Boma, M. and Nwoke, I. B. RISK ASSESSMENT AND SOURCE IDENTIFICATION OF SOME PHENOLIC ENDOCRINE-DISRUPTING CHEMICALS IN WATER, SEDIMENT, AND CLARIAS GARIEPINUS FROM OKRIKA AXIS OF BONNY RIVER

Abstract

This study investigated phenolic EDCs in surface water, sediment and Clarias gariepinus (African Sharptooth Catfish) from four sampling locations along the Okrika axis of Bonny River, Rivers State, Nigeria. Fish were obtained from local fishermen and water and sediment samples were collected from representative stations. Ten phenolic EDCs (including Phenol, 3-chlorophenol, 3-methylphenol, 2, 3-dimethylphenol, 2,4-dimethylphenol, 2,5-dimethylphenol, 2-cyclohexyl-4,6-dinitrophenol, nonylphenol (NP), octylphenol (OP), and bisphenol A (BPA)) were analyzed by Gas Chromatography–Mass Spectrometry (GC-MS). EDCs in water ranged from 0.81±0.01 to 4.72±0.02, in sediment from 0.44 ± 0.02 to 20.84 ± 0.03, and in Clarias gariepinus from 0.71±0.02 to 4.81±0.01. Concentration data were evaluated using contamination factor (CF) and pollution load index (PLI); accumulation was assessed by bioaccumulation factor (BAF) and biota–sediment accumulation factor (BSAF); and human/ecological risk was estimated via estimated daily intake (EDI), hazard quotient (HQ) and hazard index (HI). Results showed widespread contamination of the Bonny River by both EDCs. Phenolic compounds, particularly nonylphenol, octylphenol and bisphenol A—were pervasive in water, sediments and fish, and CF/PLI metrics flagged these chemicals as primary contributors to local pollution. Collectively, the data indicated that Bonny River is chemically stressed by mixed inputs from oil-related activities, industrial effluents and domestic discharges. The concurrence of elevated contamination indices, strong bioaccumulation and HI exceedances highlights an urgent need for monitoring and regulatory enforcement.