QUANTIFICATION OF POLYAROMATIC HYDROCARBONS (PAHS) IN THE SEDIMENT OF BARRACKS-RIVER, NORTH CENTRAL NIGERIA

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants of significant environmental and health concern due to their carcinogenic, mutagenic, and teratogenic properties. This study investigated the concentrations, distribution, and sources of PAHs in sediment samples from Barracks-River, Lokoja, North Central Nigeria. Sediment samples were collected from four stations (PS1–PS4) representing areas with varying anthropogenic activities and analyzed using Soxhlet extraction followed by gas chromatography with flame ionization detection (GC-FID). Results revealed that total PAH concentrations ranged from 7.99 ± 0.07 ppm at PS4 to 15.02 ± 0.07 ppm at PS1, with naphthalene being the most dominant compound (3.44–10.83 ppm). Low molecular weight PAHs (LMW-PAHs) such as naphthalene, fluorene, and anthracene were more prevalent, indicating strong petrogenic influences from petroleum residues, car wash operations, and block-making industries, while the presence of chrysene suggested pyrogenic inputs from biomass burning and incomplete combustion. High molecular weight PAHs (HMW-PAHs), including benzo(a)pyrene, were below detection limits, likely due to stronger adsorption and faster degradation under tropical conditions. The spatial variation in PAH levels reflected localized pollution pressures, with PS1 and PS3 showing higher contamination due to domestic discharges, industrial runoff, and construction activities. The predominance of bioavailable LMW-PAHs underscores potential ecological risks, particularly to benthic organisms and through bioaccumulation in aquatic food webs. These findings provide baseline data for environmental monitoring and highlight the need for improved waste management, stricter pollution control, and continuous monitoring to safeguard aquatic ecosystems and public health in Lokoja.