Geochemical controls on rare earth element and yttrium bioaccumulation in Unio elongatulus from contrasting subalpine lakes

Geochemical controls on rare earth element and yttrium bioaccumulation in Unio elongatulus from contrasting subalpine lakes | 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 Geochemical controls on rare earth element and yttrium bioaccumulation in Unio elongatulus from contrasting subalpine lakes Maria Chiara Fontanella, Irene Geneselli, Nicoletta Riccardi, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9214384/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 9 You are reading this latest preprint version Abstract Rare earth elements and yttrium (REY) are increasingly recognized as elements of emerging environmental interest in aquatic ecosystems, yet the factors governing their accumulation in freshwater organisms remain poorly constrained. Here, we investigated REY bioaccumulation and fractionation in soft tissues and shells of the freshwater mussel Unio elongatulus from two subalpine Italian lakes with contrasting geochemical settings. REY concentrations were determined by ICP–MS/MS and normalized to European Shale in order to distinguish natural geogenic signatures from potential anthropogenic inputs. Soft tissues accumulated up to 28-fold higher ΣREY than shells, reflecting short-term versus long-term integration, and were consistently enriched in light REE (67–79% of ΣREY). Shale-normalized patterns showed [La/Yb] SN > 1 in both matrices, together with moderate positive La, Gd, and Eu anomalies and weak negative Ce anomalies. These features indicate that geogenic processes, including feldspar weathering and redox-controlled Ce behaviour, are the dominant drivers of REY bioavailability. Shells from Lake Maggiore displayed slightly higher ΣREY than those from Lake Orta, in agreement with greater sediment inputs and natural REY supply. Overall, U. elongatulus integrates ambient REY signatures across different biological compartments and shows potential as a biomonitor of geochemical gradients in freshwater ecosystems. Our findings indicate that REY accumulation in this species is primarily governed by natural geogenic factors rather than anthropogenic pollution, with implications for the environmental assessment of trace elements in freshwater environments. Rare earth elements and yttrium (REY) Unio elongatulus freshwater bivalves bioaccumulation environmental geochemistry geogenic control Full Text Additional Declarations No competing interests reported. Supplementary Files EGHREEUnioSUPPLEMENTARYMATERIALTABLE.docx EGHREEUnioSUPPLEMENTARYMATERIALTableS7softtissue.xlsx EGHREEUnioSUPPLEMENTARYMATERIALTableS8shell.xlsx EGHREEUnioSUPPLEMENTARYMATERIALFIGURE.doc Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 22 Apr, 2026 Reviews received at journal 02 Apr, 2026 Reviewers agreed at journal 31 Mar, 2026 Reviewers agreed at journal 31 Mar, 2026 Reviewers agreed at journal 30 Mar, 2026 Reviewers invited by journal 30 Mar, 2026 Editor assigned by journal 25 Mar, 2026 Submission checks completed at journal 25 Mar, 2026 First submitted to journal 24 Mar, 2026 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-9214384","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":615197975,"identity":"00814a52-1a49-4163-8d08-2481be21a442","order_by":0,"name":"Maria Chiara 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Here, we investigated REY bioaccumulation and fractionation in soft tissues and shells of the freshwater mussel Unio elongatulus from two subalpine Italian lakes with contrasting geochemical settings. REY concentrations were determined by ICP–MS/MS and normalized to European Shale in order to distinguish natural geogenic signatures from potential anthropogenic inputs.\u003c/p\u003e\n\u003cp\u003eSoft tissues accumulated up to 28-fold higher ΣREY than shells, reflecting short-term versus long-term integration, and were consistently enriched in light REE (67–79% of ΣREY). Shale-normalized patterns showed [La/Yb]\u003csub\u003eSN\u003c/sub\u003e \u0026gt; 1 in both matrices, together with moderate positive La, Gd, and Eu anomalies and weak negative Ce anomalies. These features indicate that geogenic processes, including feldspar weathering and redox-controlled Ce behaviour, are the dominant drivers of REY bioavailability. 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