SITE INFORMATION AND CORRESPONDENCE

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Spingolo Trucking 10'' - 3 - `"'" 25 November 2014 1011 N. Broadway Ave., Stockton San Joaquin County Table 1: Maximum soil concentrations are in milligrams per kilogram (mg/kg). Date TPHg TPHd TPHm B T E X 1,2-DCA MTBE TBA 0 4/92 720 NA NA <1 <10 <10 15 NA NA NA 10/2001 130 4,700 1,400 0.019 <0.005 0.11 0.12 <5 <5 <25 3/2006 <1 69 NA <0.005 0.018 0.026 0.058 <0.005 <0.005 <0.1 6/2007 18 11,000 NA 0.32 <0.005 0.075 0.35 NA NA NA TPHg =total petroleum hydrocarbons as gasoline TPHd = TPH as diesel TPHmo = TPH as motor oil B = benzene T= toluene E = ethylbenzene X = xylenes Pb =total Lead MTBE = methyl tert butyl ether 1 = confirmation sample NA = not analyzed Table 2: Maximum groundwater concentrations are in micrograms per Liter (ug/L). Date TPHg TPHd TPHm B T E X 1, 2- MTBE TBA o DCA 10/20011 <50 200 NA <0.5 1.0 <0.5 <0.5 <1 <1 8.1 4/20062 <50 <50 NA <0.5 <0.5 <0.5 <0.6 <0.5 <1 <10 7/2006 <50 <50 NA <0.5 <0.5 <0.5 <0.6 <0.5 <1 <10 10/2006 <50 <50 NA <0.5 <0.5 <0.5 <0.6 <0.5 <1 <10 4/2007 <50 1 <50 NA L <0.5 <0.5 <0.5 <0.6 <0.5 <1 <10 1 = grab groundwater sample 1, 2-DCA = 1, 2-dichloroethane EDB = ethylene dibromide 10)The data show that petroleum hydrocarbons are adequately delineated in soil and non-detect in groundwater. Active remediation was not required by the regulatory agencies. 11)The Site passed the State Water Resources Control Board Low Threat Closure Policy (see LTCP below). The residual soil contamination is limited in extent (P-1, P-2, P-5 and P-6) and exceeds the San Francisco Bay Region 2 Environmental Screening Levels for gross contamination (TPHd) and direct contact (TPHd) at 15' bgs, which is below typical utility worker depth. The Site uses municipal water and nearby domestic wells are not threatened (see Sensitive Receptor Survey below). Residual petroleum hydrocarbons in soil pose a minimal threat to human health or the environment. Due to the distance from the USTs to Site office (over 70'), the open bay construction of the shop next to the USTs, and the large unpaved trucking yard, Staff did not require a soil vapor survey. Land use (commercial) is not expected to change in the foreseeable future. Groundwater monitoring showed that water quality goals (WQGs) were not exceeded. 12) A 2005 sensitive receptor survey identified thirty six (36) domestic or unknown use supply wells located within 2000' of the site in a commercial and residential area of Stockton (Table 3). The distance to the closest wells (Figures 3 and 5), onsite well (#28 600' east of the USTs) and to 1036 Broadway's well (#29 800' east of USTs) are not accurate as stated in Table 3, as the boundary of the entire 40+ acres was used as the beginning point to measure to the offsite wells, and some directions are inaccurate as well. Well #28's pump is out of service and the Site is on municipal water. Well #29 was sampled by Staff in November 2010 and all water results were non-detect. The 36 supply wells are not threatened by the TPH release, as petroleum hydrocarbons were not detected after four quarters of groundwater monitoring.