Bioavailability Prediction of Polycyclic Aromatic Hydrocarbons in Field-Contaminated Sediment by Mild Extractions

Assessing the bioavailability of a group of polycyclic aromatic hydrocarbons (PAHs) coexisting in a field-aged contaminated sediment was examined using mild extractions by isopropanol- and ethanol-water solutions at concentrations of 5–100%, using extraction durations from 1 h to 7 days. At a given solvent concentration, an initial rapid phase of PAH desorption was generally observed during the first 12 h, followed by a subsequent slower phase of desorption. A similar biphasic desorption was evident with increases in solvent concentration. PAH removal by various mild extractions was compared with PAH biodegradation by indigenous microorganisms. The removal of individual PAHs using 1-day 70% ethanol extraction was closely correlated to corresponding PAH removal via biodegradation, suggesting the possibility of using alcohol-water solution to simultaneously predict the bioavailability of multiple PAHs in aged sediments to indigenous microorganisms.