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WQARF | 7th St & Missouri Ave - Overview


7th Street and Missouri Avenue | Overview

Revised On: Jan. 2, 2024 - 4:00 p.m.

Registry placement date:  June 24, 2016

Score: 42

County: Maricopa


Phoenix, approximately bounded to the north by East Montebello Avenue, to the south by East Georgia Avenue, to the west by North 6th Street, and to the east by North 10th Street.

If you own a private well, live in or near the site boundaries, and have not had your well tested, please contact ADEQ.

Contaminants of Concern

Chlorinated solvents tetrachloroethene (PCE) and trichloroethene (TCE) 

Action Taken

PCE and TCE were initially detected in the late 1990s in groundwater samples collected as part of a petroleum underground storage tank assessment. Two areas of elevated PCE concentrations were found during the PI. In 2016, Fashion Cleaners entered into ADEQ’s Voluntary Remediation Program (VRP) to address cleanup of their portion of the contamination. Sample results showed this site as separate from the 7th Street and Missouri Avenue WQARF site.

The remedial investigation (RI) for the 7th Street and Missouri Avenue site occurred from 2016 to 2018. The RI identified the southwest corner of 7th Street and Missouri Avenue as the likely source area. At the southwest corner, sample data indicated that PCE levels in soil exceeded the non-residential Soil Remediation Level (SRL). Groundwater data also confirmed this location had the highest concentrations of PCE in groundwater at the site. The Final RI report was released on Nov. 22, 2018.

Research into the history of the area found that a former dry cleaner operated in this location prior to the current building, which was constructed in 1986. Data also confirmed that the nearby Fashion Cleaners and its ongoing remedial activities through the VRP is a separate release, unrelated to the 7th Street and Missouri Avenue Site | View Fashion Cleaners VRP Site Information >

In October 2018 ADEQ installed a Soil Vapor Extraction System (SVE) as an Early Response Action (ERA) for source control. In November 2018, ADEQ installed an Ozone Sparge Injection pilot test system to evaluate the technology as a possible remedy for groundwater at the site.

ADEQ issued the Feasibility Study (FS) in November 2019. The FS report evaluated three different approaches to address the soil and groundwater contamination at the site. Within the FS, ADEQ selected a soil remedy which included expanding the blower and efficiency of the current SVE system. As a groundwater remedy, ADEQ selected expanding the current Ozone Sparge Injection pilot test system at and near the source area and monitored natural attenuation (MNA) for the diffuse plume. The FS also described contingencies, including additional ozone sparge areas and wellhead treatment for nearby groundwater extraction wells.

ADEQ further detailed the proposed remedy in the Proposed Remedial Action Plan, which was released for public comment on March 26 through June 23, 2020 | View Public Notice/Related Documents > 

An expansion to the Ozone Sparge system was installed as an ERA in July, 2020. The Record of Decision (ROD) was issued November 2, 2021. The selected remedy is SVE for soils, and ozone sparge with monitored natural attenuation (MNA) for groundwater | View Public Notice/Related Documents >


The ROD and implementation of the final remedy are on hold as ADEQ and SRP work together to determine a path forward at this and other Phoenix sites. ADEQ is currently awaiting approval from SRP to sample the SRP well at this site to help with this determination.

Community Advisory Board (CAB)

Established and merged with the Central Phoenix Community Advisory Board (CAB). For more information on joining the CAB, or to be included on the site mailing list, please contact the community involvement coordinator. A list of CAB members and their contact information is available in the Community Involvement Plan (CIP) | View/Download CIP >