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• 'i v Ms. Lori Duncan Page 5 of 6 • Drilling refusal was encountered in all borings at depths ranging from 16.5 to 17 feet bgs. A result of the hardpan formation. • The lateral and vertical extent of soil contamination has been defined. 6.0 CONCLUSIONS AND RECOMMENDATIONS 6.1 Conclusions Although it is evident that the site has been impacted, only one sample collected from boring SB 1, located within the former tank excavation, gave evidence of petroleum hydrocarbon contamination. The only hydrocarbon analyte present in significant concentrations was oil and grease. The confining properties of the hardpan formation appear to have prevented vertical migration of contaminants. It is not expected that contaminants have migrated to groundwater. The data from this investigation combined with data previously obtained have defined the extent of soil contamination. Residual soil contamination of any significance appears to be present only within the former UST excavation. 6.2 Recommendations Based upon the localized contamination and its(current) accessibility Ground Zero recommends the implementation of interim remedial actions consisting of soil excavation and disposal. We do not recommend additional drilling at this time. 7.0 WORKPLAN FOR INTERIM REMEDIATION We propose using an excavator to remove residual soil contamination from the approximate area depicted on Figure 3. Excavation will continue laterally within the boundary defined by the former perimeter borings(SB2-SB4)or until field evidence indicates that the majority of contaminated soil has been removed(the lateral limit of excavation will be limited on the east due to the site building). Excavation will proceed vertically until field evidence indicates that the majority of contaminated soil has been removed, an estimated depth of approximately 17 feet. It is estimated that 180 cubic yards of soil, or less, will be excavated. Following the completion of excavation, confirmation soil samples will be collected from the floor of the excavation. An effort will be made to collect one soil sample from a depth of 20 feet or more to provide further assurance that the vertical limit of contamination has been defined. Confirmation samples will also be collected from any sidewall of the excavation that has not been excavated to a previous non-detect soil boring, such as the east wall. The soil samples will be analyzed by a state- certified laboratory for TPHg, BTEX, TOG and VOC's using appropriate analytical methods. The excavated soil will be stockpiled on a paved surface and covered with plastic pending disposal. One four-tube composite soil sample will be collected from each 50 cubic yards of excavated soil NsautolreportslsummaryWP.doc