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December 1; 1994 <br /> Page 2 - <br /> SCOPE,OF'WORK <br /> Exploratory Test Pits <br /> In order to further delineate the lateral extent of hydrocarbon-impacted soils, PACIFIC <br /> excavated 13 exploratory test pits in the locations indicated on Figure 2. Field work was <br /> performed on August 25, 1994. Field activities were observed by a representative,of the <br /> SJCHSD. <br /> The work was performed using a backhoe operated by a licensed contractor(Paradiso <br /> Construction Company). The exploratory excavations were approximately 18-inches <br /> wide, I0-feet long, and 10 to 15 feet deep. Soils exposed in`the test pits were logged by <br /> a PACIFIC geologist in accordance with the Unified Soil Classification System to <br /> provide further subsurface characterization. In addition, headspace readings were <br /> recorded throughout each of the test pits. The test pits were excavated as described in <br /> the investigation procedures section of this report(Attachment A). Upon completion of <br /> sampling activities, the test pits were backfilled with native soils. Geologic logs of the <br /> test pits are presented in Attachment A. <br /> Soil and groundwater samples were collected from the exploratory excavations and <br /> preserved for chemical analysis. Soil samples were analyzed for total oil and grease <br /> (TOG), total petroleum hydrocarbons calculated as gasoline(TPH-g), and TPH <br /> . calculated as diesel(TPH-d), and benzene, toluene, ethylbenzene, and total xylenes <br /> (BTEX compounds). In addition, samples were analyzed for lead using an extraction <br /> method for the soluble threshold limit concentration. Groundwater samples were <br /> analyzed for total purgeable petroleum hydrocarbons calculated as gasoline(TPPH-g) <br /> and BTEX compounds. Certified analytical reports and chain-of-custody documentation <br /> are presented as Attachment B. <br /> Biological Assessment and Pilot Landfarming <br /> Unocal Environmental Technologies Group is currently performing a biological <br /> assessment on soil samples collected from test pit TP-11. When initial soil parameters <br /> have been established, the feasibility for land£arming (i.e., nutrient treatment and soil <br /> tilling)will be evaluated. A pilot landfamling'experiment is being conducted on site. <br /> FINDINGS <br /> Subsurface Conditions <br /> The soil stratigraphy encountered in the test pits during this investigation appears to be <br /> relatively uniform across the site and correlates with earth materials encountered in soil <br /> borings drilled during previous site investigations. Deposits of silts and'cIays were <br /> • encountered in all test pits to 8 to 15 feet below ground surface(bgs), the maximum <br /> 3100011B/REPORT <br />