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Mr. James L.L. Barton • 0 Former Countryside Market
<br /> October 19, 2011 Stockton, California
<br /> Page 2 of 6
<br /> (EDB), and total lead. TPHg was detected in all four samples at concentrations ranging from
<br /> 770 to 6,500 milligrams per kilogram (mg/kg). The excavated soil was subsequently returned to
<br /> the excavation, and no investigation was performed.
<br /> In October 1995, approximately 40 cubic yards of hydrocarbon-affected soil was excavated and
<br /> replaced with clean backfill. The excavation reportedly reached depths of between 11 and 13 ft-
<br /> bgs. Soil sample CM-1-13 collected from the bottom of the excavation yielded TPHg, benzene,
<br /> toluene, ethyl benzene, and total xylenes at concentrations of 14,000 mg/kg, ND<0.005 mg/kg,
<br /> 37 mg/kg, 78 mg/kg, and 340 mg/kg, respectively. The excavation was backfilled with clean
<br /> stockpiled soil and clean pea gravel.
<br /> In August 2001, two soil borings (CM-1 and CM-2) were completed on-Site at locations shown
<br /> on Figure 2. Boring CM-1, located between the dispenser island and the former USTs, was
<br /> advanced to 90 feet bgs. Boring CM-2, located approximately 25 feet south of CM-1, was
<br /> completed to a depth of 50 feet bgs. During the completion of boring CM-1 groundwater was
<br /> encountered at a depth of approximately 90 feet bgs. TPHg was detected above the laboratory
<br /> reporting limit in all eight soil samples collected from boring CM-1, including a maximum
<br /> detection reported concentration of 15,000 mg/kg in the sample collected from 50 feet bgs.
<br /> Boring CM-2 yielded TPHg above the laboratory reporting limit in one of four analyzed soil
<br /> samples at a concentration of 590 mg/kg in the sample collected from50 feet bgs.
<br /> In addition, during the August 2001 environmental investigation one grab groundwater sample
<br /> was collected from boring CM-1 and analyzed for TPHg, BTEX compounds, MtBE, tertiary butyl
<br /> alcohol (TBA), diisopropyl ether (DIPE), ethyl tertiary butyl ether (EtBE), tertiary amyl methyl
<br /> ether (TAME), EDB, and 1,2-dichloroethene (1,2-DCA). TPHg, BTEX compounds, and TBA
<br /> were detected above the laboratory reporting limits at concentrations of 62,000 micrograms per
<br /> liter (pg/L), 5,500 pg/L, 10,000 pg/L, 2,900 pg/L, 8,300 pg/L, and 230 pg/L, respectively. No
<br /> other analytes were detected above the laboratory reporting limits. Historical soil and
<br /> groundwater analytical results are presented in Table 1.
<br /> PRE-FIELD ACTIVITIES
<br /> Prior to work at the Site, the following activities will be completed:
<br /> • Approval of this Work Plan will be obtained from the CRWQCB;
<br /> • A Site-specific health and safety plan (HASP) will be prepared in accordance with OSHA
<br /> regulations 29 CFR 1910.120;
<br /> • The proposed drilling locations will be demarcated on the Site;
<br /> • Well installation permits will be obtained from the San Joaquin County Department of
<br /> Environmental Health (SJCDEH);
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