Asian Journal of Advances in Research

Dioxins and furans (PCDD/Fs) are persistent contaminants that can accumulate in aquatic sediments and contribute to ecological and human exposure. This study assessed PCDD/F concentrations in sediments from the lower reaches of River Ethiope, Delta State, Nigeria, and evaluated the associated ecological and human health risks. Twenty sediment samples were collected from sampling points near petroleum-handling facilities. Sediment extracts were prepared by ultrasonic solvent extraction and analysed by gas chromatography–mass spectrometry. Total concentrations of the seventeen analysed PCDD/F congeners ranged from 9.53 to 57.5 µg kg⁻¹, with OCDD as the dominant dioxin and OCDF as the dominant furan. Computed ∑TEQ values ranged from 1.34 to 8.52 ng TEQ g⁻¹ and exceeded the Canadian sediment quality guideline applied in the study. Non-cancer risk estimates yielded hazard index values of 34.1–216.6 for children and 4.77–30.32 for adults. Total cancer risk values ranged from 3.38 × 10⁻⁴ to 2.15 × 10⁻³ for children and from 2.37 × 10⁻⁴ to 1.50 × 10⁻³ for adults. Children consistently had higher estimated risks than adults across the sampled locations. The findings indicate substantial PCDD/F contamination of the sampled sediments and support continued environmental monitoring, measures to limit contaminant inputs, and actions to reduce direct exposure to contaminated sediment in communities using the river.