Mapping Human-Induced Spatio-Temporal Shifts in Water and Sediment Quality in a Tropical Urban Estuary

Meena J. Poonja, Keyur Patel, Sandeep R. Garg

Abstract: Objectives: This study examines long-term spatio-temporal variations in hydro-chemical and sediment quality of Thane Creek over 2005-2025, focusing on key water quality parameters, sediment contamination, seasonal-spatial heterogeneity across creek segments, and long-term degradation trends in this urban estuary. Methodology: Twenty-seven monitoring sites covering the Upper, Middle, and Lower creek segments were analyzed. Water quality parameters (DO, BOD, COD, pH, temperature, nutrients, and microbial indicators) were measured using standard American Public Health Association (APHA) methods. Sediment contamination was evaluated using Contamination Factor, Pollution Load Index, and Geo-accumulation Index. Spatial and seasonal variations were assessed using ANOVA and correlation analysis, with long-term datasets used to examine salinity-nutrient relationships. Results: The Upper Creek showed severe degradation, with hypoxia (Dissolved Oxygen: 2.1 ± 0.5 mg/L), high organic loads, elevated nutrients, and moderate-to-strong sediment contamination (Pollution Load Index (PLI): 3.2; Pollution Load Index (Igeo): 2.6). Monsoon dilution temporarily reduced pollution loads, followed by rapid post-monsoon recovery. Strong spatial heterogeneity (p < 0.001) and an inverse salinity-nutrient relationship (r ≈ -0.88) indicated freshwater-driven enrichment. Conclusion: Persistent upstream degradation is driven by untreated sewage, industrial inputs, and habitat loss, while tidal flushing improves downstream conditions, highlighting the need for improved wastewater management and habitat restoration.

Keywords: Thane Creek, estuarine degradation, water quality, sediment contamination, eutrophication, monsoon dynamics

How to Cite?: Meena J. Poonja, Keyur Patel, Sandeep R. Garg, "Mapping Human-Induced Spatio-Temporal Shifts in Water and Sediment Quality in a Tropical Urban Estuary", Volume 15 Issue 1, January 2026, International Journal of Science and Research (IJSR), Pages: 646-654, https://www.ijsr.net/getabstract.php?paperid=SR26109131038, DOI: https://dx.doi.org/10.21275/SR26109131038