Hydrocarbons

Where does hydrocarbon contamination come from?

Hydrocarbons can be introduced into the environment via incomplete combustion of fossil fuels, accidental discharge during transport, the disposal of petroleum products and other organic wastes, incineration of refuse and wastes, and various industrial processes. They can also be produced as a result of natural processes including forest fires and volcanic eruptions. Certain hydrocarbons known as polycyclic aromatic hydrocarbons (PAHs) are found in soil at wood preservation plants and gas manufacturing facilities.

 

Why are hydrocarbons toxic?

The inertness of high molecular weight hydrocarbons coupled with low solubility in water and strong lipophilic character lead to high accumulation levels and persistence. Some hydrocarbons (such as benzene) have been shown to be carcinogenic. In the case of large industrial oil spills, the oil can actually suffocate living organisms and destroy entire ecosystems. Excess hydrocarbons in aqueous environments can deplete the supply of oxygenating molecules, leading to anoxic conditions.

 

Why use bioremediation?

Although they can be eliminated abiotically through photooxidation, PAHs with more than three rings are more difficult to remove. High-molecular weight PAHs have a low bioavailability due to their strong adsorption onto the soil organic matter, high resonance energy, and toxicity. Numerous microorganisms – bacteria, algae, and fungi – are capable of metabolizing hydrocarbons.