Effects of humic substances and soya lecithin on the aerobic bioremediation of a soil historically contaminated by polycyclic aromatic hydrocarbons (PAHs)
Article first published online: 25 SEP 2004
Copyright © 2004 Wiley Periodicals, Inc.
Biotechnology and Bioengineering
Volume 88, Issue 2, pages 214–223, 20 October 2004
How to Cite
Fava, F., Berselli, S., Conte, P., Piccolo, A. and Marchetti, L. (2004), Effects of humic substances and soya lecithin on the aerobic bioremediation of a soil historically contaminated by polycyclic aromatic hydrocarbons (PAHs). Biotechnol. Bioeng., 88: 214–223. doi: 10.1002/bit.20225
- Issue published online: 25 SEP 2004
- Article first published online: 25 SEP 2004
- Manuscript Accepted: 10 JUN 2004
- Manuscript Received: 13 FEB 2003
- humic substances;
- soya lecithin;
- polycyclic aromatic hydrocarbons;
- contaminated soils;
The high hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) strongly reduces their bioavailability in aged contaminated soils, thus limiting their bioremediation. The biodegradation of PAHs in soils can be enhanced by employing surface-active agents. However, chemical surfactants are often recalcitrant and exert toxic effects in the amended soils. The effects of two biogenic materials as pollutant-mobilizing agents on the aerobic bioremediation of an aged-contaminated soil were investigated here. A soil historically contaminated by about 13 g kg−1 of a large variety of PAHs, was amended with soya lecithin (SL) or humic substances (HS) at 1.5% w/w and incubated in aerobic solid-phase and slurry-phase reactors for 150 days. A slow and only partial biodegradation of low-molecular weight PAHs, along with a moderate depletion of the initial soil ecotoxicity, was observed in the control reactors. The overall removal of PAHs in the presence of SL or HS was faster and more extensive and accompanied by a larger soil detoxification, especially under slurry-phase conditions. The SL and HS could be metabolized by soil aerobic microorganisms and enhanced the occurrence of both soil PAHs and indigenous aerobic PAH-degrading bacteria in the reactor water phase. These results indicate that SL and HS are biodegradable and efficiently enhance PAH bioavailability in soil. These natural surfactants significantly intensified the aerobic bioremediation of a historically PAH-contaminated soil under treatment conditions similar to those commonly employed in large-scale soil bioremediation. © 2004 Wiley Periodicals, Inc.