Quantification Of Organochlorine Pesticide Residue In Water And Sediments Of River Kibos-Nyamasaria Kisumu, Kenya

Abstract

Due to widespread use and potential for environmental damage, organochlorine pesticides (OCPs) are a prominent class of pesticides that have garnered concern on a global scale for decades. Inadequate regulation has resulted in the contamination of rivers and lakes worldwide. Pesticide residues in water and sediment are becoming more concentrated, posing major health issues for the local population. This study intend to determine the water physicochemical parameters and concentration of restricted or banned organochlorine pesticide residues, including Lindane, Endrine, Endosulfan, Dieldrin, Heptachlor, Hexachlorocyclohexane (HCH), Aldrin, Dichlorodiphenyltrichloroethane (DDT), methoxychlor and their isomers in water and sediments of river Kibos-Nyamasaria from ten sampling points during the wet (April–May) and dry (February–March) seasons. Gas chromatography with a mass spectrophotometer detector was used to determine the organochlorine pesticides residues levels. A muffle furnace was used to determine the soil's organic carbon and organic matter; a hot air oven was used to determine soil moisture; a lab conductivity meter was used to measure soil conductivity; and a pH meter was used to measure water and soil pH. Soil pH ranged from 6.20±0.05 to 7.26±0.06, conductivity ranged from 44.43±0.31 to 233.63±0.25 μs/cm, sediment moisture ranged from 13.14±0.03 to 26.34±0.03%, organic matter ranged from 2.95±0.06 to 9.43±0.11%, organic carbon ranged from 1.71±0.04 to 5.47±0.07%, and pH in water ranged from, 6.93±0.06 to 7.90±0.02 respectively in both seasons. Aldrin pesticide residue had the highest concentration of 8.33±0.58 μg/L during the wet season, while α-HCH had the highest concentration of 8.27±0.06 μg/L during the dry season and in the wet season α-HCH recorded 3.47±0.06 μg/L in river water. In sediments α- HCH had the highest concentration of 3.66±0.02 μg/kg in the wet season and 3.81±0.03μg/kg in the dry season at the entry point to Lake Victoria. Among all the DDTs isomers, p, p’- DDD had the highest concentration of 0.09±0.02 μg/L in the wet season and 0.03±0.02 μg/L in the dry season in water samples and sediments samples, p, p’- DDD had the highest concentration of 3.26±0.03μg/kg in the wet season and 3.28±0.06 μg/kg in the dry season at the entry point to Lake Victoria. o, p’- DDE had the least concentration of 0.32±0.02 μg/kg during the wet season and 0.34±0.08 μg/kg during the dry season in sediment samples. All the DDT isomers detected had a higher concentration in the wet season than the dry season in water samples, with most of them above 0.1 μg/L, which exceeds the maximum residues limits (MRLs) of WHO at the swamps or entry point to Lake Victoria. In the water and sediments from ten sampling points, nineteen pesticide residues were found and their concentrations increased downstream as the river approached Lake Victoria. The correlation between soil pH, conductivity, soil moisture, organic matter, and organic carbon with all 19 organochlorine pesticides studied showing significantly positive correlation at (P≤0.01). It is necessary to establish measures to reduce the pesticides and find potential sources of the banned pesticides because several pesticides were present at levels beyond the advised limits.