Assessment of the Effects of Oil Pollution on Mangrove Forest in Niger Delta, Nigeria

Abstract

This research examines the impact of oil pollution on the ecosystem in parts of Bayelsa state, Southern Nigeria. It also identifies the effects this pollution has on the mangrove forest and the limitations to the creation of a sustainable environment. It identifies the major pathways for oil spill movement and the receptors of these pollutants within a site conceptual exposure model. The model uses remotely sensed data to determine the transition in states of the mangrove forest; it also uses field data to determine the concentration of hydrocarbon within the forest. The analyses were performed using a spatial transition model in GIS based environments. The results showed that the mangrove forest has reduced from 714 Km2 in 1987 to 382 km2 in 2009. Further analysis revealed that the greatest reduction in mangrove areas was between 2000 and 2005, there was 25% persistence in pixel to pixel match. On the other hand between 1987 and 2000 there was 45% persistence. NDVI analysis revealed a decline in the state of mangrove areas, and a corresponding increase in the incidence of oil spillage. The results revealed that 17.02km2 of the study area was impacted by oil spillage. The areas greatly impacted are; Lagosgbene creek, Nembe creek and Epebu. The concentration of hydrocarbon in the study area was higher than 25,000 μg/g in top soils, and above 15,000 μg/g in bottom soils and greater than 2,000 μg/g within the water bodies. Socio-economic activities are major contributors to the vegetation degradation. Therefore the study recommended a community based conservation for mangrove forest in the study area.