Geochemical Services

Dry Cleaner Investigation Reveals Unknown Source


The GORE® Survey not only confirmed the PCE source area at the dry cleaner site (fig. 1),

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but also identified a formerly unknown source of TCE at an abandoned septic site (fig. 2).

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Site Background & Geology

Location: Southwest US (Arizona)
Property: Dry cleaner
Soil: Shallow soils and fractured granite(surface to depth); low organic content
Groundwater: 90 ft
History:

  • Former residential site converted to commercial
  • Known heavy PCE usage as early as 1995
  • 1997: PCE detected in drinking water wells nearby
  • 1998: Video inspection of sewer line; soil samples and soil gas samples collected; inconclusive results
  • 2000: GORE® Survey to delineate source and extent of groundwater contamination

GORE® Survey

  • 55 GORE® Modules
  • Avg. 25 ft. grid sample spacing
  • Focus in and around dry cleaner, adjacent parking lot and along sewer lines in nearby streets
  • Modules installed beneath asphalt, building slab and in sewer trenches
  • 3-ft. install depth
  • 10 - 14 day exposure
  • Modified EPA method 8260/8270 GC/MS analysis at Gore labs

Survey Results

  • Suspected PCE source area at dry cleaner site confirmed
  • Previously unidentified source of TCE found, identified as abandoned septic system remaining from residential use of property
  • Later noted that TCE was commonly used to flush septic system
  • GORE® Survey identified TCE source area for inclusion in remediation plan
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