHS is an effective method to remove metals from wastewater as an ex-situ treatment, since within the water bodies they can react with nutrients and modify their bioavailability. Situation that could explain the trophic status of polyhumic lakes in Poland, which despite having high concentrations of AHS as their name suggests are oligotrophic, corresponding to low nutrient concentration and low presence of organisms (Kazmierczak et al., 2011; Ejankowski and Iglinska, 2014; Du Preez and Wepener, 2016). AHS can then be considered to avoid the dispersion of heavy metals into the environment at sites such as mine tailings or in the elimination or decrease within the water column at wastewater discharge sites and would greatly improve water quality and its return to the environment.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eAHS are an excellent alternative for removing metals from wastewater, so using them as a remediation technique is a great option, as they are used as a pretreatment prior to discharge into natural water bodies.\u003c/p\u003e\u003cp\u003eThe compounds formed under ambient conditions are stable, according to their decomposition temperature and solubility pH, which is low (\u0026le;\u0026thinsp;4) and is not recommended for use in drinking water or wastewater according to the standards.\u003c/p\u003e\u003cp\u003eThe reactions are favored and the products precipitate due to their low solubility, which could cause them to co-precipitate other compounds present in the wastewater.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cem\u003eThis work was supported by scholarship. Grant number 71/2020 Author Mar\u0026iacute;a de Jes\u0026uacute;s Gonz\u0026aacute;lez Guadarrama has received research support from DGAPA, UNAM\u003c/em\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003cp\u003e\u003cem\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/em\u003e\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor contributions\u003c/h2\u003e\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Mar\u0026iacute;a de Jes\u0026uacute;s Gonz\u0026aacute;lez Guadarrama. The first draft of the manuscript was written by Mar\u0026iacute;a de Jes\u0026uacute;s Gonz\u0026aacute;lez Guadarrama and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e\u003cp\u003eI thank the Postdoctoral Fellowship Program of the DGAPA of UNAM. The technical support of Javier Tadeo M. Sc., Patricia Fierro Biol., Karla Patricia Salas Martin Dr., Olivia Cruz Ronquillo QFB, Alejandra Aguayo R\u0026iacute;os M. Ing., and Omar Neri Hern\u0026aacute;ndez QFB.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAli H, Khan E. (2019) Trophic transfer, bioaccumulation and biomagnification of non-essential hazardous heavy metals and metalloids in food chains/webs-concepts and implications for wildlife and human health. Human and Ecological risk. Assessment 25:6, 1353-1376. https://doi.org/10.1080/10807039.2018.1469398\u003c/li\u003e\n\u003cli\u003eAli, H., Khan, E., \u0026amp; Ilahi, I. (2019). Environmental chemistry and ecotoxicology of hazardous heavy metals: environmental persistence, toxicity, and bioaccumulation. \u003cem\u003eJournal of chemistry\u003c/em\u003e, \u003cem\u003e2019\u003c/em\u003e(1), 6730305. https://doi.org/10.1155/2019/6730305\u003c/li\u003e\n\u003cli\u003eChen C., Wang X., Jiang H., Hu W., (2007) Direct observation of macromolecular structures of humic acid by AFM and SEM\u003cstrong\u003e.\u003c/strong\u003e Colloids and surface A: Physicochem. Eng. Aspects, 302; 121-125. https://doi.org/10.1016/j.colsurfa.2007.02.014\u003c/li\u003e\n\u003cli\u003eChouvelon T, Strady E, Harmelin-Vivien M, Radakovith O, Brach-Pap C, Crochet S, Knoery J, Rozuel E, Thomas B, Tronezynski J, Chiffdeau H, (2019) Patterns of trace metals bioaccumulation and trophic transfer in a phytoplankton-zooplankton-small pelagic fish marine food web. Marine Pollution Bulletin. 146;1013-1030. https://doi.org/10.1016/j.marpolbul.2019.07.047\u003c/li\u003e\n\u003cli\u003eCrossgrove J., Zheng W. (2004) Manganese toxicity upon overexposure. NMR IN BIOMEDICINE, 17, 8; 544-553. https://doi.org/10.1002/nbm.931\u003c/li\u003e\n\u003cli\u003eDavidge J., Thomas C. P. Williams D. R. (2001) Conditional formation constants or chemical speciation data?Chemical speciation and Bioavailability, 13, 4; 129-134. https://doi.org/10.3184/095422901782775390\u003c/li\u003e\n\u003cli\u003eDe Forest D.K. Brix K.V. Adams W.J. (2007) Assessing metal bioaccumulation in aquatic environments: The inverse relationship between bioaccumulation factors, trophic transfer factors and exposure concentration, Aquatic Toxicology, 84, 236-246. https://doi.org/10.1016/j.aquatox.2007.02.022\u003c/li\u003e\n\u003cli\u003eDe Shamphelaere KC., Janssen CR (2004) Effects of Dissolved Organic Carbon Concentration and Source, pH, and water hardness on chronic toxicity of copper to Daphnia Magna. Environ Toxicol and Chem, 23;5,1115-1122. https://doi.org/10.1897/02-593.\u003c/li\u003e\n\u003cli\u003eFang T, Lu W, Cui K, Li J, Yang K, Zhao X, Liang Y, Li H., (2019), Distribution, bioaccumulation and trophic transfer of trace metals in the food web of Chaohu Lake, Anhui, China, Chemosphere, 218, 1122-1130. https://doi.org/10.1016/j.chemosphere.2018.10.107\u003c/li\u003e\n\u003cli\u003eGandara, M., Galdino, R. L., \u0026amp; Caraballo, P. (2013). Historia de vida de Daphnia magna y Ceriodaphnia reticulata en condiciones de laboratorio: uso potencial como alimento para peces. \u003cem\u003eRevista Colombiana de Ciencia Animal\u003c/em\u003e, \u003cem\u003e5\u003c/em\u003e(2), 340-357. https://doi.org/10.24188/recia.v5.n2.2013.447\u003c/li\u003e\n\u003cli\u003eGonz\u0026aacute;lez-Guadarrama MJ. (2018) Interacci\u0026oacute;n de Sustancias H\u0026uacute;micas Acu\u0026aacute;ticas con As, Cu, Mn y Zn. (Tesis doctoral) Universidad Nacional Aut\u0026oacute;noma de M\u0026eacute;xico.\u003c/li\u003e\n\u003cli\u003eGonz\u0026aacute;lez-Guadarrama MJ, Armienta-Hern\u0026aacute;ndez MA, Rosa A H (2018), Aquatic Humic Substances: Relationship Between Origin and Complexing Capacity. \u003cem\u003eBull Environ Contam Toxicol\u003c/em\u003e 100, 627\u0026ndash;633. DOI 10.1007/s00128-018-2318-4\u003c/li\u003e\n\u003cli\u003eGoulet RR., Krack S, Doyle PJ., Have, L, Vigneault B, McGeer JC, (2007) Dynamic multipathway modelling of Cd bioaccumulation in Daphnia magna using waterborne and diet borne exposures. Aquatic Toxicology, 81; 117-125. https://doi.org/10.1016/j.aquatox.2006.11.008.\u003c/li\u003e\n\u003cli\u003eHuam\u0026aacute;n Tenorio, V. (2017). Crecimiento poblacional de Daphnia magna \u0026ldquo;pulga de agua\u0026rdquo; en cultivo experimental alimentado con Saccharomyces cerevisiae \u0026ldquo;levadura\u0026rdquo; y jugo de Spinacia oleracea \u0026ldquo;espinaca\u0026rdquo;. (Tesis de Licenciatura) http://repositorio.unsch.edu.pe/handle/UNSCH/1657\u003c/li\u003e\n\u003cli\u003eKumar G. V., Nayak A., Agarwal S., Dobhal R., Prasada. D., Singh P., Sharma B., Tyagi S., Singh R. (2012) Arsenic speciation analysis and remediation techniques in drinking water. Taylor \u0026amp;Francois, 40;231-243. https://doi.org/10.1016/S1001-0742(09)60308-9\u003c/li\u003e\n\u003cli\u003eLiu J., Wang J., Chen Y., Lippold H., Lippman-Pipke J. (2010) Comparative characterisation of two natural humic acids in the Pearl River Basin, China and their environmental implications\u003cstrong\u003e. \u003c/strong\u003eJ. of Environmental Sciences, 22, 11; 1695-1702. https://doi.org/10.1016/S1001-0742(09)60308-9\u003c/li\u003e\n\u003cli\u003ePriti, P., \u0026amp; Paul, B. (2016). Assessment of heavy metal pollution in water resources and their impacts: A review. \u003cem\u003eJournal of Basic and Applied Engineering Research\u003c/em\u003e, \u003cem\u003e3\u003c/em\u003e(8), 671-675.\u003c/li\u003e\n\u003cli\u003eThurman, E. M., \u0026amp; Malcolm, R. L. (1981). Preparative isolation of aquatic humic substances. \u003cem\u003eEnvironmental science \u0026amp; technology\u003c/em\u003e, \u003cem\u003e15\u003c/em\u003e(4), 463-466.\u003c/li\u003e\n\u003cli\u003eVerma, R., \u0026amp; Dwivedi, P. (2013). Heavy metal water pollution-A case study. \u003cem\u003eRecent research in Science and Technology\u003c/em\u003e, \u003cem\u003e5\u003c/em\u003e(5).\u003c/li\u003e\n\u003cli\u003eWang, Z., Luo, P., Zha, X., Xu, C., Kang, S., Zhou, M., ... \u0026amp; Wang, Y. (2022). Overview assessment of risk evaluation and treatment technologies for heavy metal pollution of water and soil. \u003cem\u003eJournal of Cleaner Production\u003c/em\u003e, \u003cem\u003e379\u003c/em\u003e, 134043.https://doi.org/10.1016/j.jclepro.2022.134043.\u003c/li\u003e\n\u003cli\u003eWetzel, R.G. (2001) Limnology. Lake and River Ecosystems. 3a ed. Ed Elsevier. We USA.\u003c/li\u003e\n\u003c/ol\u003e"}],"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":"Aquatic humic substances, aquatic systems, heavy metals, nutrients, remediation techniques","lastPublishedDoi":"10.21203/rs.3.rs-7031857/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7031857/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this work, we studied the potential effects of aquatic humic substances on the water concentrations of major and trace elements in aquatic systems to evaluate their possible use as an alternative to heavy metals\u0026rsquo; pollution. Daphnia magna was used as a control for the test organisms. Aquatic humic substances are the first reservoir of carbon in freshwater bodies. To assess their potential as a remediation technique through complex formation, their physicochemical properties must be evaluated as a first step. This study was carried out to characterise the AHS compounds formed with Cu, Mn, Pb and Zn, corroborate their stability under natural conditions, and evaluate their potential for in situ or ex situ removal of heavy metals from aquatic systems. The results indicate that the studied metal humates (Cu, Mn, Pb and Zn) are soluble at an acidic pH (\u0026lt;\u0026thinsp;4) and insoluble at a neutral or alkaline pH. The decomposition temperature for all compounds (metal humates) exceeds 573.15 K, indicating that they are stable under normal environmental conditions. It was also identified that aquatic humic substances radically decrease the access of heavy metals to organisms, and, modify the concentrations of nutrients in the water which can impact the development of organisms, making direct application unviable. The technique can be applied to wastewater before it is discharged into water bodies. Results indicate that: the coordination compounds (metal humates) formed are stable in environmental conditions and this technique can be applied as a pretreatment or ex situ remediation process.\u003c/p\u003e","manuscriptTitle":"Evaluation of the application of Aquatic Humic Substances as a remediation technique for the removal of metals from water bodies","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-07 21:27:49","doi":"10.21203/rs.3.rs-7031857/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":"8f5ba365-1d0c-4c43-8904-c7f16936b0dc","owner":[],"postedDate":"July 7th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-10-04T18:21:46+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-07 21:27:49","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7031857","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7031857","identity":"rs-7031857","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}