The analysis suggests that the extraction wells and the pump-and-treat strategy are performing as expected, said Diane Agnew, a New Mexico Environment Department hydrologist.
About 50 people attended the Thursday meeting at the African American Performing Arts Center on the New Mexico Expo grounds.
The “plume-capture analysis” showed that the two wells are pulling ethylene dibromide, or EDB, a highly toxic aviation fuel additive, toward the wells as intended, she said.
“That’s exactly what you want to see,” Agnew said. “We should see EDB mass increasing at the extraction wells and decreasing elsewhere in the plume.”
The Air Force is rehabilitating a third extraction well, and a fourth was completed last month. All four wells should be in use by the end of the year, Agnew said.
The fuel leak originated at a jet fuel facility at Kirtland that was used for decades before the leak was first detected in 1999. The key concern has been that the leak will pollute drinking water wells in the Southeast Heights.
Since June 2015, 152 million gallons of groundwater have been extracted, piped to a facility on the base, and filtered through granular activated carbon tanks, Agnew said.
The number of 20,000-pound tanks was recently increased from two to four, she said.
The treated water is used to irrigate a golf course at Kirtland, or discharged into the aquifer at a new test well on the base.
The fuel leaked from four dime-sized holes in a pipe, Adria Bodour, a U.S. Air Force civil engineer leading the remediation, said at the meeting.
No one is certain when the leak began, but the use of EDB as a jet fuel additive ceased in 1975, Bodour said. The fuel saturated soil to a depth of about 480 feet, where it contaminated groundwater, forming a contamination plume that extends north beyond Gibson SE.