Assessment of Total Hydrocarbon Content in Water, Sediment and Fish from Koniju-Toru Upper Bonny Estuary, Nigeria

A river’s physical, chemical and biological states indicate the quality of the aquatic system. This study assessed the level of total hydrocarbon content (THC) and other water and sediment characteristics in the Koniju-toru River of Okrika – an estuary of the Bonny River – for three months. Surface water, sediment and fish samples were collected from three stations (upstream, midstream and downstream) for three months. Composite samples of each station were tested for pH, total dissolved solids (TDS) and dissolved oxygen (DO) in-situ using HANNA multi-parameter meter while conductivity, nitrate, sulphate, phosphate, chloride and biochemical oxygen demand (BOD) were determined in the laboratory. Spectrophotometry was used for the determination of hydrocarbon content in the samples. The hydrocarbon content in surface water, sediment and fish ranged from 0.05 -0.12 mg/L, 2.13 – 3.83 mg/kg and 0.24 – 0.35 mg/kg, respectively. Other results characterizing the surface water included; pH (6.62 – 6.73), temperature (26.10 – 26.53 ℃), TDS (8888.3 – 10972.3 mg/L), chloride (6697.6 – 7598.3 mg/L), sulphate (259.1 – 346.5 mg/L), nitrate (0.17 – 0.29 mg/L), phosphate (0.002 – 0.066mg/L), DO (4.10 – 4.86 mg/L) and BOD (2.02 – 2.22 mg/L). Parameters in sediment ranged as follows; pH (5.12 – 5.60), alkalinity (50.3 – 100.3 mg/kg), chloride (504.7 – 604.8 mg/kg), sulphate (125.2 – 183.6 mg/kg), nitrate (0.11 – 0.30 mg/kg) and Total Organic Matter (0.60 – 0.73 mg/kg). Statistical tests showed significant difference (p