Hassane Mansour^{1, 2,}, Jean Marie Dikdim Dangwang³, Theophile Maoudombaye⁴, Yoradji Nadjilom⁴, Albert Ngakou², Guy Bertrand Noumi³

Water as essential for life is considered everywhere as a fundamental and indispensable element of natural resources. The aim of the present study was to physico-chemically assess the properties of water from Chari river along the Banda township in the Middle-Chari region in Chad. Water samples were taken from five different sites (ChS1-ChS5) along the Chari river during the dry (February) and wet (July) seasons of 2023. The studied parameters were temperature, pH, electrical conductivity, turbidity, Total Disolved Solids, Chemical Oxygen Demand, Suspended Materials, total nitrogen, total phosphorus, Nitrate, Nitrite and Sulfate that were compared between sampling sites. In situ analyses revealed a significant variation in temperature between sampling sites, ranging from between 26.01-28.52°C in the dry and 29.6-33.13°C in the wet seasons. Whereas the electrical conductivity was comprised between 53.8 and 146.63 μS/cm, the Total Disolved Solids varied from between 28.87 and 73.47 mg/L. The pH values remained within the maximum limits set by Chad's National Drinking Water Standards (6.5-8.5), except for station ChS1, where a slightly acidic pH was observed. In the dry season, water quality was safe for COD, except for site ChS5, based on the SEQ-water classification. Apart from the sampling site ChS1 that was contaminated with nitrate in the wet season, water from all the other sites was not at risk for nitrate concentration. During the dry season, the concentrations in nitrite at sites ChS1, ChS3 and ChS4 were above the WHO (2002) norm, which is 0.1 mg.L^-1, thus were at risk as drinking water. The registered turbidity values were positively correlated to SM in the dry season, but were largely above the acceptable limits for drinking water which is set to 5 NTU. The physico-chemical pollution of water from Chari river was mostly originated from agricultural, industrial and urban activities. Although the risk levels quality of studied water parameters were revealed weak for some, it seems important to set up a monitoring system to reduce the water pollution attributed to the above physico-chemical properties of the Chari river.

water, pollution, Chari river, physico-chemical properties, Chad