T1 PM Contaminant Cycling Assessment and Prevention in the NY/NJ Harbor (Part 2)
Tuesday, 15 November 2005: 1:50 PM - 5:30 PM in Ballroom 1

(KRU-1117-835217) Molecular characterization of organic matter in Passaic River sediments.

Kruge, M¹, ¹ Earth & Environmental Studies Dept. and Passaic River Institute, Montclair State University, Montclair, NJ, USA

ABSTRACT- Contaminated Passaic River sediments (collected near river miles 3 and 7) were subjected to molecular organic analysis by pyrolysis-gas chromatography/mass spectrometry. Py-GC/MS offers a practical alternative for rapid, inexpensive analysis, simply employing milligram quantities of dry, disaggregated sediment. The compounds detected comprise an information-rich mixture of thermally extractable components and the products of the thermal decomposition of (bio)polymers present in the sample. These include polycyclic aromatic hydrocarbons (PAHs), petroleum biomarkers, organonitrogen compounds, and methoxyphenols. The presence of (thermally-desorbed) C₂₇ - C₃₃ hopanes and C₂₇ - C₂₉ steranes provides clear evidence for contamination by heavy petroleum fractions in most of the samples analyzed. n-Alkanes present are often the pyrolysis products of petroleum asphaltenes and biodegraded petroleum derivatives, with the superimposition of long chain, odd carbon number n-alkanes derived from leaf waxes. PAHs of two to six rings are readily detectable and the evident predominance of parent PAHs over their methylated counterparts suggests that fuel combustion products are the principal contributors, with ancillary contribution from petroleum products and coal tar varying in degree with location and depth of sample. Unusual sulfur compounds (C₂₀ isoprenoid thiophenes) are thermally extractable from many of the samples. Small, cyclic organonitrogen compounds (including pyrrole, pyridine, benzonitrile and indole) also occur in the pyrolyzates. These compounds are characteristic pyrolysis products of proteins and degraded proteinaceous matter, largely from aquatic algae and bacteria. In core samples from an apparently undredged site, deeper sediments are relatively enriched in these compounds, while sediments at the surface show a relatively larger terrestrial plant component, represented by the methoxyphenolic pyrolysis products of lignin. Thus, in addition to indicating the type and extent of organic pollution, Py-GC/MS data also provide information on sediment biogeochemistry and the environmental context.

Key words: organic matter, PAH, petroleum pollution, Passaic River