Tucson International Airport Area

Tucson International Airport

Superfund Site | 162nd Fighter Wing Arizona Air National Guard

EPA #: AZD980737530

Superfund National Priority List (NPL) Status: The EPA listed this site on Sept. 9, 1983

Location

The Arizona Air National Guard (AANG) site is located on the north-central side of the Tucson International Airport and is bounded on the north by Valencia Road, and on the west, south, and east by the Tucson International Airport.

Contaminants of Concern

The current contaminants of concern in groundwater include volatile organic compounds (VOCs); mainly trichloroethene (TCE). Currently, the concentration of TCE in groundwater ranges from less than 0.5 parts per billion (ppb) to 9.3 ppb. The federal drinking water standard for TCE is 5.0 ppb. The Contaminants of concern at the site may change as new data becomes available.

Public Health Impact

The City of Tucson is the main municipal water provider at this site. All municipal wells in the area that were contaminated with TCE have been shut down. Most of the domestic wells have either been shut down or converted to irrigation wells. If you are drinking water from a private well within the boundaries of the TIAA site, please contact the ADEQ Project Manager.

Site Hydrogeology

The vadose zone at the AANG project area extends from the surface to a depth of approximately 88 feet below ground surface (bgs) and is composed of silty sands, caliche deposits, and gravelly sands. The upper zone of the regional aquifer consists of two subunits and a middle aquitard. All of the known groundwater contamination at the AANG project area is found in these three hydrostratigraphic units. The upper subunit consists of well-graded, gravelly, course sand and is found at a depth of approximately 88 to 103 feet bgs. The middle aquitard separates the upper and lower subunits and is composed of tight sandy silt with scattered pebbles. The middle aquitard lies at a depth of about 103 to 128 feet bgs. The lower subunit is found at a depth of approximately 128 to 138 feet bgs and is composed primarily of course-grained sand. There is also a northwest-southeast trending sand channel in the lower subunit along the south-central portion of the AANG base.

The groundwater flow direction in the upper and lower subunits is toward the northwest, and the depth to groundwater is approximately 90 feet bgs. More detailed descriptions of the hydrogeology of the AANG project area can be found in reports and studies available at the TIAA Information Repository.