Western Avenue PCE
The Western Avenue Plume WQARF site is located in Goodyear/Avondale, Arizona. The groundwater contamination plume is bounded approximately by San Xavier Boulevard (north of Western Avenue) to the north, 3rd Street to the east, State Route 85 to the south and the Phoenix-Goodyear Airport to the west.
The plume boundaries depicted on the site map represent the Arizona Department of Environmental Quality’s (ADEQ) interpretation of the data available at the time the map was constructed. The map is intended to provide the public with basic information as to the estimated extent of known contamination as of the date of map production. The actual extent of contamination may be different. Therefore, the plume boundaries may change in the future as new information becomes available. ADEQ is currently preparing the PRAP for the site with a target completion date of December 2014.
Groundwater elevations and contamination concentrations at the site have been decreasing the last eighteen years and are significantly lower than first discovered. ADEQ continues to monitor a network of wells, including City of Goodyear municipal well, COG-01 tracking contamination at the site and possible threats to drinking water.
A community advisory group (CAG) was formed in January 2001, in conjunction with the Phoenix Goodyear Airport North (PGAN) and Phoenix Goodyear Airport South (PGAS) and meets on a regular basis.. These meetings are open to the public. Details of meeting agendas and minutes can be viewed at the ADEQ website.
1994: ADEQ conducted Preliminary Investigations in 1994 and 1995. Soil vapor sampling at the City of Goodyear Public Works facility and also at Western Dry Cleaners. The soil vapor sampling did not detect any significant concentrations of PCE.
1995: Two monitor wells were installed to characterize the groundwater quality east and north of the PGAS
1998: The site was placed on the WQARF Registry in December with a score of 51 out of a possible 120.
2000: In October, ADEQ installed five monitor wells as part of an early response action (ERA). The purpose of the ERA evaluation was to (1) better define the lateral and vertical extent of contamination, (2) gain a better understanding of where the source area may be located, and (3) to determine the approximate mass of PCE within the plume.
2001: In March, ADEQ conducted a soil gas survey at the former Aladdin Dry Cleaners property. Results of the soil gas survey indicated minor concentrations of PCE. In July, ADEQ began a remedial investigation (RI) at the site.
2002: In October, a draft Industrial Survey was completed as part of the draft RI report which focused on potential source areas. The data obtained from the Industrial Survey indicated that additional source investigations would not be required as part of the RI.
2003: In March, the Industrial Survey report was finalized as part of the draft RI report.
2005: Current and Future Beneficial Land and Water Use report was conducted as part of the draft RI report.
2006: The highest concentration of PCE detected in groundwater was 3.2 micrograms per liter (µg/l) in the March sampling. The draft RI report including the Land and Water Use report, was submitted for public comment in August.
2007: The highest concentration of PCE detected in groundwater during the August monitoring event was 12 µg/l at monitor well MW-2.
2008: Monitor well MW-8 was installed by ADEQ north of the City of Goodyear municipal well, COG-01 before the end of the year. Monitor well MW-8 was installed to provide data to define the northern boundary of the PCE impacted groundwater.
2009: Groundwater samples were collected from site monitor wells in January. The highest concentration of PCE in groundwater was 4.5 ug/l at monitor well MW-2, less that the Aquifer Water Quality Standard (AWQS) of 5.0 ug/l. ADEQ finalized the RI report. The RI incorporated the remedial objectives report that was completed in January. The Feasibility Study (FS) phase began, and groundwater monitoring continues at the site.
2010: Groundwater samples were collected from site monitor wells in May and November. The highest concentration of PCE in groundwater in these two events was 6.8 µg/l at monitor well MW-1.
2011: Groundwater samples were collected quarterly from site monitor wells and groundwater elevations were captured monthly. In May, ADEQ installed passive diffusion bag (PDB) samplers in monitoring wells. In Aug.t and Nov., PDBs were placed at the depth in each monitor well where the PCE concentration was the highest, based on May vertical profiling. The highest concentration of PCE in groundwater during the four events was 12.0 µg/l at monitor well MW-1 in Nov. The AWQS is 5.0 ug/l.
2012: Groundwater samples were collected quarterly The highest concentration of PCE in groundwater during the events was 6.59 µg/l at monitor well MW-1 in May. Verification sampling was conducted in June to verify suspect VOC concentrations at selected wells during the May event. The results of the verification sampling and Aug. sampling indicated that PCE concentrations were within normal ranges (5.3 ug/l). A concentration of 6.2 ug/l was reported in Nov. at MW-1. The draft FS Work Plan was completed April 4th.
2013: Groundwater samples were collected quarterly. The highest concentration of PCE in groundwater during the events was 7.8 ug/l at monitor well MW-1 in May. PCE was not detected at concentrations greater than the AWQS at any of the other monitor wells, including COG-01. To further develop the conceptual understanding of PCE at well COG-01, a time-series groundwater sampling was conducted from March 25 through April 16. The draft summary report was completed May 15 and should be final by the end of 2013. The draft FS report was completed April 4 should be final by the end of 2013.
EPA conducted an “Area Between the Sites” study to collect data to further define water level and water quality conditions in the area where the PGAN, PGAS and Western Avenue sites meet. The scope of the study included the surveying of selected wells in the area to a common region measuring water level elevations and collecting groundwater samples. The final results of the study were finalized in March.
The current contaminant of concern in groundwater is tetrachloroethene (PCE), a solvent commonly used in dry cleaning. Contaminants of concern at the site may change as new data become available.
Due to high nitrate concentrations from historical agricultural land practices, the upper groundwater aquifer is used mainly as an irrigation source. Public drinking water supplied to the area is regularly tested to ensure compliance with regulatory standards.
Groundwater beneath the site exists in three units termed Subunit A, Subunit B, and Subunit C. The site is concerned with the PCE contaminated groundwater that exists in Subunit A. Subunit A consists of alluvial sediments located between the ground surface and approximately 130 feet below ground surface (bgs). Subunit B consists of a thick clay layer and underlays Subunit A. Subunit C consists of alluvial sediments and is believed to exist between approximately 240 and 360 feet bgs.
Groundwater flow is generally to the west. The depth to water in August 2007 ranged from approximately 61 to 72 feet bgs. Water levels are currently nine to 16 feet lower than the highest levels in early 2001. A groundwater divide appears to be present at the site with groundwater flowing to the northwest, north of Well MW-7 and southwest, south of Well MW-7.
*In Arizona, but outside the Phoenix area, call toll-free at (800) 234-5677.
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. To review site information at a location near you, please contact the designated Community Involvement Coordinator.