Main Street and Kofa Avenue Site
The Main Street and Kofa Avenue (site) is located at 965 W. Main Street in the town of Quartzsite, Arizona. The 15-acre site, once the location of Ted's Truck Stop, had two large refueling areas and a total of eight storage tanks. The truck stop is no longer in operation.
Due to declining concentrations of methyl tert-butyl ether (MTBE) and benzene in the soil vapors, the soil vapor extraction (SVE) system did not run in 2013. Since beginning operations in late 2007, the SVE system removed approximately 95,345 pounds of total petroleum hydrocarbons (TPH), 1,259 pounds of benzene and 3,422 pounds of MTBE.
Annual groundwater monitoring at the site indicates only MTBE is still present above the Health Based Guidance Level (HBGL) of 20 micrograms per liter (μg/l) .
The site was transferred to the Underground Storage Tank (UST) Program Section, State Lead Unit as of July 1, 2013. The UST case manager is Mark Rhoades who can be reached at (602) 771-4295.
A community involvement group (CIG) was formed for this site and has since disbanded. Details of historical meeting agendas and minutes can be viewed at the ADEQ website. A dedication ceremony and tour was conducted of the completed remediation system on March 7, 2008 for the public.
1975 - 1998:Between about 1975 and 1998, the Ted’s Truck Stop facility included two large refueling areas (eastern and western dispenser areas), two tire services areas (tire barn and tire shop), six above ground storage tanks (ASTs), and two underground (USTs). In addition, a restaurant, two mobile homes, and two modular office buildings were located at the site. Intermittently between 1975 and 1998, the ASTs were used to store gasoline, diesel fuel, and used oil. The ASTs ranged in capacity from about 1,000 gallons to 250,000 gallons. The 12,000-gallon USTs were in service between 1978 and 1998 and contained gasoline and diesel fuel. Both USTs have been removed
2000: ADEQ was notified that water from a private well near the site had a gasoline odor, and approximately 20 private wells in the area were sampled. When elevated levels of benzene were found in two of the private wells above the Aquifer Water Quality Standard (AWQS) of 5 μg/l, wells were drilled on the site and groundwater sampling was performed.
2004 - 2006:
ADEQ began a groundwater monitoring preliminary investigation at the site. As part of this ongoing investigation ADEQ installed 17 groundwater wells and collected several soil samples at the site. Results indicated that both soil and groundwater had been impacted from releases of gasoline and diesel fuel.
Those tests discovered widespread petroleum hydrocarbon contamination in the groundwater across the entire site. In addition to elevated levels of benzene and MTBE, free product consisting of diesel and gasoline were detected in four wells. Further groundwater monitoring also showed that benzene and MTBE had migrated off the property, and the groundwater contamination extended about one-fourth mile off the site to the north and northeast.
ADEQ initiated an early response action (ERA) evaluation on the site in October to collect data necessary to characterize the source area of PCE contamination below the site. The ERA evaluation consisted of drilling ten soil borings and installation of five soil vapor extraction (SVE) wells and two groundwater monitor wells at the site.
2007: TADEQ began construction of the soil and groundwater remediation system in September, and it was turned on in December. The remediation system consisted of five Soil Vapor Extraction (SVE) wells, 19 air sparging wells, and 20 dual-phase extraction wells. The remediation system utilizes SVE, groundwater pump and treat, and ozone sparging technologies.
2008: The treatment system initial startup occurred on December 22, 2007 and on March 7, 2008, ADEQ officially dedicated the site remediation system in Quartzsite, Arizona. This is the state's largest petroleum remediation system, and it marks the first time that ADEQ's Water Quality Assurance Revolving Fund (WQARF), and the UST program worked together on a joint project. Soil and groundwater remediation is ongoing at the site. Due to budget constraints, groundwater sampling was temporarily suspended at the site until additional funding was available.
The SVE was started in thermal mode and was converted to catalytic mode in June. As of December, 73,465 pounds of TPH, 1,143 pounds of benzene, and 3,122 pounds of MTBE had been removed by the SVE system. The GWE system processed 2,520,162 gallons of liquid and removed 151 pounds of TPH, 1.9 pounds of benzene, and 82 pounds of MTBE. The GWE system has also removed 233 gallons of free product. Prior to the start of the remediation system 55 gallons of free product had been manually bailed from the site.
2009: The influent vapors to the SVE decreased. The SVE system has removed (cumulatively) a total of 85,183 pounds of TPH, 1,229 pounds of benzene, and 3,322 pounds of MTBE as of December 23rd. The GWE system has processed (cumulatively) 5,508,613 gallons of liquid and removed 276 pounds of TPH, 2.1 pounds of benzene, and 140 pounds of MTBE. No free product was recovered during the year.
2010:The concentrations of influent vapors to the SVE system continue to decline. The SVE system removed approximately 8,310 pounds of TPH 24 pounds of benzene, and 85 pounds of MTBE.
Since beginning operations in late 2007, the SVE system has removed a total of approximately 93,660 pounds of TPH, 1,253 pounds of benzene, and 3,408 pounds of MTBE.
During this same time the GWE system processed 7,787,271 gallons of water and removed 335 pounds of TPH, 2.1 pounds of benzene, and 151 pounds of MTBE. No free product was recovered during the year.
The groundwater extraction system processed approximately 2,340,000 gallons of water and removed 83 pounds of TPH, 0.02 pounds of benzene, and 10 pounds of MTBE.
Quarterly groundwater monitoring resumed. Groundwater samples collected at the site indicate benzene is still present above the AWQS of 5.0 μg/l. The AWQS for MTBE has not been established. MTBE is also present at concentrations above the guidance level from ADEQ’s UST program of 20 μg/l.
2011: The concentrations of benzene and MTBE influent vapors to the SVE system continue to decline. Due to low recoveries of MTBE and benzene, ADEQ discontinued running the SVE system. The SVE system operated for approximately six months from January to June and removed approximately 1,687 pounds of TPH, 6 pounds of benzene, and 14 pounds of MTBE.
Since beginning operations in late 2007, the SVE system has removed a total of approximately 95,345 pounds of TPH, 1,259 pounds of benzene, and 3,422 pounds of MTBE.
During the year, the GWE system has processed 2,614,000 gallons of water and removed 232 pounds of TPH, 0.02 pounds of benzene, and 8 pounds of MTBE. No free product was recovered during the year.
Since beginning operations in late 2007 the GWE system has processed 10,662,720 gallons of water and removed 593 pounds of TPH, 2.15 pounds of benzene, and 160 pounds of MTBE. No free product was recovered during the year.
Annual groundwater monitoring at the site indicates only MTBE is still present above an AWQS or guidance level. The AWQS for MTBE has not been established. MTBE is present at concentrations above the guidance level from ADEQ’s UST program of 20 μg/l.
2013: One groundwater monitoring and sampling event was performed in June. MTBE concentrations in several wells are above the HBGL of 20 μg/l. The site was officially transferred to the UST Program Section, State Lead Unit as of July 1st. The UST case manager is Mark Rhoades who can be reached at (602) 771-4295.
2014: The Main Street and Kofa Avenue groundwater remediation system, once the location of Ted’s Truck Stop, has been permanently decommissioned. On June 19, the remediation systems were disassembled and transported to the Arizona Department of Administration surplus yard in Phoenix.
The only contaminant remaining above AWQS or HBGL is MTBE in groundwater. Contaminants of concern at the site may change as new data becomes available.
There are potential risks associated with exposure to gasoline and diesel fuels, principally from drinking contaminated groundwater. Cleanup activities are important to prevent further off-site migration. Drinking water is provided by the Town of Quartzsite water system and must meet all state and federal drinking water standards. If you live within one-half mile of the site and own a domestic well, you are encouraged to contact the project manager.
Subsurface soils at the site consist of two main units. Interbedded layers of well-cemented gravel, sand, silt, and clay exist from approximately ground surface to 70 feet below ground surface (bgs). Below 70 feet the soils consist of silty clay to clay, with the estimated clay percentage ranging from 50 percent to nearly 100 percent.
The groundwater system in the vicinity of Quartzsite consists of a shallow and a deep aquifer. The shallow aquifer is encountered at approximately 46 feet bgs. The depth to the deep aquifer is approximately 200-600 feet bgs. The hydrologic gradient of the shallow aquifer is typically north to northeast.
*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.