Assessment of surface water quality in the lower Sebou by physicochemical and microbiological approach and the impact of tributaries (Oued Beht and Oued Swaret) during the summer season

Abstract

The study consists in assessing the quality of the surface waters of the Lower Sebou (from dam to Sebou mouth), by studying the impact of anthropic activities and the tributaries flowing into the Sebou (Oued Beht and Oued sawaret), and by analyzing the various physico-chemical and bacteriological parameters such as : temperature, pH, conductivity, TSS, turbidity, DCO, DBO5, total phosphorus, NO - , NO - , NH 4 + , SO 2- , Cl - , Mg 2+ , Ca 2+ , alkalinity, total and faecal coliforms bacteria, total and faecal streptococci. Nine stations were sampled in mid-September 2021. The water analyzed showed high values: for temperature, from 24.7 to 31.1°C; for alkalinity, from 170.80 to 207.40 mg/L; for total phosphorus, from 0.01 to 1.75 mg/L; for ammonium, from 0.03 to 16.56 mg/L; for nitrite from 0.206 to 0.676 mg/L; for turbidity from 23 to 596 mg/L; for chemical oxygen demand from 50.88 to 168 mg/L; for biochemical demand for oxygen in 5 days from 16 to 58 mg O2/L; for faecal coliforms from 30 to 4500000 B/ml. The statistical analysis is encouraging, showing a temporal evolution in the overall quality of the lower Sebou.