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&W &. 01 December 2006 AGE-NC Project No. 98-0440 Page 5 of 6 r Figure 3. Based on the estimates of petroleum hydrocarbon soil that was removed from the site, approximately 471 lbs or 75 gal of gasoline remain in soil at the site. The mass and volume calculations are presented in Appendix E. 4.0. SUMMARY AND CONCLUSIONS ,! Based on the data collected from the site, AGE finds: • TPH-g was detected in all the soil samples at concentrations ranging from 1.7 mg/kg in soil sample NF-14 to 80 mg/kg (CB-14). TPH-d was detected in 4 of the soil samples at concentrations ranging from 90 mg/kg (B-16) to 1,100 mg/kg (SP-5-9). Various BTEX constituents were detected in all the soil samples at concentrations as high as 0.11 mg/kg a- benzene (BN-16), 0.016 mg/kg toluene (SF-15), 16 mg/kg (SF-16) and 8.4 mg/kg xylenes (SF-15). Table 1 contains a summary of soil excavation analytical results. The low concentrations of petroleum hydrocarbons in the majority of soil samples collected from the walls and floor of the excavation suggests that a portion of the most significantly impacted soil was removed during excavation activities. Based on the low concentration ,r from excavation soil sample NF-14(1.7 mg/kg),it would appear a majority of impacted soil was removed from the north side of the excavation and former UST areas. However, impacted soil remains at the site to the south and east of the excavation and vertically beyond .� the limits of the excavation. • Based on the analytical results of soil samples collected during the excavation, AGE calculates that approximately 279 lbs or 45 gal of gasoline were removed during excavation in May and June 2006. The mass and volume calculations are presented in Appendix E. • AGE calculates that approximately 471 lbs or 75 gal of gasoline remain in soil at the site. Approximately 38%of petroleum hydrocarbon-impacted soil was removed during the May and June 2006 excavation. The mass and volume calculations are presented in Appendix F. 5.0. RECOMMENDATIONS Based on the results of site investigation activities to date, AGE recommends continued ground water monitoring and sampling as discussed in the Soil Remediation Work Plan and as directed by *� EHD letter dated 13 November 2006. L. �. Advanced GeoEnvironmental,Inc.