Hydrocarbons as contaminants can be introduced into aquatic environment through natural and anthropogenic sources. The study assesses the distribution and concentration level of hydrocarbons in the bottom sediment of the dockyard creek in Port Harcourt, Nigeria. Hydrocarbons such as Total Petroleum Hydrocarbon (TPH), benzene, Toluene, ethyl benzene and xylene (BTEX), polycyclic aromatic hydrocarbons (PAHs) and total hydrocarbon content (THC) were analysed using Gas Chromatographic (GC). The mean concentrations of BTEX trend as downstream (43.92 ± 8.89 mg/kg) > upstream (0.34 ± 0.28 mg/kg) > midstream (0.047 ± 0.03 mg/kg) > control (0.02 ± 0.00 mg/kg) and within USEPA limit except at the downstream. The mean concentrations of PAHs trend as downstream (58.87 ± 4.33 mg/kg) > upstream (6.68 ± 4.08 mg/kg) > midstream (4.06 ± 1.66 mg/kg) > control (0.65 ± 0.07 mg/kg). The levels of PAH in all zones except Downstream were below FEPA standard for PAH in water sediment (10.0 mg/kg). The mean concentrations of TPH trend as downstream (2646.0 ± 41.05 mg/kg) > upstream (667.6 ± 18.81 mg/kg) > midstream (335.8 ± 126.7 mg/kg) > control (40.09 ± 4.99 mg/kg). The levels of TPH in all zones except control (40.09 mg/kg), exceeded FEPA standard for TPH in water sediment (100 mg/kg). The THC concentration range from 1,232.6 to 1,315.6 mg/kg at upstream, 1,040.7 and 1,432.6 mg/kg at midstream, 1,058.3 to 1,515.6 mg/kg at downstream and 158.3 to 212.9 mg/kg at the control. The findings emphasize the need for improved wastewater treatment and stricter regulations various anthropogenic activities.

Physical Sciences Hydrogeology and Watershed Science https://doi.org/10.70726/hws.2025.210108