Physico-chemical characterization of watercourses in Comoé national Park (North -East Côte d’Ivoire; West Africa)

Résumé fourni par la source

This study focused on the abiotic characterization of the Comoé National Park's watercourses in order to assess the quality of the environment. Measurements were taken at six sampling stations between May 2022 and March 2023. Physico-chemical parameters (temperature, electrical conductivity, dissolved solids, pH, dissolved oxygen) were measured in situ using a digital multi-parameter. Ionic compounds (phosphates, nitrites, ammonium, total chlorine) were quantified in the field using mini-photometers and HANNA kits containing assay reagents. Finally, organic pollution indicators (COD and BOD5) were determined in the laboratory according to standard protocols. The results reveal a wide range of values: temperature (22.79-32.52°C), pH (6.17-8.88), dissolved oxygen (0.8-10.54 mg/l), conductivity (23-87.2 µS/cm), TDS (11-63 mg/l), phosphate (0, 0-2.35 mg/l), nitrite (0.001-1.44 mg/l), ammonium (0.0-46.56 mg/l), total chlorine (0.0-2.3 mg/l), COD (0.0- 231.79 mgO2/l) and BOD5 (0.0-35.5 mgO2/l). Kruskal-Wallis and Mann Whitney tests showed significantspatial-seasonal differences for some variables. The study revealed that the Comoé River's parameter values more frequently exceed threshold values (T°: 24-25.5°C; O2: 8-6 mg/l; NH4+ : 0.1-0.5 mg/l; NO2-: 0.03 0.3 mg/l; PO4 3 : 0.1-0.5 mg/l; DCO: 20-30 mgO2/l and BO5:3-6 mgO2/l), indicating a more marked state of degradation compared with the rivers of the Comoé National Park.