Investigation of Heavy Metals and Oxidative Stress in Sarotherodon melanotheron Harvested at Abule-Ado Lagoon, Lagos, Nigeria

Introduction: Contamination of aquatic life by heavy metals is common in petroleum polluted environment. Abule-Ado Lagoon (AAL) in Lagos State, Nigeria, houses a number of private petroleum depot and there is large scale oil spillage in the environment. Bioaccumulation of heavy metals in tissues of fish harvested in polluted areas may pose health risk to consumers

Purpose: Therefore this study was designed to assess the bioaccumulation of heavy metals and oxidative stress in Sarotherodon melanotheron harvested at AAL and compared with the control, harvested at Iyana-Iba Lagoon, Lagos.

Methods: Ten female fishes each were harvested from test and control sites and the concentrations of Iron (Fe), Lead (Pb), Cadmium (Cd), Chromium(Cr) and Nickel (Ni) were determined in the gills, liver and flesh  using atomic absorption spectroscopy.  The  toxicity and oxidative stress in the fishes were investigated by monitoring aspartate amino transferase (AST), alanine amino transferase (ALT), malondialdehyde (MDA), reduced glutathione (GSH) and  super oxide dismutase (SOD) activities in the liver and gills.

Results: Fishes harvested from AAL showed marked (P < 0.05) increase in the tissue concentration of the metals as compared with control. The decreasing trend of metals in the tissues of harvested fish was Fe> Pb>Cr >Ni>Cd. Fishes collected at AAL showed a significant (P < 0.05) increase in GSH, MDA, SOD and AST activities in the gills and liver when compared with those taken at the control site.

Significance: Our results suggest that Abule-Ado Lagoon is polluted with heavy metal and fishes inhabiting the lagoon may be vulnerable to stress and diseases, which may make them unsafe and unhealthy for human consumption.