Alkylphenols and Alkylphenol Ethoxylates in Freshwater Fish: Levels and Human Health Risk Estimates from River Benue, Central Nigeria

Alkylphenols (APs) and Alkylphenols ethoxylates (APEs), are ubiquitous estrogenic chemicals, widely distributed in fish due to their persistence and lipophilicity. This study determined levels of APs and APEs, and the associated human health risk in two fish species, 16 Labeo coubie (African carp) and 16 Hydrocynus vittatus (African Tiger fish) sampled quarterly from River Benue, central Nigeria between September 2019 and June 2020. Compounds were identified and quantified using Gas Chromatography with Mass Spectrometric detection (GC-MS). Levels of twenty APs (∑20APs) in Labeo cubie ranged from ND-16.0 ng g-1 wet wt, with total and maximum values of 94.5 ng g-1 wet wt, and 16.0 ng g-1 wet wt respectively. Residues of four APEs (∑4APEs) ranged from ND-3.1 ng g-1 wet wt, total of 5.0 ng g-1 wet wt, and maximum of 3.1ng g-1 wet wt respectively. In Hydrocynus vitatus, ∑20APs ranged from ND-27.8 ng g-1 wet wt, total and maximum of 205 and 27.8 ng g-1 wet wt, respectively. Estimated risk from ingestion of compounds in Labeo cubie and Hydrocynus vitatus by adult and children indicate no immediate potential harm as the hazard quotient (HQ) value was less than one (HQ < 1). However, children could suffer higher body burdens of these pollutants than adults if they are fed with these fish. This study provides baseline data on levels and estimated human health risk from ingestion of these two species of fish contaminated by APs and APEs to regulatory agents and future researchers.