Recent advances in quantification and remediation technologies for toxic PAH mitigation from the environment

Polycyclic aromatic hydrocarbons (PAHs) are a type of organic compounds consisting of at least two or more fused aromatic rings. PAHs are frequently found in the environment and are mainly produced as a consequence of anthropogenic activities. These compounds are very toxic (carcinogenic) to living organisms and the environment. Their hydrophobicity and high photochemical stability make them very difficult to degrade or remove from the environment. This makes PAHs persistent organic pollutants (POPs). Significant research has already been devoted to developing a range of PAH remediation technologies. Several methods based on the physical, chemical, and biological transformation of PAHs are reported. Some of these are promising, while some are still at the developmental stage. The recently employed mechanochemical approach is also getting more attention. Here, we provide a brief account of the nature of PAHs, their sources, environmental impact, the problems associated with their remediation, and recent progress in the remediation technologies like membrane filtration, soil washing, thermal and photochemical degradation, microbial remediation, and mechanochemical degradation. The advantages, limitations, and future outlook of these methodologies are also addressed.