West Central Phoenix (WCP) North Plume
The WCP North Plume WQARF site is located in Phoenix, Arizona. The contaminated groundwater plume is bounded approximately by West Highland Avenue to the north, Indian School Road to the south, 37th Avenue to the east, and 43rd Avenue 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 continues to operate the soil vapor extraction (SVE) system at the F & B Manufacturing (F&B) facility. To date, the system has removed more than 46,000 pounds of volatile organic compounds (VOCs). During the first half of 2015 the system removed, on average, 211 pounds of tetrachloroethene (PCE) from the soil each month.
A community advisory board (CAB) has been formed for the sites. These meetings are open to the public. Details of meeting agendas and minutes can be viewed at the ADEQ website.
1967 - 1991: The F&B facility is located near 39th Avenue and Montecito Avenue. Since 1967, F&B has been manufacturing metal aircraft and spacecraft parts and performing sheet metal forming, and assembly. Solvents are used as degreasing agents to clean the surface of the metals. PCE was used as the degreasing solvent until approximately October 1987, when it switched to 1,1,1-trichloroethane (TCA). In April 1991, ADEQ discovered information that PCE had leaked from F&B's degreaser into the soil under the building.
1969: The Hill Brothers Chemical Company (HBCC), a facility in the North Plume project area facility is located near 42nd Avenue and Turney Avenue. The Hill Brothers facility has operated as a chemical distribution facility at this location since 1969. Chemicals that include acids, bases, solvents, chlorine, and concrete additives were stored in above ground storage tanks on-site prior to transfer into containers for distribution.
1977: The former Pyramid Industries, Inc. (Pyramid) facility is also located near 39th Avenue and Montecito Avenue, across from the F&B facility. Pyramid operated a telephone and television cable riser box manufacturing facility from 1977 to 1994. Operations at the facility required the use of acids, caustics, heavy metals, paints, and methylene chloride. Several suspected sources of contamination have been identified on the Pyramid facility, including the loading dock/drywell, paint room, and historic hook cleaner area.
1982 - 1989: VOCs were first detected in groundwater in the WCP area in July 1982. The City of Phoenix (COP) detected trichloroethene (TCE) in four municipal public supply wells, COP Wells #70, #71, #151, and #152. The Arizona Department of Health Services , Salt River Project and the 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. Wells #151 and #152 were monitored for VOC concentrations from 1982 until 1989. As a result of sampling conducted during February of 1989, COP elected to take both wells #151 and #152 off-line on March 7, 1989.
The former Rinchem Company, Inc. facility is located near 41st Avenue and Turney Avenue. Rinchem operated a chemical warehouse and distribution facility from 1982 through June 1993 that handled solvents, oils, and fuels. Several suspected sources were identified on the Rinchem facility, including the former repackaging area and former tank farm.
Field investigation activities for the site have been conducted between 1984 and the present time. Several contaminants have been detected in soil and groundwater samples collected during field investigations at the four facilities. The primary contaminants of concern were TCE, PCE, and 1,1-dichloroethene (1,1-DCE).
Four facilities were identified as likely sources of the groundwater contamination in the site. The four facilities were as follows: the F&B facility, Pyramid facility, former Rinchem facility, and Hill Brothers facility. Field investigation activities at the four facilities in the site have been conducted since 1984.
In 1987, the WCP area was designated a WQARF priority list site.
1992: ADEQ entered into a consent decree (CD) with F&B to conduct a remedial investigation (RI)/feasibility study (FS), remediate PCE-contaminated soil on-site, reimburse past costs and pay oversight costs.
1995 - 1999: From 1995 until 1998, F&B was financially unable to fulfill the requirement under the CD. Between 1998 and 1999, ADEQ and F&B negotiated a new CD, which was approved by the Court in August 1999. As stated under the new CD, ADEQ would complete the RI/FS and conduct the remediation of the facility. In 1999 ADEQ and F&B entered into a financial hardship CD in Federal Court. Under the CD, ADEQ conducts the RI/FS and remediation. F&B was required to make annual payments for a period of time in amounts calculated as a percentage of net sales.
In ADEQ established a registry for WQARF sites which replaced the priority list. The site was placed on the WQARF Registry in April 1998 with a score of 50 out of a possible 120. The site score was re-evaluated in 2000 with a revised score of 55.
2000 - 2006: ADEQ operated an SVE system at the F&B facility since August 2001 to remediate the PCE contamination beneath the vapor degreaser. In addition, ADEQ removed approximately 210 cubic yards of soil beneath the vapor degreaser during two excavations in July 2000 and September 2001. As of December 2006, over 41,000 pounds of PCE were removed from the source area by the SVE system.
2006: In August, ADEQ issued the draft RI report. Groundwater samples and water level measurements were collected in September.
2007: As of December, over 41,400 pounds of VOCs were captured by the SVE system at the F&B manufacturing facility. ADEQ had a Groundwater Risk Model performed with information available from the former Rinchem facility. Based upon the results of the model, it was determined that the concentration of VOCs in the soil did not merit the placement of a remedial system.
2008: Three new wells were installed in the project area. One well was the result of a Prospective Purchaser Agreement (PPA) with the state of Arizona. In a public benefit arraignment the new well was installed in the western portion of the project area. Additionally, two wells were installed in an effort to evaluate the potential to capture and treat contaminated groundwater.
Hill Brothers Chemical Company installed an SVE treatment system to be operated to remediate potentially contaminated soils beneath the facility.
2009: The SVE treatment systems continued to operate to further remove VOCs from the soil and eliminate the VOCs from becoming potential contaminants in the groundwater in the WCP area.
2010: The SVE system at F&B was shut down during the first quarter of 2010.. The system was restarted in April. The SVE system at HBCC was shutdown and dismantled. NFA for soils underlying the HBCC facility was issued.
2011 - 2012 The SVE system at F&B was shut down in February because of high moisture content in the air stream. The system was restarted in April.
2013: Three new SVE wells were installed and connected to the existing SVE system at F&B. This SVE system was shut down at the end of January due to high moisture content in the air stream. The system was restarted at the end of April. Groundwater monitoring and sampling was conducted in March and September. Groundwater elevations were measured in June and December.
2014: This SVE system was shut down at the end of December due to high moisture content in the air stream. The system was restarted at the end of March. The SVE system was modified in June to more efficiently remove moisture from the air stream to allow operation of the system year round. Granular activated carbon (GAC) was changed out in the three lead canisters in June. Groundwater monitoring and sampling was conducted in March and groundwater elevations were measured in June.
2015: The Feasibility Study (FS) report was completed. The SVE system was operated continually except for shutdown for minor maintenance activities. Groundwater monitoring and sampling was conducted in February and March.
The current contaminants of concern in groundwater include the chlorinated solvents PCE, TCE, 1,1-dichloroethene (1,1-DCE). Other contaminants at the site include: benzene, toluene, ethylbenzene, total xylenes, methyl tertiary butyl ether (MTBE), and nitrates. 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 are under asphalt parking lots or asphalt-surfaced storage areas, or under the concrete floors of buildings. 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 underlain by the upper alluvial unit (UAU) which consists of silty sands and sandy silts with interbedded clay layers and gravelly sand zones from ground surface to approximately 80 feet below ground surface (bgs). Beneath the UAU, a 35-foot thick fine grained unit consisting of primarily silt, clay with silty sand and gravel interbeds exists, referred to as the middle alluvial unit (MAU). Beneath the MAU, the lower alluvial unit (LAU) is encountered, which overlies bedrock.
Depth to groundwater has declined in the past several years, attributed principally to the ongoing drought. In 1999, the depth to groundwater in the UAU was approximately 122 feet bgs. By 2002, the depth to groundwater was approximately 132 feet bgs. Depth to groundwater as of March 2004 was 120 feet to 145 feet bgs. Currently, depths to groundwater range from approximately 130 feet bgs to 163 feet bgs. The site sits along a groundwater divide in the UAU with groundwater flowing to the northwest across most of the site and to the southwest in the far southern part of the Site. The coarse grained interval in the MAU acts as a groundwater sink, with water level elevations approximately 30 feet lower than the UAU and approximately 15 feet lower than the LAU. Groundwater flow direction in the coarse grained interval in the MAU is to the west.
*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
Final Remedial Investigation Report: