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P R Sacramento Insulation Contractors Project No. EOC-96-028 ethylbenzene and toluene analysis, and 0.015 mg/kg for xylenes analysis. Copies of the analytical data are presented in Appendix C. � e rt After completing the excavation of the boring to a depth of approximately 60 feet bgs, the hollow-stem augers were withdrawn to a depth of approximately 53 feet bgs, and drilling activities were temporarily suspended to allow for groundwater recharge into the borehole. After waiting approximately 30 minutes, groundwater was measured with a Solinst water level indicator at a depth of approximately 56 feet bgs. Borehole groundwater sample SICS-B1-Water was collected from the annulus of the augers using a Voss disposable bailer. The bailer was lowered to a few inches below the groundwater surface; withdrawn from inside the augers, and the contents decanted into two 40 milliliter VOA vials. The groundwater sample was then j submitted to the onsite mobile laboratory for TPH and BTEX analysis. The groundwater sample I collected from this boring did not contain detectable concentrations of TPH or BTEX. The 1 laboratory reported detection limits of 50 micrograms per liter(Ng/L) for TPH gasoline; 500 pg/L i for TPH diesel analysis; 0.5 pg/L for benzene, ethylbenzene and toluene analysis, and 1.5 pg/L ! for xylenes analysis. A log of the boring is provided in Appendix B with a summary of the soil sample depths and analytical results presented in Table 1. Copies of the analytical results are f presented in Appendix C. Mr. Knoll was on site during the excavation of Boring B1 and discussed the analysis of the soil samples collected from Boring B1 and indicated his agreement with the soil and groundwater samples chosen for TPH and BTEX analysis. Additionally, Mr. Knoll indicated that a depth to groundwater of approximately 56 feet bgs on the site was consistent with other information obtained from areas adjacent to the site. EOC personnel and Mr. Knoll agreed that the location of Boring B1 would provide good coverage ` of soil and groundwater conditions in the area of the former location of the UST; however, a t� visual survey of other areas of the site was conducted in an attempt to identify other possible locations of the former UST excavation. While performing a survey of the site, Mr. Knoll observed a cut off vent pipe adjacent to the building that appeared to lead to a patch in the asphalt, closer to the warehouse building than Boring B1. EOC and Mr. Knoll agreed to excavate Boring 62 in the center of the asphalt patch discovered by Mr. Knoll. I Mr. Knoll left the site and returned during the excavation of Boring B2. EOC relayed to Mr. Knoll the remaining analytical results from the soil and groundwater samples obtained from Boring 61. Based on those results, Mr. Knoll indicated that he would require only one additional boring (Boring B2) in the center of the asphalt patch, and that since the groundwater sample collected from Boring B1 did not contain detectable concentrations of TPH or BTEX, another borehole groundwater sample was unnecessary. ( Boring B2 was advanced at a location approximately 48 feet south and 6 feet east of the northeast comer of the warehouse. With Mr. Knoll's concurrence, the boring was excavated to a ( depth of approximately 36.5 feet bgs. Seven soil samples were collected from this boring at approximate 5 foot intervals beginning at a depth of 5 feet bgs with 4 of the soil samples submitted to the onsite mobile laboratory for chemical analysis. Soil samples B2-3, B2-4, B2-5, and B2-6, collected from 15 feet, 20 feet, 25 feet, and 30 feet bgs, respectively, were analyzed for the presence of TPH and BTEX. Detectable concentrations of these compounds were not measured in these four soil samples. A log of the boring is provided in Appendix B with a summary of the soil sample depths and analytical results presented in Table 1. Copies of the analytical data are presented in Appendix C. EnvirOmega Consultants 3 December 11,1996 1