West Central Phoenix (WCP) West Grand Avenue
The WCP West Grand Avenue (WGA) WQARF site is located in Phoenix, Arizona. The contaminated groundwater plume is bounded approximately by Osborn Road to the north, Earll Drive to the south, 33rd Avenue to the east, and 34th Drive 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.
Groundwater sampling was conducted in April 2015. No contaminants were detected at concentrations greater than Aquifer Water Quality Standards (AWQS). A feasibility study (FS) report was completed in June 2013.
1967 - 2002: The Layke facility is located near 33rd Avenue and Osborn Road. Layke began operations at the facility in 1967. Operations included the manufacturing of various metal parts. Trichloroethene (TCE) was the primary solvent used for parts cleaning/degreasing and a vapor degreaser had been used at the facility from 1969 to approximately 1989. Used chemicals were stored in 55-gallon drums in the waste storage area or in an underground storage tank (UST) prior to disposal. At various times, it appears that the UST overflowed, causing the waste inside the tank to leak out. The UST was removed in Oct. 1990.
The Arizona Department of Health Services, Salt River Project, and the City of Phoenix (COP) confirmed the presence of VOCs in the groundwater with sampling in 1983, 1985, and 1986. Groundwater from COP wells #70 and #71 contained the highest concentrations of TCE and, therefore, were immediately shut down. Volatile organic compounds (VOCs) were first detected in groundwater in the WCP area in July 1982. COP detected TCE in four municipal public supply wells, COP wells #70, #71, #151, and #152. Wells #151 and #152 were monitored for VOC concentrations from 1982 until 1989. In 1987 the WCP area was designated a WQARF priority list site. As a result of sampling conducted during Feb. of 1989, COP elected to take both wells #151 and #152 off-line on March 7, 1989. Field investigation activities at the site were conducted between 1989 and 2002. The investigation indicated that the source of soil and groundwater contamination at the site is the Layke Incorporated (Layke) facility.
Between 1990 and 1997, an early response action was conducted by Layke, Inc., the current operator at the Layke Facility. In 1990, Layke excavated a waste oil UST that was contaminated with TCE. Soil samples were collected. After the tank was excavated a soil vapor extraction (SVE) system was installed and operated from 1995 to 1997. In 1997, ADEQ established the WQARF Registry which replaced the priority list. The site was placed on the WQARF Registry in April 1998 with a score of 17 out of a possible 120. The site score was re-evaluated in 2000 with a revised score of 22.
Layke operated a SVE system from March 1995 through June 1998 to remediate the contamination beneath the UST. Between 2001 and 2002, soil samples were collected by ADEQ in the area of the UST to determine the effectiveness of the SVE system in cleaning up the soils. The soil data indicated that the contamination had been effectively remediated by the SVE system. Based on this information, ADEQ granted a No Further Action request in December 2002, pursuant to Arizona Revised Statutes (A.R.S.) §49-287.01
2004: In February, ADEQ issued the draft remedial investigation (RI) report for the site for public comment to meet the requirements established under A.R.S. §49-287.03 and Arizona Administrative Code (A.A.C.) R18-16-406. No comments were received during the 30-day comment period. The report was accepted as the final RI report. ADEQ received a request from Layke in April to permanently shutdown the SVE system. ADEQ granted the request in a letter dated April 21st.
2005: In October, ADEQ issued the proposed remedial objectives (RO) report for public comment.
2008: Because of a decline in groundwater levels, the WGA wells went dry so a new groundwater monitor well, WCP-235, was installed at the site. To date, testing in the WGA area indicates no exposure to the contamination. Sampling shows that the contaminated soils are remediated. Notices have been sent out to all known residences within the WGA area for the testing of possible domestic wells for contamination. The area is served by the City of Phoenix municipal water system or other regulated systems.
2012 - 2013: The FS report was completed in June 2013. Groundwater sampling was conducted in Oct. 2012 and Jan. 2013. No contaminants were detected at concentrations greater than the Arizona Aquifer Water Quality Standards (AWQS).
2014: Groundwater sampling was conducted in December. No contaminants were detected in the groundwater sample.
2015: Groundwater sampling was conducted in April. No contaminants were detected at concentrations greater than the AWQS.
The current contaminant of concern in groundwater includes the chlorinated solvent TCE. Contaminants of concern at the site may change as new data become available.
To date, testing in the WCP area indicates no exposure to the contamination. Sampling shows that the contaminated soils were remediated and ADEQ granted the site no further action in December 2002. Contaminated drinking water wells in the area have been shut down. In addition, notices have been sent out to all known residences within the WCP area for the testing of domestic wells for contamination.
The site is located within the West Salt River Valley sub-basin of the Phoenix Active Management Area. The Salt River Valley is an alluvial filled basin located in the basin and range physiographic province. The site is underlain by primarily sandy silts and silty sands with interbedded clay layers and gravelly sand zones.
Due principally to the ongoing drought, depth to groundwater has declined considerably in the past several years. In 1992, the depth to groundwater was approximately 98 feet below ground surface (bgs), and by April 2002, it was approximately 124 feet bgs measured in monitor Well WCP-10. The most recent depth to groundwater measured in January 2013 was 138.37 feet bgs. Groundwater flow is to the south-southwest beneath the site.
*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.Site Map