Assessment and Toxicological Risk of Organochlorine Pesticide Residues in Water from River IBI, North Eastern Nigeria

The increasing use of pesticides for agricultural productivity and vector control has raised serious environmental and public health concerns, particularly regarding organochlorine pesticides (OCPs) due to their persistence, bioaccumulation, and toxicity. This study assessed the occurrence and risk implications of OCP residues in surface water from River Ibi, Northeastern Nigeria, a vital resource for domestic, agricultural, and fishing activities. Water samples were collected from five locations along the river and extracted using USEPA Method 3510, followed by analysis with Gas Chromatography equipped with an Electron Capture Detector (GC-ECD). Physicochemical analysis revealed slightly alkaline conditions (pH 8.27–9.01) and temperatures ranging from 20.62 to 27.67 °C, conditions that favor OCP stability in tropical aquatic environments. Sixteen OCPs were detected in water, with total concentrations ranging from 2.126 µg/L to 7.422 µg/L across sampling sites. β-BHC was the dominant compound (mean = 5.224 µg/L), while aldrin recorded the lowest concentration (0.217 µg/L). Contamination factor values (2.53–10.45) indicated moderate to high contamination of the river water. Human health risk assessment revealed that carcinogenic risks for β-BHC, dieldrin, heptachlor, and aldrin exceeded USEPA acceptable limits, particularly at downstream locations. Dermal exposure assessment showed that children are more vulnerable than adults. The findings indicate significant contamination of River Ibi water by OCPs, posing potential ecological and public health risks and underscoring the need for continuous monitoring and stricter pesticide control