Nikeeta S. Keni and Vinda Manjramkar
Abstract
The present study evaluated seasonal variations in water quality parameters of two ecologically important regions of Thane Creek, Airoli and Vashi, located along the eastern coast of Mumbai, Maharashtra, and assessed the influence of natural and anthropogenic factors. Water samples were collected during three distinct seasons: pre-monsoon, monsoon, and post-monsoon, and analyzed for physical, chemical, and biological parameters, including turbidity, pH, salinity, total dissolved solids (TDS), acidity, alkalinity, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), nitrate, phosphate, and total hardness, following standard procedures. Turbidity ranged from 0.9 to 25 NTU, with elevated values during pre- and post-monsoon, indicating higher suspended matter. pH remained near neutral, suggesting moderate buffering capacity. Salinity varied between 0.66 and 49.2 ppt, reflecting tidal influence and monsoonal freshwater dilution. TDS ranged from 690 to 33,700 mg/l, highlighting substantial dissolved solids from industrial and domestic sources. Acidity (7.76-200 mg/l) and alkalinity (60-432 mg/l) exhibited seasonal fluctuations, while DO levels ranged from 0 to 8.8 mg/l, with critically low concentrations during non-monsoon periods. BOD (24-931 mg/l) and COD (9.6-300 mg/l) indicated high organic pollution, particularly pre- and post-monsoon, whereas nitrate and phosphate remained relatively low, reflecting limited nutrient loading. Significant seasonal variations were influenced by tidal fluctuations, rainfall, and anthropogenic inputs. Water quality deteriorated during pre- and post-monsoon due to industrial effluents and domestic sewage, whereas marginal improvement occurred during monsoon due to dilution. These findings emphasize the need for continuous monitoring and effective management strategies to mitigate pollution and enhance the ecological health of Thane Creek.