The Relationship between Polycyclic Aromatic Hydrocarbons and Heavy Metals

Background: Heavy metals and PAHs in flue gas have received considerable attention in recent years due to their mutagenic or carcinogenic properties. PAHs are products of incomplete combustion of carbonaceous compounds at high temperatures. Heavy metals are released into the ambient air from the same sources as those earlier mentioned for PAHs. The present study was carried out to investigate the influence of the quantity of heavy metals on PAHs formation in ambient air. Methods: In this study, air particulates were collected on glass fiber filters using a high- volume air sampler. Each filter was exactly cut into equal pieces. One piece was digested with HNO3 as well as H2O2 and used for determination of heavy metals. Another piece was extracted using Soxhlet method. The latter was used for the determination of PAHs. The concentrations of heavy metals (Cr, Cd, Cu, Pb, and Zn) were measured using Perkin- Elmer atomic absorption spectrometer. The concentration of PAHs was measured by a PU4400 gas chromatograph equipped with FID detector. The concentrations of PAHs and heavy metals were determined in different seasons. Results: The results showed that the concentration of PAHs was minimum in the weekend and holidays, but maximum in winter. The relationship between ambient air concentrations of PAHs and heavy metals was investigated and an excellent agreement was found. The general trend of variations in concentration of heavy metals were found very similar to PAHs, therefore it could be concluded that the source of pollution was the same for both of pollutants. Conclusion: The general trend of variations in concentration of heavy metals was found very similar to PAHs, therefore it could be concluded that the source of pollution was the same for both of pollutants.