Comprehensive Spatiotemporal Water Quality Assessment in Industrially Polluted Digaru River of Assam, India: Multivariate Statistics, Water Quality Indexing, and Human Health Risks

Comprehensive Spatiotemporal Water Quality Assessment in Industrially Polluted Digaru River of Assam, India: Multivariate Statistics, Water Quality Indexing, and Human Health Risks | 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 Comprehensive Spatiotemporal Water Quality Assessment in Industrially Polluted Digaru River of Assam, India: Multivariate Statistics, Water Quality Indexing, and Human Health Risks K Zamminsion, Jasraj Kumawat, Siddhant Dash, Ajay S. Kalamdhad This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9564326/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 11 You are reading this latest preprint version Abstract Environmental contamination from poor industrial and sewage management causes river pollution, a major global issue. The current study, on the Digaru River in India, a tributary of the Brahmaputra River passing through the polluted Byrnihat Industrial Clusters (BIC), analyses physicochemical water quality, including heavy metals, through monthly monitoring; identifies pollution sources and correlations using multivariate statistics; employs a novel Modified Entropy-Weighted Water Quality Index (MEWQI); and assesses human health risks. Based on 144 samples collected over a year, the study highlighted strong spatiotemporal variability and limited self-replenishment; monsoon months showed significantly elevated pollutants, including turbidity (> 500 NTU, mean:56 ± 104), BOD₅ (47 mg/L), COD (290 mg/L, mean:111 ± 85), and NO₃ − (56 mg/L, mean:07 ± 10). Among metals, Al (81%), Mn (69%), Fe (97%) and Pb (20%) exceeded safe limits, while Cr, Ni, Co, Zn, and Pb were regularly detected. The MEWQI reveals 45% of water quality classes are 'Extremely Poor', with 93.75% unsuitable for consumption. PCA bi-plots and HCA show complex seasonal groupings of physicochemical parameters and stations, indicating water quality decline due to sewage and industrial effluents from BIC and nearby zones. Non-carcinogenic risk assessments highlight higher CDI, HQ, and HI in children, driven by metals like Fe, Mn, and Cr. Furthermore, Incremental Carcinogenic Lifetime Risk (ICLR) values estimated for Cr (51 × 10⁻⁶) and Pb (95 × 10⁻⁸) indicate potential carcinogenic hazards to the exposed population. Collectively, the study offers vital insights into spatiotemporal pollution dynamics, providing a scientific basis for targeted water quality control and remediation strategies. Heavy Metals Industrial Pollution Multivariate Statistics Spatiotemporal Monitoring Risk Assessment Water Quality Indices Full Text Additional Declarations No competing interests reported. Supplementary Files Supplementary.docx Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 14 May, 2026 Reviews received at journal 14 May, 2026 Reviews received at journal 06 May, 2026 Reviewers agreed at journal 05 May, 2026 Reviewers agreed at journal 04 May, 2026 Reviewers agreed at journal 01 May, 2026 Reviewers agreed at journal 30 Apr, 2026 Reviewers invited by journal 30 Apr, 2026 Editor assigned by journal 30 Apr, 2026 Submission checks completed at journal 30 Apr, 2026 First submitted to journal 29 Apr, 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-9564326","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":635220305,"identity":"7b43d280-e279-4030-9f4e-03ba4b6ef4cb","order_by":0,"name":"K Zamminsion","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA60lEQVRIiWNgGAWjYBACCTjFDKQ+GED5DAZEamGcYSAhQawWCGDmQRPACiQb2B9+upljkSffznzssU2BRZ28A/PDDwwFd3BqkWZgSJbO3SZRbHCYLd04B+gwwwNsxhIMBs9wapFjYDgA0pK4gZnHTBqspYHBDOiXw3i0MDb/BmmZ3wzUYgHWwv4NrxZpBmY2sC0Nh4FaGIBa5Bl48Nsi2czGZg122GG2NMkeAwlJoAuLJRLwaJE43v74du62usT5/YePSfz4U8cv396+8cOHP7i1gCMdBYDNT8CtAQuQbyBJ+SgYBaNgFIwAAACSDkMa87hpygAAAABJRU5ErkJggg==","orcid":"","institution":"Indian Institute of Technology Guwahati","correspondingAuthor":true,"prefix":"","firstName":"K","middleName":"","lastName":"Zamminsion","suffix":""},{"id":635220316,"identity":"2ae96982-ca90-42d6-b040-dcc048a6f635","order_by":1,"name":"Jasraj Kumawat","email":"","orcid":"","institution":"Indian Institute of Science","correspondingAuthor":false,"prefix":"","firstName":"Jasraj","middleName":"","lastName":"Kumawat","suffix":""},{"id":635220320,"identity":"d5a981f6-c58b-43ef-ae4c-8dece1402903","order_by":2,"name":"Siddhant Dash","email":"","orcid":"","institution":"SRM University","correspondingAuthor":false,"prefix":"","firstName":"Siddhant","middleName":"","lastName":"Dash","suffix":""},{"id":635220324,"identity":"f54e5f70-75eb-443a-8dfd-293aa7c8dc1d","order_by":3,"name":"Ajay S. 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The current study, on the Digaru River in India, a tributary of the Brahmaputra River passing through the polluted Byrnihat Industrial Clusters (BIC), analyses physicochemical water quality, including heavy metals, through monthly monitoring; identifies pollution sources and correlations using multivariate statistics; employs a novel Modified Entropy-Weighted Water Quality Index (MEWQI); and assesses human health risks. Based on 144 samples collected over a year, the study highlighted strong spatiotemporal variability and limited self-replenishment; monsoon months showed significantly elevated pollutants, including turbidity (\u0026gt;\u0026thinsp;500 NTU, mean:56\u0026thinsp;\u0026plusmn;\u0026thinsp;104), BOD₅ (47 mg/L), COD (290 mg/L, mean:111\u0026thinsp;\u0026plusmn;\u0026thinsp;85), and NO₃\u003csup\u003e\u0026minus;\u003c/sup\u003e (56 mg/L, mean:07\u0026thinsp;\u0026plusmn;\u0026thinsp;10). Among metals, Al (81%), Mn (69%), Fe (97%) and Pb (20%) exceeded safe limits, while Cr, Ni, Co, Zn, and Pb were regularly detected. The MEWQI reveals 45% of water quality classes are 'Extremely Poor', with 93.75% unsuitable for consumption. PCA bi-plots and HCA show complex seasonal groupings of physicochemical parameters and stations, indicating water quality decline due to sewage and industrial effluents from BIC and nearby zones. Non-carcinogenic risk assessments highlight higher CDI, HQ, and HI in children, driven by metals like Fe, Mn, and Cr. Furthermore, Incremental Carcinogenic Lifetime Risk (ICLR) values estimated for Cr (51 \u0026times; 10⁻⁶) and Pb (95 \u0026times; 10⁻⁸) indicate potential carcinogenic hazards to the exposed population. 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