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CJevfogrcaf7echnks Inc. Page 4 Former Moresco Property Site Characterization Report R Project No.251.2 October 11, 1996 I. Before and between uses the whole collection assembly i t a e sample colle o s steam cleaned and nitrogen gas is flushed through the lines and pump and anequipment blank is collected to demonstrate effective decontamination. 2.2 Field Screening Methods Because every soil sample collected was not.selected for laboratory analysis, a screening process was used to gather additional information through field observation noting sediment type, especially grain size and clay content, moisture content. visible evidence of contamination, i.e., color change due to reduction of iron or discoloration from hydrocarbons and other pollutants, and the readings above background on a organic vapor meter (OVM). The OVM is a field portable photo ionization detector that uses a 10.2 eV lamp to,detect compounds with ionization potential belbw 10.2 eV (hydrocarbon range). The OVM will register concentrations as low as 0.1 ppm-(parts per million). The boring log illustrates these screening observations. 2.3 Soil Sample Analyses Selected samples were submitted for laboratory-All samples collected for possible analyses were relinquished to GeoAnalytical Laboratories of Modesto (DHS# E757) for analyses. These samples were tested for benzene, toluene, total xylenes and ethylbenzene (BTEX) by EPA method 8020, Total Petroleum Hydrocarbons as Gasoline (TPH-Gas):by EPA method 8015 modified, and one sample was tested far the fuel oxygenate compound MTBE. The detection limits for BTEX is 5.0 pg/kg (;ppb),' 1,0 mg/kg for TPH-Gas and 5.0 mg/kg. The positive MTBE detection was confirmed 'using mass spectroscopy EPA method 8260. Selected samples for geotechnical testing were submitted to Cooper Testing Laboratory in Mountain View, CA. 2.4 Borehole Closure F After successfully collecting the bottom' Bole -soil sample the soil borings were closed by pumping a neat cement grout (augmented with <4% bentonite) to grade using a tremie pipe and slurry pump. All grouting was conducted under the supervision of SJCPHSEHD personnel. 2.5 Disposition of Soil Cutting Soil cutting generated during the soil boring installation was added to the UST removal spoils stockpile. The stockpile was loaded on to a dump truck and transported by Manley and Sons Trucking under manifest to Forward Landfill where it was disposed.of (see attached disposal documentation).