162nd Fighter Wing Arizona Air National Guard

Fighter jet taking off at AANG

Superfund Site | 162nd Fighter Wing Arizona Air National Guard: Page 2 of 2

Action Taken

A pump and treat remediation system was installed at the AANG project area in May 1997 to capture and treat groundwater contaminated with VOCs and to prevent offsite migration by maintaining hydraulic control of the TCE groundwater plume. Between May 1997 and May 2012, a total of approximately 820 million gallons of groundwater were treated, and approximately 39 pounds of TCE were removed from the upper regional aquifer. The system was shut down in May 2012 and a quarterly groundwater monitoring rebound program began.  An SVE system operated at Site 5 from April 1996 to November 1997, and an In-Situ Chemical Oxidation (ISCO) pilot test was conducted in 2008.

Status

The pump and treat remediation system is still shut down because TCE concentration levels in groundwater are now below federal maximum contaminant levels (MCLs) in most AANG wells. 

Following issuance of a Record of Decision (ROD) Amendment in April 2012, EPA and ADEQ entered into discussions with the National Guard Bureau (NGB) and the AANG to implement the ISCO remedy for the AANG site.  In late 2014, the NGB/AANG began Remedial Design activities, and in the spring of 2015 the AANG conducted baseline groundwater sampling of approximately 100 monitoring wells within the AANG and West Plume B project areas. EPA and ADEQ are still negotiating with the NGB and AANG to develop a final design and implement the ISCO remedy.

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