Assessment of Heavy Metal Distribution in Tilapia (Oreochromis niloticus) Samples from Uta Ewa Creek, Niger Delta, Nigeria

Abstract

The Uta-Ewa Creek is one of the largest aquatic commercial hubs in the Niger Delta, Nigeria. As a result of household activities, urbanization as well as the continuous industrial and agricultural growth, the health of this aquatic system is potentially deteriorating and under threat. This study was conducted to determine trace metal toxicity in tilapia species caught along the creek. Heavy metal concentration in fish tissue was analyzed using standard procedure. Results revealed that concentration of cadmium ranged from 1.708 to 1.963 mg/kg (mean = 1.82 ± 0.099 mg/kg), chromium: 0.003 to 0.016 mg/kg (mean = 0.0 ± 0.005 mg/kg), copper: 1.829 to 2.558 mg/kg (mean = 2.27 ± 0.354 mg/kg), iron: 2.104 to 2.601mg/kg (mean = 2.38 ± 0.189 mg/kg), lead: 0.004 to 0.067 mg/kg (mean = 0.04 ± 0.024 mg/kg), manganese: 1.987 to 2.485 mg/kg (mean = 2.21 ± 0.188 mg/kg) and zinc: 1.019 to 2.986 mg/kg (mean = 1.69 ± 0.811 mg/kg). The average heavy metal accumulation in fish tissue followed this sequence: Fe>Cu> Zn>Mn>Cd>Cr>Pb.The depth of accumulation of heavy metals revealed in this study was higher than the recommended levels by WHO, FEPA and USEPA. This indicated bioaccumulation. Inference from this study showed that, tilapia fish from Uta-Ewa Creek may be unsafe for human consumption. Consequently, appropriate monitoring of the health of this aquatic system is recommended.

Keywords: Heavy metals, bioaccumulation, concentration, monitoring, pollution