Estratègies de bioremediació en vessaments massius de petroli: aplicació en un cas hipotètic a Catalunya

Abstract

Bioremediation is an efficient technique to restore areas which have been contaminated by large oil spills. This method bases on the ability of microorganisms to oxidize the main oil compounds; hydrocarbons. While it is not a definitive solution, bioremediation allows us to some extent find an affordable balance between human beings and the environment. The goal of this study is to determine which bioremediation strategies could be applied in Catalonia in the hypothetical case of a large oil spill. The methodology of this research work consists of a primary research of literature sources based on general aspects of bioremediation and also the strategies applied in real oil spills. The effectiveness of bioremediation depends both on abiotic and biotic factors and its results differ in a maritime andor soil environments. Biotic factors are made up by the presence of hydrocarbon degrading microorganisms. On the other hand, abiotic factors are constituted, by environmental parameters regarding bioavailability and oxidation of pollutants, temperature, pH and redox potential. The main challenge to bioremediation in oceans and seas is the dynamics of the water. In contrast, in soil environments, the matrix heterogeneity and porosity are the most prevalent challenges. The efficacy of bioremediation is dependent upon the chemical composition of the oil. In the case of the Gulf of Mexico accident, with a lighter oil, the bioremediation rate was higher than in the case of heavier oils such as Exxon Valdez and Prestige. Weather conditions also affects bioremediation and destination of pollutants. Through supporting case studies, this paper will conclude that bioaugmentation is not a useful strategy and less frequent, whereas, biostimulation from fertilizers and dispersants can significantly improve bioremediation of oil. The characteristics of the Mediterranean climate and sea suggest that the implementation of bioremediation would be quick and efficient in the case of an oil spill in Catalonia. The strategy would be based on biostimulation with dispersants and fertilizers, discarding bioaugmentation. Finally, the lowscale application of ex situ bioremediation techniques and the lack of strategies that address the real needs of large oil spills would require the drafting of a proactive procedure proposal able to manage an oil pollution accident in Catalonia