|Petroleomic Depth Profiling of Staten Island Soil by GC and FT-ICR MS
|Energy & the Environment
|Ms Mary Thomas
|University of Warwick
Abstract Information :
The New York/New Jersey Harbor (NY/NJ) Estuary is in a region with one of the
highest population densities in the United States, with many heavy waste generating
industries based in the area. Unsurprisingly, the NY/NJ Estuary was ranked among
the most chemically contaminated waterways in the United States based on surface
sediment concentrations. Elevated body burdens of toxic substances including heavy
metals, petroleum hydrocarbons, and aromatic hydrocarbons have also been
detected in a wide range of aquatic wildlife.
Environmental samples, particularly those contaminated with petroleum-related products, are highly complex. Using state-of-the-art analytical techniques, comprehensive molecular characterization of petroleum-related samples can be achieved. Following such analyses, unique fingerprints can be established for the samples, allowing any transmission into the environment to be traced. The characterization of petroleum-related samples using mass spectrometry has been termed 'petroleomics', with the molecular formulae of tens of thousands of components observed in a single spectrum.
In this study, soil was sampled at 5 depths in Staten Island, New York, with the aim of correlating the compositional fingerprints of the petroleum extracts with the history of the area. The extracts were profiled by a combination of gas chromatography (GC) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). GC provided a summary of the bulk properties of the extracts including total petroleum hydrocarbon (TPH), polycyclic aromatic hydrocarbon (PAH), and sediment toxicity (microtox) analyses. FT-ICR MS revealed more detailed compositional differences between organic contributions at different depths. The relative contribution from more highly oxygenated organic compounds was found to increase as the sampling depth increased. Changes in the contributions from sulfur-containing classes were also observed. Each individual component and its contribution can be visualised further in a plot of double bond equivalents against carbon number for each compound class.
The detailed molecular characterization obtained by FT-ICR MS coupled with the bulk information determined by GC allows a fingerprint of the petroleum-based contaminants of the soil to be developed. Petroleomic profiles of soil as a function of depth allow contamination to be correlated with the site history, and aging of petroleum-based compounds over time to be better understood.