The study establishes a baseline for the physicochemical quality of the surface waters of the Casamance Estuary (Senegal). Seasonal sampling (2022-2023) at six stations involved taking in situ measurements of temperature, salinity, dissolved oxygen and pH, as well as sampling the surface water. These samples were analysed using spectrophotometry to determine the concentrations of sulphates, nitrates, nitrites, ammonium and phosphates. Results show marked seasonal but limited spatial variability; most parameters meet Water Framework Directive (WFD) “good” thresholds except for consistently high sulphate. The work provides initial reference values for future impact tracking of oil exploitation in Senegal.
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