Aged Petroleum-contaminated Soil Restoration and Benzo[a]pyrene Biodegradation

Abstract

A laboratory study was conducted to enhance the bioremediation rate of aged petroleum-contaminated soil by anaerobic biodegradation and natural attenuation. Extracted contaminants during soil treatment were fractionized and analyzed using gas chromatography-mass spectrometry and Fourier transform ion cyclotron resonance mass spectrometry. A significant biodegradation was achieved after a 160-day treatment. The loss of total petroleum hydrocarbons (TPH) was 73.6% with an initial TPH content of 2,985 mg kg⁻¹. The losses of saturated and aromatic fractions were 84.7% and 80.9%, respectively, with the polar compounds becoming the dominant component in the residual pollutants. It was observed that naphthalene with a substituent groups can be easily attacked and biodegraded by microbes than that with SS substituent groups. The benzo[a]pyrene (BaP) concentration was decreased considerably in the presence of benzo[e]pyrene (BeP) during biotreatment. It was proposed that BaP may be biotransformed to BeP by cometabolism, which can be further biodegraded to avoid the damage to microbes caused by the toxicity of BaP.

Keywords:

• benzo[a]pyrene
• biodegradation
• cometabolism petroleum-contaminated soil
• polycyclic aromatic hydrocarbons