Author: Diptak Chakraborty
DOI Link: https://doi.org/10.70798/Bijmrd/03080005
Abstract: Freshwater ponds in suburban Kolkata are vital to the ecosystem, aquaculture, groundwater recharging, and daily life. Rapid urbanization and unregulated human inputs are straining aquatic systems, necessitating systematic water quality monitoring. This study explores seasonal and geographical variability in water quality indicators in five typical ponds in North 24 Parganas, West Bengal: Birati, Madhyamgram, Panihati, and New Barrackpore. Leased for aquaculture, the ponds are also utilized for idol immersion, street cleaning, and domestic washing. The ponds, bordered by dense residential areas, receive organic and chemical loads from these activities. The water samples were tested for phosphate, nitrate,biological oxygen demand (BOD), pH, dissolved oxygen (DO), and chemical oxygen demand (COD). Results vary significantly seasonally for all metrics. The seasonal patterns of atmospheric and water temperatures, which peaked at 36°C in summer and dropped to 11°C in winter, showed the strong climatic influence. Dissolved organic matter (DO) concentrations ranged from 4.02 mg/L in New Barrackpore to 8.15 mg/L elsewhere, indicating uneven organic loading and environmental stress. Pond pH showed different trends. Birati was alkaline, but New Barrackpore 2 had lower values (~7.3), indicating acidic pollution or abundant organic pollutants. BOD and COD values fluctuated, peaking at 4.24 mg/L and 6.9 mg/L, respectively, indicating organic matter intake from household activities and runoff. Nutrient dynamics analysis found seasonal maxima for phosphate (0.17-0.45 mg/L) and nitrate (1.4-5.2 mg/L) during monsoon months, indicating runoff and wastewater discharge influence. Continual high phosphate and nitrate levels in New Barrackpore 2 and Panihati reflect human stress and may impair eutrophication and fish production. The study emphasizes the importance of ongoing monitoring of suburban ponds because nutrient levels, fluctuations in dissolved organic matter (DO), biological oxygen demand (BOD), and chemical oxygen demand (COD) directly affect water quality, aquatic biodiversity, and aquaculture viability. The results illustrate how seasonal rains, poor waste management, and localized pollution worsen biological imbalances in these vital waterways. Community engagement, trash removal, and water quality checks are needed to safeguard suburban Kolkata’s freshwater ponds’ ecological health, socio-cultural functions, and economic value.
Keywords: Water Quality, Pollution, Seasonal Variation, Freshwater Pond, Suburban.
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