Abstract

Organochlorine pesticides (OCPs) are persistent, hydrophobic contaminants that bioaccumulate in aquatic ecosystems, posing ecological and human health concerns. This study investigated the occurrence, distribution, and health risks of OCPs in water, sediment, and silver catfish (Chrysichthys nigrodigitatus) from selected coastal creeks in Ondo State, Nigeria. OCP concentrations were determined using gas chromatography, while human health risks were evaluated using non-carcinogenic and carcinogenic hazard indices. Seventeen OCP congeners were detected in surface water (0.30–1.86 μg/L), sediment (0.24–1.95 μg/kg), and ten congeners in fish tissues (0.25–0.70 μg/kg). Heptachlor, BHC isomers, DDT metabolites, endrin aldehyde, and aldrin/dieldrin dominated the contamination profile. OCP levels in water exceeded WHO/FEPA permissible limits for aldrin/dieldrin, endosulfan, ddt, and heptachlor while concentrations of fish were generally within FAO/WHO limits except for aldrin/dieldrin. Seasonal variations were significant in water and sediment (p0.05). Overall contamination followed the trend: sediment > water > fish, indicating sediments as major contaminant sinks. Non-carcinogenic and carcinogenic hazard indices for fish consumption were far below acceptable thresholds in both seasons, suggesting negligible health risks. However, elevated aldrin/dieldrin levels underscore the need for continuous monitoring, improved pesticide management, and public awareness to prevent future contamination and safeguard the ecosystem and public health.

Key words: Fish, Hazard, Organic, Pollution, Sediment, Water