Polycyclic aromatic hydrocarbons (PAHs) are among the more resistant compounds found in petroleum contaminated soils and persist even after extensive bioremediation. Phytoremediation has been demonstrated to enhance the degradation of PAHs, but the mechanisms of dissipation have not been identified. The degradation of pyrene and anthracene was investigated in a laboratory study in which soil was removed from the rhizosphere of a long-term stand of alfalfa and compared to degradation in non-rhizosphere and sterile soil. Low molecular weight organic acids typically found in the rhizosphere were added to the soils to determine if exudation of simple organic compounds may be part of the rhizosphere effect. Dissipation in non-sterile soils was found to be much greater than in sterile soil, but there was no rhizosphere effect and the addition of organic acids did not enhance degradation. The effect of the rhizosphere on PAH degradation seems to be short-lived and requires the continued presence of roots.
ASJC Scopus subject areas
- Chemical Engineering(all)