Identification of Petroleum Residue Sources After a Fire and Oil Spill

Abstract

The evaluation of the environmental impacts resulting from an oil spill and fire at the West Hackberry Strategic Petroleum Reserve Complex was particularly challenging. The fire and spill resulted in two distinctive types of chemical releases into the environment. The spill released a large quantity of Arabian light crude oil into an area that had been exposed to Louisiana sweet crude oil during 40 years of production. The fire produced significant quantities of pyrogenic polycyclic aromatic hydrocarbons that were dispersed over a large area by wind. New methods were developed to identify samples, and consequently the areas, that were affected by these releases. Samples of sediment affected by the oil spill were distinguished from nonaffected samples by comparing the ratios of the alkyl phenanthrenes to the alkyl dibenzothiophenes (C1, C2, and C3) in a gas chromatography–mass spectrometry analysis of the extractable hydrocarbons. These ratios effectively identified affected sediment even when the samples had been exposed to the environment for more than a year. Contamination from the pyrogenic products of the fire was identified by the elevated quantities of fluoranthene and pyrene in affected samples. Foliage, soil, and sediment samples were collected quarterly for the year following the incident and were analyzed by the combined gas chromatography-mass spectrometry method. Impact from the fire was detected in foliage and soil samples collected several miles downwind from the incident.

Organic geochemistry indicates Gebel El Zeit, Gulf of Suez, is a source of bitumen used in some Egyptian mummies

“…These ratios, which vary among oils having the different sulfur contents, were previously shown to remain relatively constant as oil weathers (Overton et al, 1981), and prove useful in distinguishing and correlating hydrocarbon inputs to heavily weathered oil residues (Boehm et al, 1983). Results in Table I show that the oil seep samples displayed little changes in the ratios of C2-DBTs/C2-PHENs (0.41 and 0.36) and C3-DBTs/C3-PHENs (0.47 for both oil seeps), indicating a common source.…”

“…The chromatograms in Figures 2c and 2d show much lower n-alkane concentrations and higher pristane and phytane concentrations on top of a large UCM, resulting in significant increase in the ratios of UCM/TRP (the ratio of the concentrations of unresolved complex mixture to total resolved peaks), Pr/n-C 17 , and Ph/n-C 18 , providing evidence for a higher degree of weathering and biodegradation. Pr/n-C 17 , Ph/n-C 18 , UCM/TRP indices, and the weathering ratios (WR), defined as the ratio of ⌺ (n-C 23-34 )/⌺ (n-C 11-22 ) (Kennicutt, 1988), are higher in Oil Seep-1 than in Oil Seep-2, indicating that the former oil is degraded to a much higher extent (Overton et al, 1981;Kennicutt, 1988;Didyk and Simoneit, 1989). The more advanced weathering of Oil Seep-1 is further indicated by the lower value of the ALKs/PAHs ratio (0.39), as compared to that of Oil Seep-2 (1.40).…”

“…In several studies in which the source of crude oil requires identification, the relative abundance of the PAH alkyl homologue ratios, C 2 -dibenzothiophenes/C 2 -phenantherenes (C2-DBTs/C2-PHENs), and C 3 -dibenzothiophenes/C 3 -phenantherenes (C3-DBTs/C3-PHENs) were used as diagnostic source parameters (Page et al, 1995). These ratios, which vary among oils having the different sulfur contents, were previously shown to remain relatively constant as oil weathers (Overton et al, 1981), and prove useful in distinguishing and correlating hydrocarbon inputs to heavily weathered oil residues (Boehm et al, 1983). Results in Table I show that the oil seep samples displayed little changes in the ratios of C2-DBTs/C2-PHENs (0.41 and 0.36) and C3-DBTs/C3-PHENs (0.47 for both oil seeps), indicating a common source.…”

The natural petroleum hydrocarbon background in subtidal sediments of prince william sound, Alaska, USA

“…Petroleum from different sources can have very different PAH distributions. The relative abundances of the alkyl homologues of phenanthrene relative to that of dibenzothiophene have been used to diagnose different petroleum sources [2,42]. As shown below, an important natural source of petroleum hydrocarbons in Prince William Sound subtidal sediments is seep-derived petroleum imported on suspended sediment from the eastern Gulf of Alaska.…”

Oil source-fingerprinting in support of polarimetric radar mapping of Macondo-252 oil in Gulf Coast marshes

“…The C 2 and C 3 alkyl homolog ratios provide evidence of MC-252 oil in addition to the biomarker ratios for source identification of Louisiana Sweet Crude oils and have been extensively used as source specific markers of oil in sediments (Overton et al, 1981;Wang et al, 1994). Samples initially categorized as probable match or inconclusive could be reclassified into the match category only if they met the following conditions: DBTs/Phens ratios were within ±5% of the MC-252 DBTs/Phens ratios; and, they exhibited a qualitative positive match to MC-252 oil.…”