Assessment and documentation of bacterial diversity at sites contaminated with petroleum hydrocarbons: A polyphasic approach

Petroleum hydrocarbons are a major source of energy, providing over 50% of the energy used all over the world. In addition, petroleum is the principal source of lubricants, solvents and a variety of large volume chemical feedstock for synthesis of plastics, fibers, detergents, pharmaceuticals and cosmetics. A vast scale of operation necessitated by the above demands renders the petroleum industry a potential source of air, water and soil pollution. Petroleum as crude oil while drilling, refinery effluents, slop oil emulsion solids and as water from ballast tanks may find its way into the adjoining land and surface or ground water through accidental or deliberate disposal. In India petroleum exploration has been in operation for over 100 years. Crude oil was first struck in Digboi, located at the northeastern past of India in the later part of 18th century. Since then, expansion of oil exploration, refining processes, and transportation of crude oil and finished petroleum products has been carried out through a massive pipeline network. Crude oil and petroleum product spills during oil exploration, refining and transportation are very common in India. Many farmers have lost their agricultural land due to oil spills in their fields. Many fishermen in India have lost their livelihood due to oil slick in lakes and rivers. Currently, India has 18 oil refineries in the public and private sectors, with a gross refining capacity of over 112 million tonnes. Petroleum industry by-products have a detrimental effects on the environment which is evident from their classification as new waste categories (Waste category number 10 and 12) under the recent Hazardous Waste act of 1998 (Government of India).