Soil contaminated with PAHs and nitro-PAHs: contamination levels in an urban area of Catania (Sicily, southern Italy) and experimental results from simulated decontamination treatment

This study is aimed at investigating the levels of polyaromatic hydrocarbons and nitro-polyaromatic hydrocarbons in polluted urban soils and the potential application of microwave heating as decontamination treatment. The soil samples were collected from an area of 0.05 km² of Catania (Sicily, southern Italy) rural site. HPLC in fluorescence and electrochemical–fluorescence detection mode were used for selective separation, identification and quantification of pollutants in soil samples. A bench-scale microwave treatment was performed irradiating a contaminated soil using different operating powers for removing both kinds of contaminants. Results reveal that soil pollutant concentrations were sometimes higher than those found in other locations. Polyaromatic and nitro-polyaromatic hydrocarbon levels observed suggest a strong contribution from incomplete combustion of gasoline or other fuels also due to the vicinity to the airport. Many polyaromatic hydrocarbon derivatives are more carcinogenic than the initial contaminant form and may have toxicological significance, even if present at much lower concentrations than their parent compounds. Thus, the environmental levels of these pollutants need to be monitored and removed. Contaminant removals from simulated microwave remediation show that the treatment is effective. Results also showed that contaminant features, especially polarity, significantly influence the dielectric properties of the soil and thus the final temperature reachable during the heating processes and the contaminant removals.