Strategies for Remediation of Polycyclic Aromatic Hydrocarbons from Contaminated Soil-an Overview

Polycyclic aromatic hydrocarbons (PAHs) are one of the most prevalent contaminants having toxicity, mutagenecity and carcinogenicity. Pollution caused by PAHs is a serious problem throughout the world. To solve the problem, substantial research efforts have been directed worldwide to adopt sustainable technologies for the treatment of PAHs containing soil. PAH compounds are transferred, degraded and sequestered in soils. They are relocated in the environment through volatilization, adsorption, leaching and erosion without alteration in their structure. Degradation causes alteration of PAHs structures from their original form though biological and chemical processes and sequestration occurs when PAHs are removed from bioavailable pools and stored for a long period of time. The conventional techniques for PAH removal involve excavation of contaminated soil and its incineration which are quite expensive and in many cases pollutants are transferred from one phase to another. The commonly employed biological methods for PAHs remediation in soil are landfarming, composting, bioaugmentation, biostimulation, phytoremediation etc. and chemical methods include photooxidation, ozone treatment, Fenton processes etc. This article critically reviews the updated information on various strategies implemented for remediation of PAHs from soil which will provide insights into this research frontier.