East Central Phoenix (ECP) 24th Street and Grand Canal
The ECP 24th Street and Grand Canal WQARF (site) plume, in Phoenix, Arizona, is approximately bounded by East Pinchot Avenue to the north, East Winsor Avenue to the south, North 25th Street to the east and North 22nd Street 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.
As part of Prospective Purchaser Agreements (PPA), CVS Pharmacy conducted a limited site assessment at the former location of a dry cleaner at the northeast corner of 24th Street and Thomas Road. A groundwater sample collected from a newly installed monitor well in July 2008 indicated a tetrachloroethene (PCE) concentration of 200 micrograms per liter (µg/L). Sampling of the SRP well in October 2008 yielded a PCE concentration of 12 µg/L which is over the Aquifer Water Quality Standard (AWQS) of 5 µg/L.
In fiscal year 2015, groundwater and soil vapor monitor wells were installed throughout the site. A draft Remedial Investigation(RI) report was not completed due to the need for additional groundwater monitoring. Design and implementation of a soil vapor extraction (SVE) remediation system has been initiated as part of an early response action (ERA) near the CVS Pharmacy at the corner of 24th St and Thomas Rd. Site investigation will continue throughout fiscal year 2016.
A community advisory board (CAB) was formed in November 2007. The CAB meets on a regular basis. Details of CAB meeting agendas and minutes can be viewed at the ADEQ website. These meetings are open to the public.
1985 - 1988: Groundwater samples were generally collected by SRP from their well, 16.0E-6.8N, which is located east of the intersection of 24th Street and the Grand Canal. A sampling event conducted in January 1995 yielded the highest detection of PCE yet observed in the SRP well, a concentration of 8.8 µg/L.
2000: In May, the site was placed on the WQARF Registry with a score of 29 out of a possible 120. Groundwater sample collection from the SRP well has generally been conducted by ADEQ on a yearly basis with levels of PCE above the AWQS of 5.0 µg/L.
2002 - 2006: Routine groundwater monitoring activities were conducted at the site by ADEQ. The PCE concentration in the SRP well ranged from 7.9 µg/L to 11 µg/L.
2007: In June, ADEQ sent out notices per A.R.S. §49-287.03 initiating the remedial investigation (RI) for the site. During a routine groundwater monitoring event, PCE was detected in the SRP well at a concentration of 12 µg/L.
2008: As part of a PPA, CVS Pharmacy conducted a limited site assessment at the former location of a dry cleaner on the northeast corner of 24th Street and Thomas Road. As a condition of the PPA, CVS Pharmacy installed an onsite groundwater monitor well located northeast of the intersection of North 24th Street and East Thomas Road. The initial groundwater sample collected from the well had a PCE concentration of 170 µg/L. CVS Pharmacy also conducted a soil and soil vapor survey to 85 feet below ground surface (bgs). PCE concentrations in soil ranged from less than the laboratory reporting limit to 0.20 milligrams per kilogram (mg/kg). The highest concentration of PCE detected in soil vapor was 2,000 parts per billion by volume (ppbV) from a sample collected at 50 feet bgs.
During a routine groundwater monitoring event, PCE was detected in the SRP well at a concentration of 12 µg/L. The groundwater monitor well located on the CVS Pharmacy property was sampled at multiple depths. The PCE concentrations ranged from 230 to 260 µg/L.
2014: In FY 2014, a total of 5 groundwater monitor wells were installed throughout the site and a total of 68 groundwater samples were retrieved. A draft RI report was not written due to insufficient data and the need for more groundwater monitoring wells. Site investigation and groundwater well installation will continue throughout FY15 and a draft RI report will be submitted by June 30, 2015.
2015: In fiscal year 2015, a total of 5 groundwater and 4 soil vapor monitor wells were installed throughout the site. A total of 124 groundwater samples and 32 soil vapor samples were collected. A draft Remedial Investigation(RI) report was not completed due to the need for additional groundwater monitoring. Design and implementation of a SVE remediation system has been initiated as part of an ERA near the CVS Pharmacy at the corner of 24th St and Thomas Rd. Site investigation will continue.
The current contaminant of concern in groundwater is PCE. Contaminants of concern at the site may change as new data become available.
SRP occasionally pumps Well 16.0E-6.8N for irrigation use. However, SRP monitors the well for contamination and will cease using the well, if contamination is detected above allowable standards.
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.
Based on the boring log for SRP Well 16.0E-6.8N, the site is underlain by clayey and silty sands with minor sand lenses from ground surface to approximately 70 feet bgs. From approximately 70 to approximately 396 feet bgs, a gravelly clay unit exists. Decomposed granite is encountered at approximately 396 feet bgs, and competent granite is encountered at approximately 580 feet bgs. Previous sampling events indicate that groundwater flows to the southwest.
*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.