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• SNITH • approximately 2 and 15 feet below grade Excavation continued until field evidence indicated that contamination was no longer present and/or further excavation was impracticable and unsafe The excavation was limited the northwest by a underground utilities (including a high pressure four-inch water main) and to the northeast by a postal building While excavating along the eastern extent of the tank pit, an abandoned septic tank was dislodged from its position and removed from the excavation Although an organic odor was noted in the soils beneath the septic tank, there was no obvious indication petroleum products had ever been channeled to the tank During excavation activities, confirmation samples were collected under the direction of Ms Mary Meays of PHS/EHD A total of 13 sidewall and 2 bottom samples were collected from the excavation Samples were collected from the excavator bucket at least three inches below the surface of the soil The samples were collected into prewashed brass liners Each liner was sealed with Teflon sheets and plastic caps, placed in air-tight bags, and preserved on ice pending shipment to Argon Laboratories (DHS Cert #1873) in Ceres, California Soil samples were transported under chain of custody to the laboratory for analysis of benzene, toluene, ethyl benzene, and xylenes (BTEX), and TPHg by EPA methods 8015/8020 Several samples were also analyzed for total lead by EPA method 6010 Based upon field observation, FID readings, and/or preliminary laboratory analysis, a total of I 1 soil samples were analyzed in the laboratory The soil sampling locations for the analyzed samples are depicted on Figure 3 The descriptions for these samples are included in Attachment I Excavated petroleum hydrocarbon impacted soil was underlain and covered with 6-mil plastic sheeting pending laboratory analysis Stockpiled soil samples were collected and analyzed for BTEX, TPHg and total lead by the methods described above Fourteen 2-sleeve composite samples were collected from the stockpiled soil (approximately one per 100 cubic yards of soil) Sample locations are shown on Figure 3 During the excavation process groundwater was initially encountered at a depth of approximately 11 to 15 feet and stabilized at approximately 10 feet below the ground surface Prior to the open excavation being backfilled with imported self compacting material, approximately 10,000 gallons of was pumped from the open excavation into an on-site storage tank for containment and treatment A water sample was collected by lowering a disposable bailer into the water in the tank The sample was submitted to Argon Laboratories for analysis BTEX and TPHg by EPA methods 8015/8020 Analytical results for groundwater are included in Table 2 Analytical Results A review of confirmation soil sample results indicates the residual petroleum hydrocarbons in the southwest, south, and eastern portions of the excavation have been generally removed in the ' lateral direction Low concentrations of toluene and xylenes were detected marginally above the 1500811SXR-0995 DOC 3