UTTAR PRADESH JOURNAL OF ZOOLOGY

Sukhna Lake, a prominent man-made reservoir in Chandigarh, India, serves essential ecological and recreational roles but is increasingly vulnerable to pollution and seasonal stresses. This study investigates the spatio-temporal variations in the lake’s water quality by analysing key physicochemical parameters (pH, dissolved oxygen [DO], biochemical oxygen demand [BOD]) and heavy metal concentrations (Pb, Cd, Cu, Mn) across three seasons—winter, spring, and summer. Water samples were systematically collected from three representative locations and analysed using standard APHA protocols. Results revealed significant seasonal differences (p < 0.05) in most parameters. Spring exhibited the most favourable water quality, with the highest DO (12.50 ± 0.50 mg/L), lowest BOD (1.00 ± 0.00 mg/L), and moderately alkaline pH (7.50 ± 0.50), indicating high photosynthetic activity and lower organic load. Conversely, summer was the most ecologically stressed season, marked by low DO (6.83 ± 1.04 mg/L), high BOD (2.67 ± 1.44 mg/L), and acidic pH (6.32 ± 0.18), reflecting elevated microbial decomposition and pollutant concentration due to high temperatures and reduced dilution. Heavy metal concentrations remained within WHO/EPA limits but showed seasonal patterns. Lead and copper levels peaked slightly in spring (0.0050 mg/L and 0.0100 mg/L, respectively), while cadmium showed higher values in winter and summer (0.0017 mg/L), suggesting seasonal runoff and anthropogenic influence. The study concludes that Sukhna Lake’s water quality is highly sensitive to seasonal dynamics, particularly during summer months. These findings emphasize the need for season-specific management strategies, including enhanced runoff control, pollution mitigation, and continuous monitoring.