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ASSESSING THE PHYTO-REMEDIATION OF AGED PETROLEUM HYDROCARBONS IN CON-TAMINATED SOIL BY GAS CHROMATOGRAPHY/MASS SPECTROMETRY

Although monitoring the compositional changes of petroleum hydrocarbons is crucial in evaluating remediatlon rates, accurately quantifying bioremediation of aged petroleum hydrocarbons in soil is sometimes a difficult task because of sample heterogeneity and background interferences. Some of these problems can be overcome by analyzing for naturallyoccurring, recalcitrant compounds (called biomarkers) and normalizing the data with respect to biomarker concentrations and distribution.

Assuming that the biomarkers degrade at a much slower rate than that the rest of the contaminant matrix, this method will account for heterogeneity and most sources of non-biological degradation. In our study, aged petroleum-contaminated soil from a phytoremediation site was used.

Soil was extracted and fractionated into different classes of hydrocarbons using column chromatrography, and target compounds were identified and quantified by gas chromatography/mass spectrometry. The average initial concentrations of contaminants were 2.95 mg/kg for hopane, 0.24 mg/kg for benzo(a)pyrene, and 0.29 mg/kg for benzanthracence. The concentrations of these target compounds will be measured again after one year of plant growth.

The phytoremediation efficiency will be evaluated by comparing PAH degradation in the presence of different plant species to that in the absence of plants.

Key words: hydrocarbons, phytoremediation, gas chromatography, mass spectrometry, PAH