Role of microorganisms in remediation of contaminated soil

Starting from the mining of raw materials to production, transportation, use by end users, disposal or accidental spills of chemicals often contaminate soil to the extent that threaten the health of human life, livestock, wildlife and indeed whole ecosystems. Traditional methods to cleanup or decontaminate the soil are expensive, labour intensive, do not always ensure that pollutants are completely removed or destroyed and often result in abrupt changes to the physical, chemical, and biological characteristics of the treated soil. Use of microorganism have shown promises in remediation of soil contaminated with heavy metals and radionuclide, organic compounds including chlorinated solvents like TCE; explosives such as TNT, RDX; petroleum hydrocarbons including PAHs; PCBs and pesticides such as atrazine and organophosphates. Aesthetically pleasing cleaning methodology, minimal disruption and preservation of top soil, usefulness in treating broad range of environmental contaminants and low cost (60-80% or even less costly than conventional methods) are the advantages associated with microorganisms mediated soil remediation technology and so it has gained increasing attention over the past 15 years. The review focuses on an overview of various physico-chemical methods used earlier for soil remediation purposes, what are the bioremediation techniques used nowadays and how it works; finally future perspectives of bioremediation techniques and conclusion.