Degradation Of Some Petroleum Hydrocarbon Pollutants By Micro-Organism From Contaminated Tropical Soils

Background of Study

Petroleum is a major source of energy in the world and Nigeria is one of the major oil producing countries. Petroleum production and operations are often accompanied with serious ecological problems. Oil exploitation, exploration, transportation, consumption, attendant spills and disposals are some of the ways in which oil pollutants get into aquatic and soil environments. This has become a major concern to governments, individuals, environmental activists and the communities in the immediate environment. This problem has been further compounded by sabotage and vandalisation of pipelines in restive communities, particularly in the Niger-Delta region of Nigeria. Thus, oil pollution, despite the progress of recent years, will remain a controversial issue and a considerable problem.

Petroleum is a complex mixture composed primarily of aliphatic, alicyclic and aromatic hydrocarbons. There are thousands of individual compounds in every crude oil, the composition of each crude oil varying with its origin. As a result, the fate of petroleum pollutants in soil is complex (Atlas, 1995a). Essentially, crude oil components have been classified into four groups: the saturates, the aromatics, the asphaltenes (phenol, fatty acids, ketones, esters and porphyrins), and the resins (pyridines, quinolines, carbazoles, sulfoxides and amides) (Leahy and Colwell, 1990).