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' contractor (Spectrum Exploration of Stockton, California) who placed the piezometer on February 28, 1991 as part of the preliminary site assessment Excavation was limited on the north end due to the presence of the restroom structure Sample SW-13 was taken at a depth of eight feet below surface grade after all remaining stained soils were removed to the edge of the structure. Further excavation would have undermined the stability of the structure. Concentration of TPH as diesel in SW-13 was reported as 40 mg/kg and BTEX was reported as non-defect. 3.5 Confirmation Analytical Testing within Excavation Final confirmation soil samples were collected in the presence of Mary Meays of the SJCPHS Final confirmation soil samples were obtained from the sods immediately ' above the groundwater along the excavation perimeter at intervals of 20 lineal feet The results of confirmation testing of samples SW-2, SW-4, SW-8, SW-9, SW-10, SW-11 and SW-12 were reported as non-detectable for concentrations of TPH as ' diesel and BTEX. The results of confirmation sample SW-3 were reported as concentrations of TPH as diesel of 1.7 mg/Kg and was subsequently over excavated by a distance of 2 to 3 feet to remove remaining hydrocarbons in that location The ' results of confirmation sample SW-13 were reported as concentrations of TPH as diesel of 40 mg/Kg but was not able to be over excavated due to the presence of the restroom structure. No visually grey stained soils remain at this location 3.6 Soil Stockpiles Excavated soils were stockpiled on-site adjacent to the existing stockpile in a location as shown on Figure 2. Two new stockpiles were created, one containing saturated soils from below the groundwater which infiltrated the excavation and one containing soils from above the saturated zone The saturated soils were placed within a berm that was covered with plastic to contain the water All three ' stockpiles are situated on plastic and are covered with plastic. Stockpiled soils are not being remediated at this time A plan for the disposal and/or remediation of the stockpiles will be submitted after a cost study is completed 4.0 GROUNDWATER EVALUATION ' Groundwater remediation was not addressed at this project stage of the ro ect Duringthe excavation as requested by the SJCPHS a groundwater grab sample was taken from the excavation In groundwater that seeped into the excavation on December 9-11, 1991, there was a visual presence of floating petroleum hydrocarbons Concentrations of TPH as diesel of 72 mg/L and non-detectable concentrations of ' BTEX were reported for this sample 4 ' BRUNSING ASSOCIATES, INC. s