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AANARK Z� KA 1992 Third Quarter Report,Site Code 1178 City of Stockton,Police Facility October 14, 1992 Page 3 In order to remove impacted soils from the northern portion of the excavation, the vapor recovery line was disconnected and removed. The vapor recovery line was capped at both ends to prevent leakage. Field observations and PID readings indicated the presence of possible contaminant source near the south wall of the police building. As the excavation proceeded northward, a leaking product line delivering unleaded gasoline was discovered approximately 2.7 feet south of the concrete walkway on the south side of the building. A portion of the product line was removed to allow excavation of impacted soils beneath the line. The excavation was limited to the north by the building and concrete walkway. The product line leak was repaired by Falcon Energy under a separate scope of work. The product and vapor line repair, and subsequent pressure testing, was performed under the regulatory guidance of Ms. Pamela S. Violett of PHSIEHD. Soils encountered beneath the site during excavation activities consisted of grayish brown silt to a depth of approximately 6.5 to 8 feet below grade, and grayish brown stiff clay underlying the silt to approximately 13 feet below grade, the maximum depth of the excavation. Visible hydrocarbon impaction of soil was evident to a depth of approximately 6 to 6.5 feet below grade. PID measurements detected vapors intermittently to approximately 8 feet below grade. As PID readings and field observations (i.e., odor, discoloration) defined the horizontal and vertical limits of the contaminated soil, 11 confirmation soil samples were collected under the regulatory guidance of Ms. Mary Meays of PHSIEHD. Sample locations are shown on Figure 3. A summary of samples collected, sampling dates, and analytical results are summarized in Table 2. The eastern-most portion of the excavation pit was backfilled with clean sand on a daily basis to allow vehicle access to the prison bay entrance. The clean fill was re-excavated each day as necessary to resume the excavation. All suspected hydrocarbon impacted soils and clean fill excavated from the site were transported to the City of Stockton Municipal Service Center where they were placed on asphalt and covered by 6 mil plastic sheeting. Approximately 305 yards of native and backfilled soil were excavated from the subject site and stockpiled at the City Service Center. Logs of soils delivered to the Service Center from the Stockton Police Facility are included in Attachment 1. Subsequent to excavation and soil sample collection, the open excavation was backfilled with clean engineered sand under the requirements set forth by the City of Stockton Public Works Department. QRTLY RPT\QR090292.FNL