Oil Spills in Water

Among the most dangerous of all water pollutants is fuel oil. Oil spills from tankers at sea or leaks from underground storage tanks on land are very difficult to control as oil tends to spread very fast, affecting a large area in a very short time. They are a major menace to the environment as they cause severe damage to surrounding ecosystems. Oil spills at sea decrease the oxygen level in the water and cause grave harm to the creatures living in the sea. Since crude oil is lighter than water, it floats on the surface and poses the threat of swift-spreading fire.
Oil spills are rather common as oil tankers can meet with accidents either in deep sea or offshore, while waiting to be loaded or unloaded. During the Gulf War, several oil reservoirs were destroyed at sea and the effect on marine life was devastating. Seabirds and fish were washed ashore, their bodies covered with oil. On land crude is transported through pipelines or tankers which can get damaged and spew out crude oil over the land, thereby contaminating it. Enormous quantities of organic and inorganic compounds are released into the environment each year as a result of human activities.

In some cases these releases are deliberate and well regulated (e.g. industrial emissions) while in other cases they are accidental (e.g. chemical or oil spills). Petroleum and its products are one of the most common environmental pollutants. They are a fire hazard, threat to marine life, and a source of air and groundwater pollution. They contaminate land and water bodies by accidental spills like the Alaska Oil spill in 1989 and oil spills during the Gulf War, leakage from pipelines, and other human activities. Detoxification of the contaminated sites is expensive and time consuming by conventional chemical or physical methods.

Bioremediation consists of using naturally occurring or laboratory cultivated micro-organisms to reduce or eliminate toxic pollutants. Petroleum products are a rich source of energy and some organisms are able to take advantage of this and use hydrocarbons as a source of food and energy. This results in the breakdown of these complex compounds into simpler forms such as carbon dioxide and water. Bioremediation thus involves detoxifying hazardous substances instead of merely transferring them from one medium to another. This process is less disruptive and can be carried out at the site which reduces the need of transporting these toxic materials to separate treatment sites.