IMPACTS OF OIL POLLUTION ON THE HEAVY METAL CONTENT OF THE MANGROVE ECOSYSTEM IN SOME STATES OF THE NIGER DELTA

Abstract

The Niger Delta is the hub of crude oil exploration and exploitation activities in Nigeria. Oil activities have given rise to numerous incidences of oil spills into the environment, especially the mangrove ecosystem. This study investigates the impacts of oil spills on the mangrove ecosystem. Sediment samples were obtained from the mangrove rhizosphere, in three areas, two in areas of high oil activities; (Nembe and Okrika) and the third (Okpare) devoid of oil activities. The sediments were analysed for their physiochemical parameters. The results showed the presence of some heavy metals (Zinc-3.18 – 3.6 mg/kg; Chromium-1.57 - 1.67 mg/kg; Lead-1.5 – 1.65 mg/kg; Copper-1.77 – 2.03 mg/kg and Cadmium-1.69 – 1.71mg/kg) in the sediments. There was no significant difference (p?0.05) in the concentration of heavy metals at the three sites. The pH of the sediments was acidic, ranging from 5.13 - 5.43. There was also presence of hydrocarbons and oil-grease in high concentrations. The study concludes that the mangrove ecosystem in the entire Niger Delta appears to have been impacted upon by oil activities.