Reading, England – Microbes may be the key to breaking down and removing toxic compounds from crude oil and tar sands, according to studies by microbiologists from the University of Essex in the U.K.

Acidic compounds in crude oil and tar sands persist in the environment and can take up to ten years to break down. The researchers used a mixture of bacteria to achieve complete degradation of specific compounds in only a few days.

With supplies of high-quality light crude oil dwindling, producers are looking at alternative oil supplies such as tar sands, which contain the world’s largest supply of oil but are heavy or super-heavy crudes. The process of extraction and refining produces high concentrations of toxic by-products. The most toxic of these are a mixture of compounds known as naphthenic acids, which are resistant to breakdown and persist as pollutants in the water used to extract the oils and tar. This water is contained in large settling or tailing ponds.

The number and size of these settling ponds, containing lethal amounts of naphthenic acids, are growing daily, and it is estimated that there is around one billion cubic metres of contaminated water in Athabasca, Alberta alone, with the amount still increasing. The safe exploitation of tar sands depends on finding methods to clean up these pollutants.

“The chemical structures of the naphthenic acids we tested varied,” said Richard Johnson, who presented the research. “Some had more side branches in their structure than others. The microbes could completely break down the varieties with few branches very quickly; however, other more complex naphthenic acids did not break down completely, with the breakdown products still present. We are now piecing together the degradation pathways involved, which will allow us to develop more effective bioremediation approaches for removing naphthenic acids from the environment.”

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