Bioavailability of Residual PAHs in Creosote-Contaminated Soil Following Pilot-Scale Bioremediation(Abstract)

摘要

An enhanced natural attenuation (ENA) technique was previously applied at pilot scale for the remediation of a creosote-contaminated soil. Following six months of treat- ment, the total PAH concentration in the creosote-contaminated soil was reduced from 7767 ± 1286 mg kg-1 to 2250 ± 71 mg kg-1, with 82-99% and 33-81% removal of three- and four-ring PAHs respectively. The high residual concentration of some four-ring PAHs at the end of the treatment period was attributable to bioavailability issues rather than a lack of microbial catabolic activity while residual five-ring compounds was attrib- utable to their recalcitrance to microbial degradation. Often bioremediation endpoints may not be reached due to bioavailability limitations resulting in a reduction in degrada- tion efficacy. Further biological treatment of the creosote-contaminated soil did not result in further removal of PAHs. In order to determine the impact of the residual PAH fraction following enhanced natural attenuation, both toxicity and bioavailability studies were undertaken. Conceivably, the bioavailability limitations observed in the biodegradation treatments may also result in a reduction in the effective contaminant concentration which may impact on ecological receptors.