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Geologual Technuslnc Page 3 George's Service Soil Excavation Report Project No 425 3 January 28,2002 ' drainpipes were installed at the west and east ends of the excavation site to a depth of 10- feet bgs Pea gravel was used to fill the excavation pit to 1 5 feet bgs and compacted with a ' vibrating compactor Class 2 base-rock was used to fill the pit to 4-inches bgs and was capped with asphalt after compaction ' Field Observations - The northern wall of the excavation pit was primarily tight plastic clay The clay contained a 12 foot long by 2-foot thick lens of soft sugary sand located about 6 feet bgs, which pinched out at both ends The southern wall was silty clay/clayey silt The western wall ' was clay and silt but also showed some large rocks In the eastern half of the excavation, contamination started a few feet below ground surface and extended deeper than 12-feet bgs In the western half of the excavation, the contamination was below 5-feet bgs and extended to greater then 12-feet bgs ' Groundwater was at approximately 11-feet bgs Sidewall samples were collected from six locations around the excavation pit by driving a clean brass tube into the soil The end's of ' the tubes were covered with Teflon and plastic caps The tubes were labeled, a chain of custody was filled out and the samples submitted to Sherwood Laboratories in Hilmar for analysis Figure 1 is a map showing excavation sample locations ' Two photographs of the excavation are presented in Appendix D Monitoring Well Damage and Repair • The casing on MW-102 was bent during the excavation on July 24" The casing was repaired by GTI on the 25" by cutting off the bent section at approximately 11-feet bgs and gluing in a riser • The well casing of MW-5 was cracked at approximately 2 feet bgs The casing was cut off at two feet bgs and an extension was glued into place ' • The top of casing of MW-202 was damaged during the excavation on July 25, 2001 The casing was trimmed and the cap was replaced on MW-202 In accordance to A132886, on December 21, 2001, all the monitoring and domestic wells ' were surveyed Soil Analyses ' The average TPH-gasoline for the excavation was 4,114 mg/Kg Samples collected at the SE Sidewall and SW Sidewall locations had the highest concentrations at 11,800 and 26,200 mg/Kg respectively These two samples also had the highest concentrations of MTBE at 38,500 and 4,920 ug/Kg respectively, however the MTBE results were performed by EPA ' method 8020 A summary data table of the soil data is included as Table 1 in Appendix A Laboratory ' Data Sheets are included in Appendix B Soil Disposal The contaminated soil was piled on plastic and covered with plastic as required by San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) The stockpile remained covered on site until October 31, 2001