Shows Promise for Decontaminating Groundwater
By David Elstein
April 9, 2002
Trichloroethylene (TCE), a colorless,
toxic liquid widely used as a solvent for dry cleaning and degreasing, has been
known to seep into groundwater and make it dangerous for consumption. TCE also
has been found in groundwater on some military bases. Now
Agricultural Research Service scientists
may have found an inexpensive but effective product to clean up the mess:
Microbiologist Jim Hunter of the ARS Soil-Plant-Nutrient Research Laboratory,
Ft. Collins, Colo., has discovered that vegetable oil can be used to clean up
groundwater contaminated with TCE. He recommends using soybean oil since it is
Battelle, a nonprofit scientific company, originally suggested that
vegetable oil may clean up pollutants in groundwater, and Hunter was able to
prove it. Hunter also has shown that vegetable oil can clean up groundwater
that is contaminated with nitrogen fertilizer and the herbicide chlorate.
Hunter believes the best way to get the oil into the water is by injecting
the oil into the ground as an emulsion using high pressure to create a porous,
oil-containing barrier across the contaminated aquifer. The oil, used in low
concentrations, stimulates microorganisms naturally present in the aquifer to
grow and accumulate in the barrier. The TCE is degraded by these microorganisms
as contaminated groundwater flows through the barrier.
Parsons Corporation, an environmental consulting firm in Denver, Colo., is
using this ARS method to cleanse TCE from groundwater. Parsons is halfway
through its tests on several Air Force and Navy bases to see how effective the
vegetable oil is. The company has already completed some pilot tests and is now
working on full-scale evaluations.
ARS is the U.S. Department of
Agricultures primary scientific research agency.