Comparison of polycyclic aromatic hydrocarbon distributions and sedimentary organic matter characteristics in contaminated, coastal sediments from Pensacola Bay, Florida

Myrna J. Simpson, Benny Chefetz, Ashish P. Deshmukh, Patrick G. Hatcher*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

In this study, we examined the distribution of polycyclic aromatic hydrocarbons (PAHs) in a contaminated coastal area and the characteristics of the natural organic matter in tandem. We present a detailed study of PAH concentration, distribution, and organic matter characteristics of three core samples from Pensacola Bay, Florida. Solid-state 13C Nuclear Magnetic Resonance (NMR), pyrolysis gas chromatography coupled with mass spectrometry (GC-MS), and tetramethyl ammonium hydroxide (TMAH) thermochemolysis GC-MS were applied to obtain structural details about the sedimentary organic matter. Elemental compositions (carbon and nitrogen) and estimates of black carbon contents are also reported. These coastal sediments were found to contain more PAHs in the upper 15 cm layers than in the bottom 15-25 cm samples. The samples that contained the most PAHs also contained the least amount of aromatic carbon and contained a significant amount of paraffinic carbon. Lignin-derived pyrolysis and TMAH thermochemolysis products were abundant and generally higher in all of the samples in comparison to those reported for modern coastal sediments, indicating a large flux of terrestrial carbon. The black carbon contents were found to range from 4.3% to 6.8%, which are significantly lower than other reports of black carbon in sediments, which represent as much as 65% of the total organic carbon content. The low black carbon content suggests that this type of refractory carbon may not be as responsible for regulating PAH distribution as indicated by other researchers.

Original languageAmerican English
Pages (from-to)139-163
Number of pages25
JournalMarine Environmental Research
Volume59
Issue number2
DOIs
StatePublished - Mar 2005

Bibliographical note

Funding Information:
The Natural Science and Engineering Research Council (NSERC) of Canada is gratefully acknowledged for granting a postdoctoral fellowship to M.J.S. The National Science Foundation – Environmental Molecular Science Institute (CHE-0089147) and the Office of Naval Research (ONR-Grant no. N00014-99-1-0073) – provided financial support for this research. We also thank Dr. Elizabeth Guthrie-Nichols for assistance during sample collection.

Keywords

  • Black carbon
  • Pyrolysis GC-MS
  • Sedimentary organic matter
  • Solid-state C NMR
  • TMAH thermochemolysis GC-MS

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