PUBLIC NOTICE | Proposed Leaking UST Case Closure for Case File 5324.01

ADEQ is considering closure of the following leaking underground storage tank (LUST) case:

LUST Case File No.: 5324.01     

Facility ID No.: 0-006442
Gila County

Facility address: 
Pleasant Valley Auto
47817 N. Highway 288
Young, AZ 85554

Information

This commercial property (the Site) is located at 47817 N. Highway 288 in Young.  Young is a small, unincorporated area in Gila County.  The approximate population in 2010 was 666. The Site was used as a service station prior to 1968, but the Underground Storage Tank (UST) owner/operator was never identified. The two USTs were permanently closed in April 2003. The Site operates as an auto parts retail shop (Pleasant Valley Auto Parts) and a small auto repair shop (Pleasant Valley Auto Center).

The State Lead Unit contracted ATC in 2008 to characterize the contamination by installing soil borings and shallow monitoring wells (MW-1 through MW-6). The boring logs indicate that the subsurface stratigraphy consists of clayey silt to a depth of 10 feet below ground surface (bgs), clay with silt and/or sands to 15 feet, and silty sand to 45-feet, which was the maximum depth drilled. The depth to groundwater was at 15 feet bgs.

In 2010, Brown and Caldwell installed six (6) soil borings (SB) were drilled in July 2012. SB-1 and SB-2 were placed at release areas .01 (UST tank) and .02 (dispenser) respectively.  SB-3 through SB-6 were placed for lateral characterization of the release areas. Groundwater was encountered in every boring at approximately 15 feet bgs. The monitoring wells were completed to a depth of 30 feet bgs.  Six shallow monitoring wells are installed on-site.

A soil vapor extractions (SVE) system ran between July 2012 and July 2014.  An air sparge (AS) system ran between June 2013 and July 2014. Several volatile organic compounds (VOCs) historically have been present at concentrations that exceed the applicable regulatory standards. To complement the ozone sparging and SVE, three rounds of PersulfOx® injections were done to remediate the groundwater between 2014 and the end of 2015. Post injection groundwater sampling indicated VOC concentrations were reduced to below applicable regulatory standards (in most cases to non-detect) in all wells but monitoring well MW-3 as of March 2015.

A site specific risk assessment and detailed file/information search were also completed.  Benzene and methyl tert butyl ether (MTBE) analytical groundwater results in MW-1 and MW-5 remain above applicable regulatory standards.

Review Document 

Review results of remedial activities and entire public notice | View/Print >

Public Comment Period 

Dates: June 6, 2017  July 6, 2017

Comments may be submitted as follows:
     By Email | Send Email > 
     By Mail (Must be postmarked or received by July 6, 2017):

       ADEQ
       Rick Brunton
       Waste Programs Division
       1110 W. Washington Street
       Phoenix, AZ  85007 

Documents may also be reviewed in person at the ADEQ Record Center | Learn More >