Bioremediation in Antarctic Soils

Introduction

Bioremediation has been considered a method for promoting the recuperation of contaminated environments at both higher and lower temperatures for at least four decades. Biodegradation by microorganisms appears to be the most efficient and economically viable method that poses the lowest risk to the environment compared with other approaches. Biodegradation techniques focus on utilizing natural biological activity to decrease toxic pollutant concentrations.

The bioremediation of petroleum hydrocarbons has been widely studied in different environments to build knowledge regarding biodegradation and the possible consequences after an oil spill. Several studies in the literature have shown that after an oil spill, various important processes may occur, including sorption, the abiotic processing of volatilization (chemical or photochemical), bioaccumulation and absorption by soil particles and biotransformation . The effect and efficiency of hydrocarbon degradation depends on several factors, including temperature, bioavailability, access to microbial cells, metabolic limitations, oxygen, alternate electron acceptors, nutrients and toxicity. However, despite the accumulated knowledge about biodegradation, the study of bioremediation in an Antarctic environment is minimal because the challenging conditions found in this continent alter and promote the rearrangement of all of the important factors.

Because of the geographic isolation and difficult life conditions, the Antarctic continent remained without human intervention until the XX century. Even today, the continent is used primarily as a research resource, and many research stations have thus been built in different regions to host researchers from various research areas. This occupation began in 1958 due to the International Geophysical Year; since then, fifty-five research stations have been built and are now occupied by more than five thousand people.

The annual human activities on the continent demand basic conditions such as energy generation, and oils of fossil origin are frequently used to supply this energy. Both exploration and the transport and storage of fuel oil promote increased accident risks. Fuel oil spills are among the main sources of contamination caused directly by humans in the Antarctic environment . The fuels and oils consist of alkanes and polyaromatic hydrocarbons (HPA) that are persistent in the environment  and have mutagenic, toxic and carcinogenic effects. However, the main oil blends used in the Antarctic, which are, consequently, the most present in chronic contaminations across the continent, consist primarily of C9-C14 aliphatic hydrocarbons . According to previous research, the cold environment can be more severely affected by contaminants than other environments, even at the same contamination level, because the necessary cold adaptions make these environments more sensitive.