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~ Ms. Connie Davis/Aggregate Industries - F Street January 2002 QMR Project Number 1001018 Pl1RflGON February 27, 2002 Page 2 Contaminated soil was excavated from the spill area between May 8, 2001 and May 31, 2001 and stockpiled at the site for use in asphalt paving mix. The approximate extent of the abatement excavation which was completed at the site is shown on Figures 3a and 4. Approximately 103,000 gallons of groundwater/free-phase product mixture was also pumped from the excavation during the abatement activities. Soil and groundwater sample results from the abatement excavation were discussed in the July 6, 2001 Soil and Groundwater Abatement Report. Installation of groundwater monitoring wells was performed at the site in July 2001 and October 2001 to obtain information regarding groundwater quality at the site. Information regarding the assessment activities was summarized in the October 9, 2001 Site Characterization Report (SCR) and October 2001 Quarterly Monitoring Report dated November 16, 2001. The groundwater monitoring program proposed in the SCR included the sampling of six (6) wells (MW-1 through MW-4, EW-1 and a proposed well) for benzene-toluene-ethylbenzene-xylenes (BTEX) and total extractable petroleum hydrocarbon (TEPH) analyses. 2.GEOHYDROLOGY Groundwater elevations in wells MW-1 through MW-5 and EW-1 were measured by Paragon prior to sampling on January 29, 2002. Groundwater elevation data for the site is summarized in Table 1 which is attached to this report. As seen from Table 1, groundwater was observed at depths ranging from approximately 7.4 to 25.5 feet below grade during the January 2002 sampling event. Free-phase product was not observed during the January 2002 sampling episode. Piezometric surface diagrams for groundwater elevations observed on January 29, 2002 are attached to this report as Figures 3 and 3a. The piezometric surface for the overall site, including wells OW-1, OW-2 and OW-4, is shown on Figure 3 while the piezometric surface in the vicinity of the spill area is shown on Figure 3a. The piezometric surfaces were estimated using the computer program Surfer® which is distributed by Golden Software. As seen from Figure 3, the regional groundwater flow generally appeared to be in a northerly direction with a more northwesterly component on the east side of the site on January 29, 2002. As seen from Figure 3a, the local groundwater flow direction appeared to be to the east in the vicinity of the spill area with a southeasterly component east of the spill area on January 29, 2002. The hydraulic gradient was estimated to range from approximately 0.004 to 0.02 for the overall site while the hydraulic gradient was estimated to range from