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U.S. Department of Energy
Office of Scientific and Technical Information

Forensic determination of source of methane associated with a major gasoline spill

Conference ·
OSTI ID:569973
 [1];  [2];  [3]
  1. Unocal Corp., Brea, CA (United States)
  2. Entrix, Inc., Walnut Creek, CA (United States)
  3. Unocal Corp., Seattle, WA (United States)
Hydrocarbon vapors associated with spilled petroleum products can arouse regulatory concern and pose a significant health risk. Identifying the source and origin of these vapors is an important part of evaluating potential exposure pathways, selecting appropriate remedial measures, and determining environmental liability. While gasoline does not contain a significant amount of methane, high methane contents in soil gas near petroleum spills have been reported. This correlation has led some environmental scientists to infer a direct causal relationship between petroleum contamination and soil gas methane. An investigation of the distribution and origin of soil gas methane was conducted at the location of a major gasoline spill in an urban area. Approximately 80,000 gallons of gasoline was released at the site in 1980. Recovery wells and trenches subsequently recovered over 40,000 gallons of liquid phase gasoline between 1980 and 1983. In 1988, a soil vapor extraction system (SVE) was installed to recover additional gasoline and to control hazards associated with combustible vapors. During routine monitoring of the SVE system, methane was observed to comprise a significant component of the influent vapor stream. The methane was originally interpreted to have formed by bacterial degradation of the spilled gasoline. However, the persistence of the methane over time raised new questions about its origin and lead to the current investigation.
OSTI ID:
569973
Report Number(s):
CONF-971116--
Country of Publication:
United States
Language:
English