Tucson International Airport Area

Tucson International Airport

Superfund Site | Airport Property

EPA #: AZD980737530

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

Location

The Airport Property Project Area is located in the central portion of the Tucson International Airport Area (TIAA) Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) site. It is bounded approximately by Los Reales Road to the south and Elvira Road to the north. The Tucson International Airport lies just east of the project area.

Contaminants of Concern

The current contaminants of concern in groundwater include volatile organic compounds (VOCs), mainly trichloroethene (TCE).  The concentration of TCE currently ranges from less than 0.5 parts per billion (ppb) to 1,100 ppb.  The federal drinking water standard for TCE is 5.0 ppb. 1,4-Dioxane has also been found in groundwater at the site, but there is no federal or state drinking water standard for this compound. Contaminants of concern in the soils include polychlorinated biphenyls (PCBs), TCE, 1,1-dichloroethene (DCE), and carbon tetrachloride. Contaminants of concern at the site may change as new data become 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 and water is now supplied from outside the site. 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 regional aquifer is composed of two hydrostratigraphic units: the upper zone of the regional aquifer and the lower zone of the regional aquifer. The upper zone of the regional aquifer is composed mainly of gravelly sand with some clayey sand and sandy clay, and it extends to a depth of about 200 feet below ground surface (bgs). The lower zone of the regional aquifer is composed mainly of relatively finer materials including clayey sand with lenses of gravelly sand and sandy clay, and it extends from about 300 feet bgs to an unknown depth. Separating the upper and lower zones of the regional aquifer is a thick clayey sequence termed the middle aquitard. This unit generally prevents contamination in the upper zone from reaching the lower zone.

At the Airport Property project area there is also a shallow groundwater zone (SGZ) that overlies the upper zone of the regional aquifer. The SGZ is composed mainly of fine grained silts and clays. Within the SGZ there are gravel subunits that channel groundwater flow westward and downward into the upper zone of the regional aquifer. The gravel subunits are coarser sediments including fine to coarse-grained sands and gravels.

Depth to groundwater varies from 80 to 240 feet bgs and generally gets deeper in a northward or westward direction. The general groundwater flow direction is toward the north-northwest; however, the gravel subunits within the SGZ channel flow more westward. More detailed descriptions of the hydrogeology of the Airport Property Project Area can be found in reports and studies available at the TIAA Information Repository.