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�� Cardno` November 3,2014 ATC Glover Well Destruction Report Shaping the Future 1.0 SITE DESCRIPTION The site is located west of Chrisman Road and north of West Eleventh Street, Tracy, California (Figure 1). The location is a mixed commercial, light industrial and agricultural area. The location ofth existil rM monitoring wells, building, former underground storage tanks(USTs), and other pertinent features are shown on Figure 2. The site is bound by railroad tracks to the north, several commercial and industrial properties to the east,West Eleventh Street and mixed commercial and industrial properties to the south, 7 and industrial and commercial properties to the west, followed by South Chrisman Road and agricultural properties. I 1.1 Site Background Two 500-gallon underground storage tanks (USTs) used to store gasoline were removed from the site on October 15, 1986. During removal of the USTs, petroleum product was noted in the southern UST excavation. Soil samples were collected from two feet below the bottom of the USTs, and petroleum hydrocarbon constituents and lead were detected in the soil samples. Smith Technology supervised the installation of three groundwater monitoring wells, MW-1, MW-2, and MW-3 on July 18, 1995. These wells were installed to facilitate groundwater monitoring and sampling at the site. Initial analytical results indicated the presence of elevated concentrations of petroleum hydrocarbons down gradient of the former gasoline USTs. Nine soil borings were advanced to depths up to 15 feet below ground surface (bgs) on September 24 and October 2, 1996. Analytical results of the soil and groundwater samples indicated the general extent of petroleum hydrocarbons and fuel oxygenates in soil and groundwater beneath the site. Soil vapor analytical results indicated the availability of oxygen, carbon dioxide, nitrogen, and methane in the vadose zone. Geophysical testing results of soil samples from the site indicated that the on-site receptor, the water supply well, would not likely be affected by the petroleum hydrocarbon plume in groundwater within the next 20 years, in the worst case. Three additional groundwater monitoring wells (MW-4, MW-5, and MW-6)were installed at the site on March 9, 1999. Analytical results of the soil and groundwater samples collected at the site indicated the lateral extent of impacted soil and groundwater had been defined. At the request of the San Joaquin County Environmental Health Department(SJCEHD), ATC evaluated contaminant migration potential of hydrocarbon affected soil and groundwater at the site using the EPA's BIOSCREEN (v.1.4) software program. The results of the computer modeling indicated the petroleum impacted soil and groundwater at the site do not appear to be an immediate and significant threat to human health or the environment. The computer modeling results are presented in ATC's Addendum to Additional Site Evaluation and Request for No Further Action for Fayette Manufacturing Corporation, dated November 4, 2002. On April 5 and 8, 2004, an additional subsurface investigation consisting of four soil borings (GP-1, GP- 2, GP-3, and CPT-1)was conducted to evaluate the vertical extent of impacted soil in the vicinity of the former USTs and possible lateral migration of impacted groundwater between wells MW-4 and MW-5. Analytical results confirmed that dissolved phase petroleum hydrocarbons had migrated between wells MW-4 and MW-5. 2