El Hadji Moussa Diop^{1, 2,}, Kalidou BA¹, Demo KOITA¹, Alioune Badara PAYE³, Houéfa Bossèdé Glorieuse Ange-Carelle DANSOU²

Pink lake, an emblematic ecosystem of Senegal with a strong tourist attraction, is today facing a worrying environmental and ecological degradation. Thus, this study aims to assess the quality of the lake's waters, through a rigorous scientific approach combining physicochemical analyses and statistical processing, in order to identify the links between variables and better understand the origin of pollution. The study was based on sampling carried out in October 2024 at five stations on the lake. A number of parameters such as pH, conductivity, salinity, TDS, COD, heavy metals, pesticides and other hazardous substances were determined. The analysis results showed average values of COD (217.77 mg/L) and TDS (282002 mg/L), critical compared to environmental standards, reflecting an excessive organic and mineral load. Furthermore, the average salinity of the lake (181456.2 mg/L) decreased compared to the threshold value (380000 mg/L). According to multiple linear regression modeling, pH prediction was statistically associated with salinity, COD and conductivity, with interactions between salinity and COD as well as between salinity and conductivity modulating this effect. The model showed excellent data fit with an R² of 0.9967 and a p-value of 0.0008319 indicating its significance. Widespread contamination of the lake by heavy metals was also observed. Some, such as Pb (0.0106 mg/L), As (0.6712 mg/L), Cd (0.0661 mg/L) and Ni (4.6930 mg/L), had high levels exceeding regulatory thresholds with a particularly alarming concentration at the surface of the first station. The presence of pesticides, plasticizers and hydrocarbons was also detected in the water, thus indicating pollution of agricultural, domestic and industrial origin. Thus, this study highlighted an advanced deterioration in the water quality of pink lake, with potential risks for human health and the aquatic ecosystem. These findings call for urgent measures for the restoration and sustainable management of this natural heritage.

Pink lake of Senegal, pollution, multiple linear regression, heavy metals, pesticides, PCA