Rare Earth Elements as Emerging Contaminants in the Surface Sediments of Maroon-Jarahi Sub-basin (Persian Gulf Coasts): Assessment of Pollution, Distribution, and Potential Ecological-Health Risk ‏

Rare Earth Elements as Emerging Contaminants in the Surface Sediments of Maroon-Jarahi Sub-basin (Persian Gulf Coasts): Assessment of Pollution, Distribution, and Potential Ecological-Health Risk ‏ | 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 Rare Earth Elements as Emerging Contaminants in the Surface Sediments of Maroon-Jarahi Sub-basin (Persian Gulf Coasts): Assessment of Pollution, Distribution, and Potential Ecological-Health Risk ‏ Fariba Hedayatzadeh, Alireza Ildoromi, Nasrin Hassanzadeh, Nader Bahramifar, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7275711/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 08 Oct, 2025 Read the published version in Environmental Geochemistry and Health → Version 1 posted 8 You are reading this latest preprint version Abstract Rare earth elements (REEs) have garnered increasing attention as emerging micropollutants in aquatic environments. Nevertheless, our knowledge of the pollution, environmental consequences, and hazards resulting from the presence of REEs in aquatic sediments is limited. This research aims to quantify and explain the distribution patterns, identify the sources, determine the pollution levels, and assess the potential environmental and health risks of rare earth elements in the sediments of the Maroon-Jarahi sub-basin (ending in the Persian Gulf). Surface sediment sampling was conducted at 70 stations at the outlet points of the sub-basins. Quantitative analysis of the REEs was performed using inductively coupled plasma mass spectrometry (ICP-MS). To evaluate the pollution levels and potential impacts, the geo-accumulation index (I-geo) and enrichment factor (EF) were used, along with ecological and health risk assessment models. The results showed that the concentration of ΣREEs in the surface sediments of the Maroon-Jarahi sub-basin varies from 100.79 to 231.81 mg/kg, and for sub-basins, the Jarahi River in the downstream area also had the highest concentration of LREE, MREE, and HREE. Based on the I-geo index, pollution by Nd, Sm, and Gd was assessed as moderate, whereas the other elements showed no pollution. The analysis of the EF factor also indicated the enrichment of LREEs relative to HREEs, with the highest enrichment observed for the elements Nd, Sm, and Gd. The ecological risk assessment of REEs indicated low ecological risk, with variable values ranging from 21.23 to 112.27, That the largest contribution to the potential ecological risk was related to Lu (17%), followed by Eu (12%), and Gd = Tb = Tm (9%). The analysis of non-carcinogenic health effects based on HQ values also indicated that REEs in the surface sediments of the area have negligible adverse effects on human health. The carcinogenic health risk assessment also showed that the average ILCRs for adults and children are 9.91 × 10 − 16 and 6.89 × 10 − 15 , respectively. The findings of this research indicate the impact of anthropogenic activities on pollution levels and ecological risk associated with some REEs in the sediments of the Maroon-Jarahi sub-basin. Therefore, continuous monitoring and the implementation of targeted management measures to control the release of REEs are essential to protect ecological integrity and reduce the potential risks resulting from their accumulation for the health of local communities. Emerging micro-pollutants Rare earth elements Sediments Potential risks Sub-watershed scale Persian Gulf Full Text Additional Declarations No competing interests reported. Supplementary Files Highlights1.docx GraphicalAbstract2.pdf Cite Share Download PDF Status: Published Journal Publication published 08 Oct, 2025 Read the published version in Environmental Geochemistry and Health → Version 1 posted Editorial decision: Revision requested 28 Aug, 2025 Reviews received at journal 23 Aug, 2025 Reviewers agreed at journal 03 Aug, 2025 Reviewers agreed at journal 02 Aug, 2025 Reviewers invited by journal 02 Aug, 2025 Editor assigned by journal 02 Aug, 2025 Submission checks completed at journal 02 Aug, 2025 First submitted to journal 02 Aug, 2025 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. 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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-7275711","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":494817147,"identity":"ffba38ea-646f-460b-a91a-76a8182430b6","order_by":0,"name":"Fariba Hedayatzadeh","email":"","orcid":"","institution":"Malayer University","correspondingAuthor":false,"prefix":"","firstName":"Fariba","middleName":"","lastName":"Hedayatzadeh","suffix":""},{"id":494817148,"identity":"9550620a-0ba2-4ad8-8a5c-eb8ee77adf6e","order_by":1,"name":"Alireza Ildoromi","email":"","orcid":"","institution":"Malayer 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Nevertheless, our knowledge of the pollution, environmental consequences, and hazards resulting from the presence of REEs in aquatic sediments is limited. This research aims to quantify and explain the distribution patterns, identify the sources, determine the pollution levels, and assess the potential environmental and health risks of rare earth elements in the sediments of the Maroon-Jarahi sub-basin (ending in the Persian Gulf). Surface sediment sampling was conducted at 70 stations at the outlet points of the sub-basins. Quantitative analysis of the REEs was performed using inductively coupled plasma mass spectrometry (ICP-MS). To evaluate the pollution levels and potential impacts, the geo-accumulation index (I-geo) and enrichment factor (EF) were used, along with ecological and health risk assessment models. The results showed that the concentration of ΣREEs in the surface sediments of the Maroon-Jarahi sub-basin varies from 100.79 to 231.81 mg/kg, and for sub-basins, the Jarahi River in the downstream area also had the highest concentration of LREE, MREE, and HREE. Based on the I-geo index, pollution by Nd, Sm, and Gd was assessed as moderate, whereas the other elements showed no pollution. The analysis of the EF factor also indicated the enrichment of LREEs relative to HREEs, with the highest enrichment observed for the elements Nd, Sm, and Gd. The ecological risk assessment of REEs indicated low ecological risk, with variable values ranging from 21.23 to 112.27, That the largest contribution to the potential ecological risk was related to Lu (17%), followed by Eu (12%), and Gd\u0026thinsp;=\u0026thinsp;Tb\u0026thinsp;=\u0026thinsp;Tm (9%). The analysis of non-carcinogenic health effects based on HQ values also indicated that REEs in the surface sediments of the area have negligible adverse effects on human health. The carcinogenic health risk assessment also showed that the average ILCRs for adults and children are 9.91 \u0026times; 10\u003csup\u003e\u0026minus;\u0026thinsp;16\u003c/sup\u003e and 6.89 \u0026times; 10\u003csup\u003e\u0026minus;\u0026thinsp;15\u003c/sup\u003e, respectively. The findings of this research indicate the impact of anthropogenic activities on pollution levels and ecological risk associated with some REEs in the sediments of the Maroon-Jarahi sub-basin. 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