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AZURE ENVIRONMENTAL 2.0 CONFIRMATION SOIL SAMPLING ' 2.1 Soil Sampling Methods and Procedures To obtain representative data of petroleum hydrocarbon concentrations remaining in the treatment ' cell soil, eight soil samples (SB-1 through SB-8) were collected on a grid pattern superimposed on the treatment cell (Figure 2) The soil samples were collected at depths between 2 and 3 feet ' below grade Additionally, two soil samples (SB-9 and SB-10) were collected from the soil berm that forms the outer boundary of the treatment cell The samples were collected at a depth of 2 5 feet below the top of the berm ' The soil samples were collected using hand auger equipment and a clean shovel The sampling equipment was decontaminated prior to reuse at each sampling location The soil samples selected for laboratory analysis were collected in glass bars, labeled and then placed in an ice- chilled cooler for transport to the laboratory All work was performed under the direction of a California Registered Geologist ' 2.2 Soil Sample Analysis Results ' Soil samples collected at locations SBA through SB-10 were submitted to a California state- certified laboratory and analyzed for total petroleum hydrocarbon (TPH) analysis characterized as gasoline and diesel (EPA Method 8015/5030) and BTEX compounds (EPA Method 8020), including methyl t-butyl ether (MTBE) Sample analysis results are summarized in Table 1, laboratory analysis certificates are presented in Appendix A Sample analysis results from borings SBA through SB-10 indicate that TPH as gasoline, BTEX compounds, and MTBE were not detected in soil samples (Table 1) Only TPH as diesel at relatively low concentrations between 5 mg/kg and 53 mg/kg were detected 1n the soil samples Soil sampling results for TPH as diesel are illustrated in Figure 2 The distribution of TPHd appears to be random within the soil treatment cell, with the highest TPHd ' concentration (53 mg/kg) detected at the central area of the treatment cell and the lowest concentration (5 mg/kg) detected at the soil berm 3.0 RECOMMENDATION FOR SOIL TREATMENT CELL CLOSURE I Results of soil sampling indicate only relatively low concentrations of total petroleum hydrocarbons as diesel remain in treatment cell soil Diesel concentrations in treatment cell soil are below concentration levels that would be considered a potential threat to further degradation of ground-water quality at the Site Residual hydrocarbons in soil are expected to continue to be remediated as a result of biodegradation and other attenuation processes Based on the soil sampling results described above, it appears that adequate soil treatment has been completed and no further remedial actions are recommended for treatment cell soil. Therefore, it is requested that the soil treatment cell be approved for closure After receiving � approval from the SJCPHS for treatment cell closure, Manna Pro plans to decommission the 2