Abstract:
The partitioning interwell tracer test (PITT) has been demonstrated to be effective in
determining volume and spatial distribution of residual nonaqueous phase liquids (NAPLs)
in the saturated subsurface. Use of PITT technology in the vadose zone has been limited
to this point. Two PITTs were completed in the vadose zone of a NAPL contaminated site
at Kirtland Air Force Base in Albuquerque, NM. The PITTs were completed before and after
a thermally enhanced soil vapor extraction remediation effort, to provice performance
assessment. Methane was used as a nonpartitioning tracer. Four perfluorocarbons
(perfluoromethylcyclohexane, perfluoro-1,30dimethylcyclohexane,
perfluoro-1,3,5-trimethylcyclohexane, and perfluorodecalin) were utilized as air-NAPL
partitioning tracers. Difluoromethane was used as an air-wter partitioning tracer to
estimate water saturation. The complex light NAPL (LNAPL) consisted of hydrocarbon fuels
ranging from approximately 12-70 carbons in size. Laboratory experimental data and
thermodynamic modeling were used to characterize compositional changes in the NAPL due to
the remediation effort. About 260 kg of NAPL were removed from the subsurface by the
remediation effort. The PITT assessment of the remediation was compared favorably to the
results from soil borings taken at the site. The PITT has been shown to be a useful
technology for both NAPL characterization and remedial performance assessment in the
vadose zone.
Reference:
N.E. Deeds, G.A. Pope and D.C. McKinney, "Vadose Zone Characterization at a Contaminated
Field Site Using Partitioning Interwell Tracer Technology," Environmental Science &
Technology, 33 (16), 2745-2751, 1999.
Back to Gary Pope's publications page
Last updated: May 2, 2002