LAUSR

Abstract Maintaining standard water quality of aquatic ecosystems requires continuous monitoring of water physicochemical and bacteriological characteristics. This study aimed at assessing water physicochemical and microbiological proprieties of Lake Tonga (northeastern Algeria). Water samples were collected monthly (January–June) from three different stations at different depths. Several physicochemical parameters (pH, electrical conductivity, turbidity, hardness, biological oxygen demand (BOD5), concentrations of suspended solid materials, dry residuals, dissolved oxygen, phosphate, nitrites, nitrates, ammonium, calcium, magnesium, chloride, potassium and sulfur dioxide) and bacterial group sdensity (total heterotrophic bacteria, total coliforms, faecal coliforms and faecal Streptococci) were measured. Physicochemical analysis of Tonga Lake water revealed a slightly alkaline environment pH (6.5 7.02 NTU, dry residues 5 mg/L, BOD5 0.1 mg/L, and NH4+ > 0.5 mg/L, Ca2+ 500 mg/L, K+ > 20 mg/L and sulfates