Vermiremediation - Remediation of Soil Contaminated with Oil Using Earthworm (Eisenia fetida)

Vermiremediation is considered as an evolving environmental friendly and sustainable technology. It serves as an additional parallel factor in increasing overall efficiency of bio-methods. Vermiremediation treat soils contaminated with inorganic and organic chemicals through different direct actions like bioaccumulation of chemical contaminants and indirect action like using vermicast of earthworm to bioadsorb the chemical contaminants etc. Vermiremediation excels other bio-conversion technologies since the organics such as PAHs and TPH that otherwise cannot be utilized by others, can be utilized by this technology. This includes about 100-1000 times greater value enhancement as compared to other biological technologies. Limitations of vermiremediation include, earthworms' applicability only to less toxic soil, and to the certain depths (epigeic (0.1-0.3 m), anecic (3 m), endogeic (0.2 m)) of the soil, sensitive to any change in environmental conditions etc. This review is aimed to provide the summary of previous investigations showing the potential of Eisenia fetida an earthworm species in remediating the oil-contaminated soil. Several lab experiments have been conducted in this regard. Potentials and limitations of earthworms particularly Eisenia fetida and strategies to overcome those limitations have been discussed. It is recommended that in the future further studies are required, to comprehend the processes involved in vermiremediation and to evaluate the potential side effects of the measurements taken to enhance the vermiremediation process. Moreover, understanding organic contaminants behavior in drilosphere, methods for collecting earthworm in the contaminated soil and their disposal after harvesting is also needed.