Road construction effects on estuarine wetland soil organic carbon and heavy metals: evidence for near-road disturbance thresholds and buffer zoning

Road construction effects on estuarine wetland soil organic carbon and heavy metals: evidence for near-road disturbance thresholds and buffer zoning | 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 Road construction effects on estuarine wetland soil organic carbon and heavy metals: evidence for near-road disturbance thresholds and buffer zoning Xiaoying Lin, Xinchong Cao, Zhipeng Liu, Chunxue Li, Shuaiyu Wei, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8357958/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract While the impacts of road construction are well-known, quantitative data on SOC disturbance thresholds specifically for estuarine wetlands remain relatively limited. To provide evidence for this specific context, we analyzed the near-road disturbance in the Fujian Minjiang River Estuary Wetlands (Ramsar Site No. 2506, southeast China). We used 56 plots at 5–70 m from an expressway to examine soil responses to construction. Surface (0–10 cm) and selected profile (0–50 cm) soils were analyzed for soil organic carbon (SOC), bulk density (BD), moisture, pH, and heavy metals (Cr, Ni, Cu, Zn, Cd). Distance effects were tested using mixed-effects and segmented regression models, analysis of variance (ANOVA), and correlation analyses. Surface SOC increased significantly with distance from the road. When grouped into distance classes, mean SOC in the roadside zone (0–30 m) was about 12% lower than in the reference zone (> 50 m). Segmented regression further identified a SOC breakpoint at 29.9 m from the road (95% CI: 27.0–32.8 m), beyond which the SOC–distance relationship became much flatter (R² = 0.86). Near-road soils showed the highest BD and lowest moisture, while several metals were clearly enriched within 0–30 m. These patterns indicate that compaction, altered hydrological connectivity, and traffic-related pollution jointly redistribute wetland carbon. We recommend a three-zone buffer (0–30, 30–50, > 50 m) and ≥ 50 m road–wetland setbacks, expanded in high-risk settings, to better align expressway development with protection of estuarine wetland carbon sinks. Estuarine wetland Road construction Soil organic carbon Heavy metals Buffer zone Full Text Additional Declarations No competing interests reported. Supplementary Files SupplementaryInformation.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 25 Mar, 2026 Reviews received at journal 27 Dec, 2025 Reviewers agreed at journal 19 Dec, 2025 Reviewers agreed at journal 17 Dec, 2025 Reviewers invited by journal 17 Dec, 2025 Editor assigned by journal 16 Dec, 2025 Submission checks completed at journal 16 Dec, 2025 First submitted to journal 14 Dec, 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. We do this by developing innovative software and high quality services for the global research community. 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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-8357958","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":561653711,"identity":"64ffcfa5-0a1a-426b-848e-8436f55b263e","order_by":0,"name":"Xiaoying 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zoning","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"wetlands-ecology-and-management","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"wetl","sideBox":"Learn more about [Wetlands Ecology and Management](https://www.springer.com/journal/11273)","snPcode":"11273","submissionUrl":"https://submission.nature.com/new-submission/11273/3","title":"Wetlands Ecology and Management","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Estuarine wetland, Road construction, Soil organic carbon, Heavy metals, Buffer zone","lastPublishedDoi":"10.21203/rs.3.rs-8357958/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8357958/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWhile the impacts of road construction are well-known, quantitative data on SOC disturbance thresholds specifically for estuarine wetlands remain relatively limited. To provide evidence for this specific context, we analyzed the near-road disturbance in the Fujian Minjiang River Estuary Wetlands (Ramsar Site No. 2506, southeast China). We used 56 plots at 5\u0026ndash;70 m from an expressway to examine soil responses to construction. Surface (0\u0026ndash;10 cm) and selected profile (0\u0026ndash;50 cm) soils were analyzed for soil organic carbon (SOC), bulk density (BD), moisture, pH, and heavy metals (Cr, Ni, Cu, Zn, Cd). Distance effects were tested using mixed-effects and segmented regression models, analysis of variance (ANOVA), and correlation analyses. Surface SOC increased significantly with distance from the road. When grouped into distance classes, mean SOC in the roadside zone (0\u0026ndash;30 m) was about 12% lower than in the reference zone (\u0026gt;\u0026thinsp;50 m). Segmented regression further identified a SOC breakpoint at 29.9 m from the road (95% CI: 27.0\u0026ndash;32.8 m), beyond which the SOC\u0026ndash;distance relationship became much flatter (R\u0026sup2; = 0.86). Near-road soils showed the highest BD and lowest moisture, while several metals were clearly enriched within 0\u0026ndash;30 m. These patterns indicate that compaction, altered hydrological connectivity, and traffic-related pollution jointly redistribute wetland carbon. We recommend a three-zone buffer (0\u0026ndash;30, 30\u0026ndash;50, \u0026gt;\u0026thinsp;50 m) and \u0026ge;\u0026thinsp;50 m road\u0026ndash;wetland setbacks, expanded in high-risk settings, to better align expressway development with protection of estuarine wetland carbon sinks.\u003c/p\u003e","manuscriptTitle":"Road construction effects on estuarine wetland soil organic carbon and heavy metals: evidence for near-road disturbance thresholds and buffer zoning","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-19 05:15:17","doi":"10.21203/rs.3.rs-8357958/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"168465940092478471196876373276065840043","date":"2026-03-25T11:28:58+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-27T13:43:28+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"251110073408697666613194572648313911964","date":"2025-12-19T14:41:08+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"312172586142279229283220669672534322032","date":"2025-12-17T08:57:43+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-12-17T08:18:16+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-12-16T11:38:56+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-12-16T08:55:37+00:00","index":"","fulltext":""},{"type":"submitted","content":"Wetlands Ecology and Management","date":"2025-12-14T12:20:08+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"wetlands-ecology-and-management","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"wetl","sideBox":"Learn more about [Wetlands Ecology and Management](https://www.springer.com/journal/11273)","snPcode":"11273","submissionUrl":"https://submission.nature.com/new-submission/11273/3","title":"Wetlands Ecology and Management","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"6db413de-0643-4e7d-89d5-8ed4e95a710a","owner":[],"postedDate":"December 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-12-19T05:15:17+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-19 05:15:17","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8357958","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8357958","identity":"rs-8357958","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}