Oil spills: Environmental consequences and recovery strategies

Petroleum perhaps is one of the most important substances to the modern society, due to its wide use in the most diverse productive sectors. Besides serving as raw material to the production of plastics and other compounds, it is the fuel source used in the production of electric energy, in industries and in the different transport sectors. However, the ecosystems located in areas of extractions, processing and distribution of petroleum end up being highly susceptible to the direct and indirect impacts of these activities, as well as those located in their transport route. As the large extraction fields are located in coastal areas, these environments are, generally, the most affected, although other ecosystems also suffer influence of the petroleum activities. Oils spills and leakages provoke immediate effects into the environment, easily viewed by the generalized mortality of animals and consequent ecosystems losses, but also provoke more persistent effects, such as alteration of the animals behaviour and permanence of compounds derived from petroleum in the food webs. Accidents with petroleum are unpredictable and the resources needed to minimize their impacts, often, are not liable to an immediate application. Among the strategies developed to recover the impacted environments, there are the mechanical cleaning methods, use of chemical dispersant products and use of bioremediation treatments. Cleaning methods of areas contaminated by petroleum are only considered effective when they prevent the migration of this pollutant to more sensitive ecosystems. Now, the bioremediation has been considered a -green' alternative for treatment of dangerous contaminants since it uses organisms naturally able to reduce, remove and transform the organic and inorganic pollutants. The success of this process depends on it natural biodegradability, bioavailability and optimization of the biological activities related to the pollutant. Among the strategies available to perform the natural bioremediation there are the natural attenuation, bioventilation, biomagnification, biostimlation, landfarming, composting and phytoremediation. In this chapter it will be discussed the concepts related to the impacts caused by petroleum and its derivatives, as well as the ecological consequences of some petroleum accidents and the efficiency of the application of the environmental decontamination techniques, such as bioremediation, since this is an effective strategy, economically viable and that provides a lower environmental impact.