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Ralappan&Meyer • • Date:3/3/99 Arch Road/Highway 99 Page: 7 ' 3.0 DEVIATIONS FROM THE WORK PLAN ' Because of a malfunction with the organic vapor meter (OVM) headspace in the soil samples could not be analyzed in the field for the presence of volatile organic compounds. However, visual field observations were logged. ' The objective of the investigation was to collect soil samples from 10 and 15 feet bgs 1 from each boring. However, refusal (hardpan) was encountered at approximately eight feet bgs in five soil borings (B-5, B-6, B-7, B-8, and B-9). Soil samples were not collected from B-5. Soil samples were collected at eight feet bgs from borings B-7 and ' B-8. A soil sample was collected at nine feet bgs (refusal) from B-6. Soil samples were collected from six and eight feet bgs in B-9. Soil samples from the remaining borings (B- 1 through B-4 and B-10)were collected from 10 and 15 feet bgs. ' Borings B-5, B-7, B-8, and B-9 were located within the anomaly identified from the VMG survey. Therefore, it appears that the anomaly was the result of the hardpan. 1 4.0 ANALYTICAL RESULTS 4.1 Shallow Soil Borings ' Results of shallow soil borings indicated very low levels of lead (up to 13 milligrams/kilogram [mg/kg]). The California-Modified Preliminary Remedial Goal (PRG) for lead in soil in a residential area is 130 mg/kg and 1,000 mg/kg for an 1 industrial area. Results of the Arch Road sampling event are significantly below these PRGs. TPH-D results indicated very low concentrations in every sample collected from the soil borings, ranging from 1.1 mg/kg to 36 mg/kg (detected in B-10-10). There are currently no regulatory action levels for TPH-D. Because the concentrations of diesel in the soil ' samples were consistent throughout the site, there does not appear to be a source area (i.e., a leaking underground storage tank). Based on the sampling results the TPH-D contamination appears to originate from diesel trucks which use the vacant lot as a turn- around. TPH-G, and BTEX were not detected above the instrument detection limit in the shallow ' soil borings. Refer to Table 1 for a summary of the shallow soil boring results and Appendix C for laboratory results. ' 4.2 Surface Soil Samples Results of the surface soil samples indicate very low levels of lead in 17 of the 29 ' environmental samples collected. Concentrations ranged from none detected (ND) to 85 mg/kg in S-IA (the duplicate sample of S-1). These results are significantly below the U.S. EPA industrial PRG (1,000 mg/kg) and are also below the California-Modified PRG ' (130 mg/kg). Refer to Table 2 for a summary of surface soil sampling results and Appendix C for laboratory results. R&M/Arch Rd/43-00066762.00.5000