Development of Naphthalene Catabolism in Al and Fe contaminated soil

Metals have the potential to affect the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in mixed contaminated soils. This investigation considered the effects of Al and Fe (50, 100, 250 and 500 mg/kg) on ¹⁴C-naphthalene biodegradation in soil over 63 d contact time. The presence of Al at low concentrations (50 and 100 mg/kg) stimulated (p < 0.05) naphthalene biodegradation in fresh Al amendments; however, naphthalene mineralisation was significantly reduced (p < 0.05) in 500 mg/kg aged Al amendment, but this reduction only occurred at 1 and 21 d in 500 mg/kg fresh Al. Naphthalene mineralisation was stimulated (p < 0.05) in the highest Fe concentration (500 mg/kg) in both aged and fresh Fe amendments at 42 d. This suggests that Al has a greater impact than Fe on the development of PAH catabolism in soil. Studies on metal-PAH impact in soil facilitates the assessment of risk, hazard and bioremediation potential at sites contaminated with both contaminants.