ZEMO, DAWN A.
Geomatrix Consultants., San Francisco, CA

Abstract: Applications of Forensic Chemistry for Petroleum Cases

Forensic chemistry is useful for petroleum hydrocarbon investigations or litigation for three primary reasons: (1 petroleum products are chemically complex and can be highly variable in composition within certain performance-based ranges, (2) routine EPA analytical methods only generalize the nature of petroleum products and reflect little of the chemical detail needed for forensic purposes, and (3) crude oils and products weather in the environment and change in chemical composition over time. Forensic chemistry is frequently used to answer questions about the identification or age of petroleum in the subsurface.

The presentation will provide examples of multiple applications of forensic chemistry, including: gas chromatography pattern-matching for product identification, discriminating between weathered fuel oils based on families of aromatic hydrocarbons, determining whether polynuclear aromatic hydrocarbons are of petroleum or combustion origin, using key discrete constituent analysis (e.g., PIANO) to distinguish between products of similar type or boiling range, and age dating products using key additives.

The best forensic interpretations rely on multiple lines of evidence and must incorporate the effects of weathering, changing refinery and transportation practices, and avoid the pitfall of confusing weathering and age.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas