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`'' Cr¢ological7"erluucslnc. ti-/ � Site Characterization Report Page 3 Project No. 1218.2 ,., February 9,2006 Up to four soil samples from each boring were submitted for laboratory analysis. A screening process was used to gather information through field observations. The field screening included: • Odor (measured via OVM, a portable photo ionization detector that uses a 10.6 eV lamp to detect compounds with ionization potential below 10.6 eV). LN • 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) Details on the geology encountered during the direct push survey, as well as the field �. observations, are included in Section 3.1, Geology and Field Observations. See Appendix C,Boring Logs for more information. 2.1.2 Soil Laboratory Analyses The soil samples collected were delivered to Castle Analytical Laboratory (California ELAP .r No. 2480), of Atwater, California, for the following analyses: • Benzene, toluene, ethyl benzene and xylene (BTEX) by EPA method 8015 • Gasoline range petroleum hydrocarbons (TPH-G)by EPA method 8015 • Diesel range petroleum hydrocarbons (TEPH-D) by EPA method 8015 The detection limits for these compounds are listed in the laboratory data sheets included in Appendix B and summarized in Table 1 of Appendix A. A Chain of Custody was completed for all samples collected and tracked to ensure sample integrity. 2.2 Groundwater Sampling No groundwater sampling was originally proposed in the investigation. However, the SIC/EHD required that groundwater samples be obtained in order to receive site closure concurrence. To investigate the presence of petroleum hydrocarbons in the groundwater at this site, a grab groundwater sample was obtained from the SB-3 borehole. GTI originally intended to obtain a groundwater sample from each borehole but the shallow rod refusal in `a the first borehole precluded obtaining a water sample from each hole within the scope of work budgeted. `' 2.2.1 Groundwater Sampling Procedure RSI staff advanced the rods to 58.5 feet bgs in SB-3 where a wet sand was encountered. The hole did not contain enough water to sample by small diameter, stainless steel bailer. It was 460 decided to pull the rods back 8 feet and let the hole sit through a lunch break. After lunch (20 minutes) the hole contained water to a static depth of approximately 50 feet bgs. Groundwater was carefully poured from the bailer into VOA vials and an amber one-liter `r bottle. The VOA vials were capped, inverted, tapped, and checked for headspace bubbles. k..