Phoenix-Goodyear Airport North
The Phoenix-Goodyear Airport (PGA) Superfund site is located approximately 17 miles west of Phoenix in Goodyear, Ariz. The PGA Superfund site is divided into a northern portion called PGA North (PGAN) and a southern portion called PGA South (PGAS) and the contamination from these two areas is not contiguous. PGAN consists of the former Unidynamics Phoenix Incorporated property, consisting of the main dry well source area (MDWSA) and groundwater contamination originating from the property. The PGAN site lies almost entirely within the City of Goodyear. The plume boundary varies and extends beyond the MDWSA but remains part of the site.
As of November 2014, the PGAN site consists of five groundwater treatment systems, 10 injection wells and a Soil Vapor Extraction (SVE) system. More than 120 wells are part of the groundwater monitoring network to track groundwater flows, contaminant concentrations, and groundwater elevations.
The northern boundaries of the trichloroethene (TCE) plume (north of Interstate 10) are close to being contained. Analyses conducted from 2011 to the present indicate that there is complete capture of the Subunit A (upper portion of aquifer) TCE plume in the east/northeast region of PGAN. These results indicate the extraction and injection systems on the northeast boundary of the plume are performing as designed, which is to stop plume migration to the east towards City of Avondale drinking water wells. The northwest boundary had new Subunit A monitoring wells installed, a new extraction well EA-08 brought online in 2011, and an injection system in the northwest area was installed and became operational in July of 2014. Initial analysis of capture to the northwest in 2014, indicates capture is complete in the Subunit A TCE plume in the northwest region of PGAN.
In 2011, the Source Area Remedial Focus Feasibility Study (SARFFS) was initiated. The goal was to evaluate remedial technologies that may assist in expediting the clean up of PGAN. The SARFFS was completed in October 2013. After reviewing the technologies evaluated in the SARFFS and weighing the advantages and disadvantages of each against the remedial action goals set for the project, EPA wrote the proposed plan for the MDWSA Area. EPA released the proposed plan for public comment in 2014 and selected the remedial alternative and documented this decision in an amendment to the record of decision (ROD Amendment) on September 30, 2014. In 2015, an additional extraction well and an additional injection well are planned to complete containment in the area south of I-10.
A community advisory group (CAG) was formed in January 2001 in conjunction with PGAS and Western Avenue WQARF sites and met on a regular basis. In Fall of 2014 the CAG was disbanded with the movement of the Western Ave WQARF site to the Record of Decision phase. Historical meeting agendas and minutes can be viewed on the ADEQ web site.
EPA will be forming a new CAG to serve the affected community in Spring 2015. EPA publishes fact sheets that are sent to the community involvement area regarding PGAN progress, and the latest fact sheet can be viewed on the ADEQ website. An updated Community Involvement Plan was completed in July 2013. An updated Community Involvement Plan was completed in July 2013 and will be updated in conjunction with the formation of the new CAG.
1963 - 1981: Unidynamics operated a research, design and manufacturing facility for ordnance and related equipment from 1963 to 1993. Several different chemicals, including solvents such as TCE, acetone and methyl-ethyl-ketone, were used in manufacturing devices and were reportedly disposed of in drywells at PGAN. The Arizona Department of Health Services discovered the groundwater contamination in 1981.
1983: EPA added PGAN to the NPL in September.
1984: EPA began an Remedial Investigation (RI) of the area now known as the PGA to characterize the site, discover the extent of the contamination, and identify possible sources. From this study, the entire site was divided at Yuma Road into a north and a south portion.
1990: In September, EPA issued an Administrative Order directing Unidynamics to proceed with soil and groundwater remediation as described in EPA's 1989 Record of Decision. The groundwater portion of the remediation program involves extracting the groundwater, removing the contaminants by air stripping with emissions control, and reinjecting the treated water into the same aquifer upgradient of the plume or discharging the treated water to the Roosevelt Irrigation Canal.
1994: For treatment of soil contamination, an SVE system began operation and included a thermal oxidation unit equipped with an exhaust scrubber to reduce emissions.
1998: Perchlorate contamination was discovered and began to be included in the current groundwater monitoring regime.
2002 - 2003: The Phase II groundwater investigation conducted by EPA, yielded valuable data; however, additional investigation was needed to further characterize the nature and extent of the groundwater contamination and the soils at the Unidynamics facility.
2004 - 2006: EPA and ADEQ worked with Crane Co. to finalize a subsurface soil gas investigation to better understand the facility; re-started the SVE system with carbon treatment to address soil gas contamination; continued to investigate the nature and extent of TCE and perchlorate contamination; and continued to study the effectiveness of treating perchlorate-contaminated groundwater at the City of Goodyear's wastewater treatment plant, Crane Co. ultimately decided to install an ion-exchange system to treat perchlorate rather than treating perchlorate- contaminated groundwater at the City's wastewater treatment plant. EPA and Crane Co. concluded negotiations and entered into a CD that commits Crane Co. to repay EPA for past expenses and directs Crane Co. to continue investigation and clean up of the site.
2006: Crane Co. installed nine monitor wells, one groundwater extraction well and one groundwater re-injection well.
2008: An extraction well (EA-05) and treatment system located on Maricopa Flood Control District lands north of I-10 near Litchfield Road was operational at the end of March. This extraction and treatment system was designed to further address the eastern migration of the contaminant plume. EPA issued an Action Memorandum addressing perchlorate clean up levels for PGAN to be 14 micrograms per liter (µg/l).
2009: Demolition of the buildings at the Unidynamics facility began in March and was completed in July. All wells were installed per the approved work plan and installation of the next phase of wells began in summer 2009. Crane Co. also focused on an expansion of the MTS located on the Unidynamics site.
2010: The northeast treatment system expansion project was completed and brought on line in September. The MTS was expanded to include an additional air stripper and converted well MW-29 into an extraction well. The 2010 Five Year Review (FYR) was completed and signed by ADEQ and EPA in September. Two piezometers, seventeen monitoring wells, one extraction well and three injection wells were installed during the year.
2012: Beneficial reuse of treated water at the St. Thomas Aquinas Church for the HVAC system was completed. New Subunit A and Subunit C wells (13 total) continue to be installed along with continued groundwater investigations. O & M improvements on extraction and treatment systems continue; including the pipeline separation of extraction wells EA-02 and MW-29 to improve pumping and hydraulic control.
2013: Three Subunit B monitoring wells were installed to achieve a better understanding of vertical migration of the contamination. The final draft of SARFFS was submitted for agency review and finalized. EA-09 extraction well began operating in October. Several O & M improvements were made on the 5 treatment systems. Numerous additional Subunit A and Subunit C groundwater monitor wells installed as part of the ongoing groundwater investigation. Northwest injection system is under construction with a completion date expected in early 2014. SVE Phase I optimization which began in 2012 was completed and a work plan for Phase II optimization was submitted.
2014: EPA wrote the Proposed Plan, detailing an additional remedy for the MDWSA. The Proposed Plan was released by EPA for public comment. The remedy selected in the proposed plan was documented in the ROD amendment signed by EPA on September 30, 2014.
The current contaminants of concern at PGAN include chlorinated solvents, mainly TCE, and perchlorate. TCE is present in the subsurface soils located within the Unidynamics property, as well as in the groundwater. Perchlorate was discovered in the groundwater in August 1998. Contaminants of concern at PGAN may change as new data become available.
Potential health risks may exist for individuals who ingest the contaminated groundwater. The City of Goodyear, City of Avondale, Liberty Utilities (formerly Litchfield Park Service Company and other entities regularly monitor their drinking water supply wells, as required by law. Annual reports regarding the quality of the drinking water supplies can be found at the following web links:
PGAN lies within the basin and range physiographic province, consisting of alluvial basins interspersed by mountain ranges. The alluvial deposits of the western Salt River Valley consist of the Upper Alluvial Unit (UAU), the Middle Fine-grained Unit, or Middle Alluvial Unit (MAU) and the Lower Conglomerate Unit, or Lower Alluvial Unit (LAU). The UAU is approximately is divided into three subunits: Subunit A, Subunit B, and Subunit C. Subunit A contains the bulk of the groundwater contamination beneath this site. Groundwater contained within Subunit C is pumped for use as drinking water and for agricultural purposes.
Groundwater flow direction is largely influenced by pumping as there are multiple domestic, municipal, irrigation, and remediation (extraction and injection) wells in the vicinity of PGAN.
*In Arizona, but outside the Phoenix area, call toll-free at (800) 234-5677.
Interested parties can review select site documents at the City of Goodyear Library, 250 N. Litchfield Road, Suite 185, Goodyear, AZ 85338, (602)-652-3000.
Interested parties can review site information here on this page and at the ADEQ Record Center located at 1110 W. Washington Street, Phoenix, Arizona. Please contact (602) 771-4380 or (800) 234-5677 ext. 6027714380 for hours of operation and to schedule an appointment.
The complete official site file can be reviewed at the EPA Region IX, Records Center, Mail Stop SFD-7C, 95 Hawthorne Street, Room 403, San Francisco, CA 94105, (415) 536-2000.