Revised On: Feb. 8, 2023 - 2:59 p.m.

2022: Conducted groundwater sampling in March and October.

2021: Conducted groundwater sampling in March and October.

2020: Conducted groundwater sampling in March and November.

2019: ADEQ completed two additional rounds of enhanced reductive de-chlorination (ERD) injections in January and April and conducted groundwater sampling in April and October.

2018: ADEQ completed two additional rounds of ERD injections to accelerate the Monitored Natural Attenuation (MNA) remedy. Two replacement groundwater monitoring wells were installed to replace wells that have gone dry due to decreases in the groundwater levels.

2017: ADEQ finalized the Record of Decision (ROD) and completed an additional round of ERD injections. ADEQ evaluated the option to increase the frequency of ERD injections to accelerate the MNA remedy.

2016: ADEQ finalized the Proposed Remedial Action Plan (PRAP) for public review and comment. ADEQ initiated an ERD injection to determine if ERD could be cost effectively implemented to expedite the proposed remedial option of MNA. Groundwater sampling results are currently being compared to determine viability of this option.  If effective, this technology may be incorporated into the final MNA remedy for the site to facilitate accelerated site delisting.

2015: ADEQ finalized the Remedial Investigation (RI) report, Feasibility Study (FS) work plan, and the FS report. Groundwater monitoring and sampling was conducted in February and March 2015. The sampling results show that contaminants of concern were continuing to attenuate.

2014: Two groundwater monitoring wells were installed at the site to delineate the down gradient extent of the northern plume. Groundwater samples were collected from all of the site wells that could be accessed in February and April. Based on the April 2014 groundwater sampling event, the current highest concentration of tetrachloroethylene (PCE) and dichloroacetic (DCA) in groundwater is 13.3 micrograms per liter (µg/l) and 0.62 µg/l, respectively. The sampling results for dichlorophenol (DCP) continue to show no concentrations above laboratory reporting limits.

2013: Based on the May groundwater sampling event, the highest concentration of PCE in groundwater was 31.9 µg/l. Groundwater samples for 1,2-DCA concentrations remain below the laboratory detection limit. ADEQ is in the process of installing two groundwater monitoring wells to further define the down gradient extent of PCE contamination of the North Plume.

2008: ADEQ continued to sample the northern and southern groundwater plumes.

2007: Based on the October groundwater sampling event, the highest concentration of PCE and 1,2-DCA in groundwater was 24 µg/l and 3.4 µg/l, respectively.

2004 – 2006: An Early Response Action (ERA) completion report was completed.  Groundwater monitoring of the well network continued at the site. There were 13 wells monitored and sampled on the site as part of the monitoring well network.  Passive diffusion bags are used at the site, due to a drop in the depth of groundwater. Passive diffusion bags were first used during the 1st quarter 2004 sampling event.

ADEQ installed an additional well, MW-12, in January 2004, on the property located on the southwest corner of 16th Street and Camelback. The purpose of the well was to aid in defining the down gradient extent of PCE contamination.  Due to declining water levels, in April 2006, ADEQ installed well MW-3A to replace well MW-3. The purpose of well MW-3A is to collect contamination data from the source area of the southern plume.

The highest concentration of PCE in groundwater at the site was 89 µg/l based on the August 2006 sampling event. The highest concentration of 1,2-DCA in groundwater was detected at 7µg/l. No concentrations of 1,2-DCP were detected above laboratory reporting limits. 

2003: In January, ADEQ installed two vapor extraction wells, one sparge point and two observation wells. A pilot study was conducted to determine the feasibility of installing a vapor extraction/air sparge remediation system. In April, ADEQ received the results from the pilot study and requested that an ERA completion report be prepared. The results of the pilot study indicated that installation of a remediation system at the site is not feasible or cost effective.

2002: In May, ADEQ began an ERA evaluation at the site. The ERA evaluation was designed to determine if soil vapor extraction (SVE) and air sparge remediation was feasible to provide source control and remediate the PCE groundwater contamination.

1999: The site was added to the WQARF Registry on April 21st with an eligibility and evaluation score of 23 out of a possible 120.

1996: ADEQ installed four additional permanent groundwater monitor wells and four temporary groundwater well points.

1995: ADEQ conducted a soil vapor survey.  PCE concentrations were detected in soil from 1.3 to 2.3 µg/l.

1994: A Consent Decree was signed in January, between Bank One and ADEQ.  Bank One paid a settlement to ADEQ to be used for the investigation and clean up of the property. Six monitor wells were installed.