Profiling pesticide concentrations for sustainable lake-use management in Lake Victoria Basin, Kenya: Are they within the recommended limits?

Abstract

It is crucial to have a coordinated mapping of banned pesticide contaminants in aquatic system to assess the risks associated with water and fish consumption. The objective of this study was to evaluate pesticide residue levels in Lake Victoria, Kenya, with respect to global thresholds using water and sediment samples collected from representative sites (Kisumu, Awach, Oluch, Mbita, Sondu, and Yala) between 2013 and 2018. The solvent-phase extraction (SPE) method was used to extract the samples. The results of the pesticide distribution analysis in natural water indicated higher mean HCH isomer residues in Winam Gulf compared to open waters. Since water is a vital resource for humans and fish, these concentrations are of particular concern. The highest observed concentration in sediment samples was the mean p,p’-DDT (58.80 ± 3.618 μg kg-1). Organochlorine residues in water samples were below the recommended limits set by the World Health Organization (WHO), but sediment samples exceeded these limits. As a result, there is a continuous need for regular monitoring of both local and regional data from point and non-point sources to ensure human and environmental health is safeguarded and to implement mitigation measures.