Quantification of petrogenic PAH in marine sediment using molecular stable carbon isotopic ratio measurement

Abstract

Compound-specific carbon isotope analyses were performed on polycyclic aromatic hydrocarbons (phenanthrene and methylphenanthrenes) isolated from marine sediments contaminated with petroleum. Isotopic composition measurements of individual methylphenanthrenes were subject to important uncertainties because they were not completely separated by gas chromatographic separation. Nevertheless the isotopic composition of the sum of methylphenanthrenes was measured with good reproducibility. As petrogenic PAHs and PAHs present in the sediment before the petroleum contamination have different isotopic compositions it was possible to quantitatively source apportion methylphenanthrenes in contaminated sediment with a good precision and reliability, using the isotopic composition of the sum of methylphenanthrenes and a simple mass balance calculation.