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30 January 2014 AGE Project No . 99-0682 Page 9 of 28 / Hydrogeologic Unit 7 (HU7) - extends from 161 feet to 177 feet bsg ; the unit is characterized by a thick sand interval on the eastern edge of the site which appears to transition to interbedded stiff fine grained soil , clays and silts towards the west. Pore pressures in HU7 range between low pressures in the sand interval to moderately low to moderate in the finer-grained soils . Hydrogeologic Unit 8 (HU8) - extends from 177 feet to 190 feet bsg ; HU8 consists primarily Zof silt and clay; the unit is characterized by moderately low to moderate pore pressures . Hydrogeologic Unit 9 (HU9) - extends from 190 feet to 195 feet bsg ; the unit is a silty sand to sandy silt layer characterized by low and some moderate pore pressures. Hydrogeologic Unit 10 (HU10 ) - extends from 195 feet to 200 feet bsg ; HU10 is j ' redominately silt and clay; the unit is characterized by moderate and some low pore pressures . Bering and CPT logs are included in Appendix B . Cross Sections showing general site thology are included in Figures 3 and 4. 5.0 . PETROLEUM HYDROCARBON DISTRIBUTION IN SOIL Based on soil samples collected to date , the site appears to be primarily impacted by TPH-g , TPH-d , and BTEX constituents . Constituents of concern appear to be located around the tank pit area and radiate to the north towards MW- 11 and to the east near MW-7 . A large portion of the adsorbed hydrocarbon plume has been remediated by soil vapor extraction performed at the site between September 2010 and October 2011 . The majority of the remaining hydrocarbon-impacted soil is below the current water table level located at approximately 25 feet bsg . For modeling and mass calculation purposes the adsorbed hydrocarbon plume has been differentiated into three depth zones : 10 to 25 feet bsg (Figure 5) , 25 to 60 feet bsg (Figure 6 ) and 60 to 100 feet bsg (Figure 7) . Utilizing VW-2 (UST area) as amid-point, the lateral extent of TPH-impacted soil in the 10 to 25 foot zone appears to extend approximately 18 feet to the north , 12 feet to the south, 19 feet to the east and 21 feet to the west (Figure 5). Utilizing VW-2 (UST area) as a mid-point, the lateral extent of TPH-impacted soil in the 25 to 60 foot zone appears to extend approximately 34 feet to the north , 40 feet to the northeast, 13 feet to the south , 23 feet to the east and 28 feet to the west ( Figure 6) . Advanced GeoEnvironmental, Inc,