PUBLIC NOTICE | Proposed Leaking UST Case Closure for Case File 2314.01

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

LUST Case File No.: 2314.01     

Facility ID No.: 0-002921
Maricopa County

Facility address: 
We Buy Scrap
1229 E. Curry Road
Tempe, AZ 85281

Information

The Site is located at 1229 E. Curry Road just east of Miller Road in Tempe and is currently occupied by a scrap metal recycler. The area is a mixture of light industrial and residential development. A release was reported to ADEQ during removal of an 8,000 gallon gasoline underground storage tank (UST) in 1992. The UST owner/operator was Landscape and Maintenance of Arizona Inc. between 1968 and 1998. The contamination eventually reached groundwater. Initial site investigation included soil borings and the installation of several monitoring wells (MWs). MW-1, MW-3, MW-4, MW-5 and MW-6 still remain. The soil was characterized in 1997. Contamination in soil and groundwater was primarily limited to the nearby source area. The UST owner/operator conducted corrective actions until 2000 under the State Assurance Fund.

The current property owner requested the State Lead Unit’s assistance in 2011 to perform corrective actions. The State Lead Unit’s contractor, Hydro Geo Chem, Inc. (HGC) conducted groundwater sampling to evaluate groundwater conditions in 2012. MW-7 was installed down gradient of MW-1 in September 2012 along with soil boring HGC-B1 which was installed near the center of the former tank pit. Based on the drillers logs, soil in the former tank pit was clayey sand and silty sand to a depth of 20 feet, well-graded sand to a depth of 30 feet. Well–graded gravel with sand was observed between 30 and 50 feet, clayey gravel to 60 feet and well-graded gravel with clay and sand to 65 feet. Soil sample analytical data collected at 50 feet had benzene, 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene (TMBs) and total xylenes with concentrations that exceeded the applicable regulatory standards. MW-7 had no volatile organic compounds (VOCs) present in the September 2012 sampling results. A second soil boring (HGC-2) was installed in May 2014. No VOCs were detected over applicable regulatory standards between 10 and 50 feet below ground surface (bgs).

The historic groundwater flow direction has fluctuated. The groundwater flow direction is currently northwesterly. Between 1999 and 2012, the groundwater level increased from 53 to 35 feet bgs. As of March 2017 the depth to groundwater is approximately 45 feet bgs.

Groundwater data has been collected since 1997. Several VOCs historically have been present at concentrations that exceed the applicable regulatory standards. The remedial technology used for the VOC contamination was in-situ chemical oxidation (ISCO) using PersulfOx™. Three nested injection wells were installed in May 2014. ISCO was done between 2014 and 2016. Post injection groundwater sampling indicated VOC concentrations were reduced to below applicable regulatory standards (in most cases to non-detect) in all wells but MW-3 as of March 2017.

A site specific risk assessment and detailed file/information search were also completed. Benzene analytical groundwater results in MW-3 remain above applicable regulatory standards.

Review Document 

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

Public Comment Period 

Dates: May 16 25, 2017  June 16, 2017

Comments may be submitted as follows:
     By Email | Send Email > 
     By Mail (Must be postmarked or received by June 16, 2017):

       ADEQ
       Debi Goodwin
       Waste Programs Division
       1110 W. Washington Street
       Phoenix, AZ  85007 

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