An overview of aquifer pollution by petroleum hydrocarbons and possible remediation techniques

The degradation of groundwater quality as a result of incessant pollution by petroleum hydrocarbon contaminants (PHCs) resulting from oil spillage has enhanced research activities on the subsurface environment. The purpose of the research is largely to acquire better understanding of this environment in order to adequately control these intruding contaminants. Hence, this paper presents an overview of the occurrence of the uncontrolled releases of PHCs and their resulting adverse effects, with particular focus on the Nigerian environment. Geochemistry of petroleum, basic geochemical characterization techniques of the contaminants, its detection, behavior, fate and transport within the subsurface environment are discussed. In addition, various restoration techniques for the recovery of contaminants with different physical and chemical properties in groundwater and soils are presented. The following are observed: that recovery of PHCs in soils and groundwater is complex, and needs to be approached on a site specific basis; that groundwater degradation is a direct consequence of economic and industrial development, hence there is need for a form of trade-offs between groundwater protection and infrastructural developments. Conclusively, there is need for areas delineated for groundwater recharge and discharge to be cost effectively protected from PHCs by enforceable laws in order to forestall further groundwater quality degradation.