Phytoremediation of polycyclic aromatic hydrocarbons (PAHs) in urban atmospheric deposition using bio-retention systems

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds in urban environment and pose a great concern in environmental pollution due to their carcinogenicity. The inefficient fuel combustion is the major cause for the emission of PAHs in urban atmosphere. The emitted PAHs are either in particulate or in vapor phase however finally end up with deposition and directed into water reservoirs or groundwater table via storm water. Instead of conventional techniques such as solvent extraction, chemical oxidation, photocatalytic degradation, electrokinetic remediation, and thermal technologies, bio-retention systems can be used to remediate PAHs in storm water. However, bio-retention system does not facilitate the degradation or removal of PAHs, instead it facilitates the accumulation of PAHs in the soil. The use of phytoremediation in bio-retention systems is a hybrid technology that can provide efficient PAH removal by cutting down the biochemical cycling of PAHs. Although phytoremediation and bio-retentions systems are well-established technologies, their combination is rarely used. This chapter discusses the possibility of the use of phytoremediation in bio-retention systems, for remediation of deposited PAHs in the urban environment. Bio-retention systems with phytoremediation not only remediate PAHs but also reduce other pollutants such as heavy metals, nutrients, enhance the esthetic value, and create opportunities to produce biomass for bio-fuel production.