ASSESSMENT OF WATER QUALITY AND MICROALGAL DIVERSITY IN ADICHANALLOOR POND, KOLLAM, KERALA, INDIA

Abstract- The present study investigated the physico-chemical characteristics of water in AdichanalloorPond, a fresh waterpond ecosystem at Kollam district, Kerala, India over a three-month period from May to July 2025 at three sampling sites.The water parameters analyzed included temperature, pH, phenolphthalein alkalinity, total alkalinity, free CO2, dissolvedoxygen (DO), biological oxygen demand (BOD), hardness, total dissolved solids (TDS), calcium, chloride, and iron usingstandard methods. The study resulted surface water temperature ranged from 22°C to 33°C and the pH varied across the sites,indicating acidic to slightly alkaline conditions. Total alkalinity ranged from 120 to 250 mg/L, phenolphthalein alkalinity andfree CO2 were absent.Dissolved oxygen levels ranging from 4.2 to 8.9 mg/L, while BOD showed an increasing trendreflecting higher organic pollution. The Water Quality Index (WQI) values for Sites 1, 2, and 3 were 75.91, 76.43, and 97.82respectively, indicating poor to very poor water quality. The study revealed rich microalgal diversity in AdhichannalloorPond,identified 75 taxa from 35 families, including cyanobacteria, green algae, diatoms, desmids, and euglenoids. The dominantgroups were Desmidaceae and Naviculaceae (6 species). The presence of taxa such as Cosmarium, Closterium, and Spirogyraindicated good water quality, while cyanobacteria like Oscillatoria suggested nutrient-enriched conditions. The studyindicates that AdichanalloorPond is experiencing significant pollution caused by multiple factors, including eutrophication,human activities etc. such as bathing and washing, improper waste disposal, agricultural runoff and sewage discharge,chemical contaminants Hence the implementation of effective pollution control and watershed management strategies areurgently required.