Integrated Physico-Chemical and Ecological Risk Assessment of Inland Wetlands in Tamil Nadu, India Reveals Nutrient-Driven Ecological Stress.
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| Title: | Integrated Physico-Chemical and Ecological Risk Assessment of Inland Wetlands in Tamil Nadu, India Reveals Nutrient-Driven Ecological Stress. |
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| Authors: | Arjunan, Praveen1 (AUTHOR), Kuppusamy, Saranya1,2 (AUTHOR), Sellappa, Kanmani1,2 (AUTHOR) skanmani@annauniv.edu |
| Source: | Water, Air & Soil Pollution. Aug2026, Vol. 237 Issue 15, p1-24. 24p. |
| Subject Terms: | *Nutrient pollution of water, *Wetland management, *Chemical testing, *Multivariate analysis, *Environmental risk, *Wetlands, *Organic wastes |
| Geographic Terms: | Tamil Nadu (India), India |
| Abstract: | This study evaluated ten inland wetlands in Tamil Nadu, India during May–July 2025 using a depth-integrated, multi-matrix (water–sediment-soil) assessment framework combining physico-chemical characterization, ecological risk indices and multivariate statistical modelling to identify dominant pollution stressors and inform sustainable wetland management. Water, sediment and soil samples were analysed following APHA (2017) standard methods. The integrated framework incorporated contamination factor, pollution load index, potential ecological risk index, geo-accumulation index, contamination degree, Pearson correlation, Kaiser–Meyer–Olkin test, Bartlett's test of sphericity and Principal Component Analysis (PCA) to quantify contamination status, evaluate ecological risk and enable cross-matrix source apportionment. Surface waters exhibited neutral to mildly brackish conditions. Severe oxygen depletion (DO: 0.1–4.0 mg/L), accompanied by elevated biological oxygen demand (0.17–4.5 mg/L) and chemical oxygen demand (43.2–420.2 mg/L), indicated organic loading and ecological stress. Dissolved nutrient concentrations were generally within Tamil Nadu Pollution Control Board guideline limits (TN: 0.1–6.34 mg/L; TP: 0.09–0.45 mg/L). In contrast, sediments and soils functioned as substantial nutrient reservoirs, with TN and TP reaching 5,387 and 32.5 mg/kg, respectively, reflecting long-term accumulation and legacy loading and underscoring the dominance of internal nutrient cycling. Metal concentrations in water were below detection limits, indicating minimal toxicological risk. Multivariate analysis demonstrated strong coupling among water, sediment and soil variables, particularly among EC, salinity, total dissolved solids, soil organic carbon, TN and TP. PCA indicated that most metals were predominantly lithogenic in origin, whereas Cd behaved as a distinct anthropogenic tracer across matrices. Ecological risk indices revealed generally low to moderate contamination, with localized hotspots. The results delineate a functional continuum in which surface waters act as transport pathways, sediments serve as geochemical sinks and soils integrate cumulative anthropogenic inputs. Internal nutrient cycling and organic matter accumulation emerged as the principal ecological stressors, while metal-related risks remained spatially limited. These findings emphasize the need for nutrient-focused, site-specific management and provide risk-informed evidence to support adaptive strategies for enhancing the long-term resilience of Tamil Nadu's inland wetlands. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
| Abstract: | This study evaluated ten inland wetlands in Tamil Nadu, India during May–July 2025 using a depth-integrated, multi-matrix (water–sediment-soil) assessment framework combining physico-chemical characterization, ecological risk indices and multivariate statistical modelling to identify dominant pollution stressors and inform sustainable wetland management. Water, sediment and soil samples were analysed following APHA (2017) standard methods. The integrated framework incorporated contamination factor, pollution load index, potential ecological risk index, geo-accumulation index, contamination degree, Pearson correlation, Kaiser–Meyer–Olkin test, Bartlett's test of sphericity and Principal Component Analysis (PCA) to quantify contamination status, evaluate ecological risk and enable cross-matrix source apportionment. Surface waters exhibited neutral to mildly brackish conditions. Severe oxygen depletion (DO: 0.1–4.0 mg/L), accompanied by elevated biological oxygen demand (0.17–4.5 mg/L) and chemical oxygen demand (43.2–420.2 mg/L), indicated organic loading and ecological stress. Dissolved nutrient concentrations were generally within Tamil Nadu Pollution Control Board guideline limits (TN: 0.1–6.34 mg/L; TP: 0.09–0.45 mg/L). In contrast, sediments and soils functioned as substantial nutrient reservoirs, with TN and TP reaching 5,387 and 32.5 mg/kg, respectively, reflecting long-term accumulation and legacy loading and underscoring the dominance of internal nutrient cycling. Metal concentrations in water were below detection limits, indicating minimal toxicological risk. Multivariate analysis demonstrated strong coupling among water, sediment and soil variables, particularly among EC, salinity, total dissolved solids, soil organic carbon, TN and TP. PCA indicated that most metals were predominantly lithogenic in origin, whereas Cd behaved as a distinct anthropogenic tracer across matrices. Ecological risk indices revealed generally low to moderate contamination, with localized hotspots. The results delineate a functional continuum in which surface waters act as transport pathways, sediments serve as geochemical sinks and soils integrate cumulative anthropogenic inputs. Internal nutrient cycling and organic matter accumulation emerged as the principal ecological stressors, while metal-related risks remained spatially limited. These findings emphasize the need for nutrient-focused, site-specific management and provide risk-informed evidence to support adaptive strategies for enhancing the long-term resilience of Tamil Nadu's inland wetlands. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 00496979 |
| DOI: | 10.1007/s11270-026-09484-3 |
