Bioremediation of Polychlorinated Biphenyls- Impact on Ecosystem and Biodegradation Pathways

Polychlorinated biphenyls (PCBs) are a group of chlorinated aromatic compounds found in nature as byproduct of several industrial reactions. They are persistent organic pollutants, sparingly water soluble and can be found far away from point source of pollution. They are a great nuisance to the environment and ecosystem. Chemically they are hydrophobic in nature with severe toxicity and high bioaccumulation rate. They have varied congeners which depends on the number and position of the chlorine atoms in the aromatic ring. Usually the high molecular weight congeners pose real threat to soil and biotic life associated with it as they are recalcitrant over the low molecular weight compounds. Inspite of the restricted usage, their presence is sensed as a byproduct of certain chemical reactions of anthropogenic origin. Excessive exposure of humans to PCBs, impairs the immune system. They have negative impact on agricultural land like loss of soil health, soil microbes and soil protein. Moreover they gain entry into the food chain and being highly hydrophobic accumulate in the lipid biomass. Bioremediation strategies are designed and formulated to circumvent their effect from the ecosystem. In this review an attempt has been made to discuss on the impact of PCBs on ecosystem, its bioremediation trail and mitigation solutions.