USE OF HOPANE AS A CONSERVATIVE BIOMARKER FOR MONITORING THE BIOREMEDIATION EFFECTIVENESS OF CRUDE-OIL CONTAMINATING A SANDY BEACH

Much of the variability inherent in crude oil bioremediation field stu dies can be eliminated by normalizing analyte concentrations to the co ncentration of a nonbiodegradable biomarker such as hopane. This was d emonstrated with data from a field study in which crude oil was intent ionally released onto experimental plots on the Delaware shoreline. Fi ve independent replicates of three treatments were examined: no nutrie nt addition, addition of inorganic mineral nutrients alone, and nutrie nt addition plus indigenous oil-degrading microorganisms from the site . Samples collected biweekly were analyzed for the Most Probable Numbe rs (MPNs) of alkane and aromatic degraders and oil component analysis by GC/MS. The data were normalized to either the mass of sand that was extracted or to the concentration of hopane that was measured, Hopane normalization enabled detection of significant treatment differences in hydrocarbon biodegradation that were not detected when the data wer e normalized to sand mass. First-order loss rates for the hopane-norma lized data were lower than those for the sand-normalized data because hopane normalization accounts only for loss due to biodegradation wher eas sand normalization includes all loss mechanisms. Plots amended wit h nutrients alone and nutrients plus the inoculum showed enhanced remo val of hydrocarbons compared to unamended control plots. However, no d ifferences were detected between the nutrient-amended plots and the nu trient/inoculum-amended plots.