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Prediction of Petroleum Hydrocarbon Bioavailability in Contaminated Soils and Sediments

Recently, several laboratory methods have been developed for the prediction of contaminant bioavailability. So far, none of these methods has been extensively tested for petroleum hydrocarbons. In the present study we investigated solid-phase extraction and persulfate oxidation for the prediction of total petroleum hydrocarbon (TPH) bioavailability. One sediment and two soil samples were subjected to solid-phase extraction, persulfate oxidation, and biodegradation, after which hydrocarbon removal was compared. It was demonstrated that a short solid-phase extraction (168 h) provided a good method for the prediction of the extent of TPH degradation in an optimized slurry reactor (84 d). Solid-phase extraction slightly underestimated the degradation of readily biodegradable hydrocarbons, whereas it slightly overestimated the degradation of poorly biodegradable hydrocarbons. Persulfate oxidation appeared to be unfit for the prediction of TPH bioavailability as persulfate was unable to oxidize hydrocarbons with a high ionization potential. Hydrocarbons that were affected were likely to be transformed rather than completely oxidized. Nevertheless, persulfate oxidation provided a good method for the prediction of polycyclic aromatic hydrocarbon (PAH) bioavailability.