ARCHIVED REPORTS_REMEDIATION COMPLETION REPORT

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3.0 FIELD ACTIVITIES the final verification samples discussed below,sample identification was assigned based on the location and depth of the sample and the order in which the samples were collected. Sample identifications and locations were assigned on the basis of a"sample north" designation,running parallel to the eastern and western fence lines, and a"sample west," running parallel to the northern and southern fenceline (Figure 4).Approximate sample locations are shown on Figure 4 and referenced on Table 2. TPH-g and BTEX were below their respective detection limits in both hand auger samples. TPH-d was non-detect in sample 20-14.5W-115N-5.OHA at 5 feet bgs.The only detected concentration of TPH-d was 190 mg/kg in sample 20-14.5W-115N-9.5-HA at 9.5 feet bgs. TPH-mo was detected at 18 mg/kg in sample 20-14.5W-115N-5.OHA at 5 feet bgs,and was non-detect in the other hand auger sample. This area was not excavated based on access limitations due to the proximity of the active fiber optic line and due to property boundary issues. The analytical results and COC documents are presented in Table 2 and Appendix E, respectively. As with the hand auger samples,BTEX was non-detect for both samples collected from the test pit locations.TPH-g was non-detect in one sample and was reported at a concentration of 21 mg/kg in sample 20-42W-105N-5B at 5 feet bgs.TPH-d was detected at concentrations of 2,300 and 44 mg/kg in test pit samples 20-42W-105N-5B and 20-42W-11ON-5B,both at 5 feet bgs,respectively.TPH-mo was detected at 46 mg/kg in sample 20-42W-11ON-5B at 5 feet bgs,but was non-detect in the other sample.The soil in both of these test pit areas was removed during excavation activities based on this analytical data.The analytical results and COC documents are presented in Table 2 and Appendix E,respectively. 3.7.3 Verification Sampling Verification soil samples from the bottom and sidewalls of the excavation were collected and analyzed to document soil conditions prior to backfilling. The excavation was designed to remove the primary source of petroleum hydrocarbons to groundwater within the constraints of the excavation boundaries. A total of 33 final verification samples were collected from the excavation boundaries;16 were collected from the perimeter sidewalls and 17 from the base of the excavation.Sidewall samples were collected during excavation activities using the same methods described in Section 3.5.Sidewall samples were collected at depths of approximately 5 feet bgs and spaced laterally to result in one sample for every 20 linear feet.Due to excavation constraints as described in Section 3.6, all sidewall samples were considered final and no additional samples were collected. Seventeen bottom samples were collected to provide approximately one base sample for every 20-foot by 20-foot area. Actual sample locations were determined in the field based on observed removal of petroleum staining and/or odor. Soil samples were analyzed for the same parameters outlined in Section 3.7.2. Table 3 summarizes verification soil sample analytical results.Analytical reports and COC documents are provided in Appendix E. Analytical results for BTEX and TPH in soil were evaluated to assess whether further excavation was needed prior to backfilling the excavation areas. SF01(THORNTON COMPLETION REPORT_621-05.DOC) 3.5