Polycyclic Aromatic Hydrocarbons: Toxic Effects and Their Bioremediation Strategies

Polycyclic aromatic hydrocarbons (PAHs) are the ubiquitous recalcitrant organic compounds containing two or more fused benzene rings in their structure. PAHs are released into the environment due to incomplete combustion of fossils, petrochemical industries, forest fires, volcanic eruptions, creosote, etc. They are highly persistent and recalcitrant due to their hydrophobic nature and lower aqueous solubility than the monoaromatics. PAHs are mutagenic, carcinogenic in nature, and considered as priority pollutants. Large numbers of PAHs in soil are taken up by plants and enter our food chain, thereby causing serious health problems. Thus, removal of these toxic compounds is the need of hour for which microbial bioremediation has turned out as a pivotal process. Bioremediation using microbiota is considered as an environmentally benign and effective remediation strategy to remove these PAH pollutants from the environment. Moreover, this technology needs further attention from the research community to make it successful and economical to be used in cleaning and restoration of the sites contaminated with persistent pollutants.