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aquifer The base of the A zone is at approximately 17 - 18 feet below ground surface (bgs) An aquitard consisting of silty clay approximately 3 to 4 feet thick separates the silty clayey sand A zone aquifer from the B zone aquifer that is found at approximately 21 feet bgs and is approximately 6 to 7 feet thick The aquitard separating the A and B zone aquifers is considered leaky, see section on pump test results and Appendix D - Pump Test The B zone aquifer consists of cleaner moderately sorted fine to coarse sand that shows graded bedding(fine to coarse with depth) Beneath the B zone aquifer is stiff clay that extends from approximately 27 feet bgs to 40 feet bgs The original five monitor wells did not encounter groundwater in the A zone aquifer when initially drilled and sampled Depth to water measurements taken between 1993 and February 1996 indicate that the A zone aquifer was dry (depth to water greater than 17 feet bgs) MW 1 through MW5 are screened across both the A and B zone aquifers Sometime after February 1996 depth to groundwater measurements indicated that groundwater was in contact with the A zone aquifer, see Table 1 and Figures 8 and 9 The groundwater in the vicinity of the site is semiconfined Groundwater elevation at the site vanes from a wet year high of 7 feet bgs (silty clay formation above the A zone) to about 22 - 23 feet bgs (B zone) during the previous drought period Groundwater flow direction in the A zone at the site has generally been to the west since December 1997 The B zone shows a similar flow direction, which would be expected due to the connection between zones at wells MW 1 through MW5 EXCAVATED CONTAMINATED SOILS STORAGE Prior to starting excavating contaminated soils an excavated soil storage area was prepared Utilizing the fenced back lot of the site an 1850 square foot bermed and plastic lined soil storage area was constructed In the southeast corner a fluid collection sump was installed The lined storage area sloped to the collection sump, which was placed on top of the plastic liner and within the 2-3 inch thick sand placed on top of the plastic liner to act as fluid delivery to the sump An estimated 750 cubic yards (accounting for an anticipated 20% fluff factor of the calculated excavated 639 yards) of gasoline contaminated soil was stockpiled within this soil storage area This soil was then covered with plastic liner to prevent the release of hydrocarbon vapors and to prevent fluid entry from recent storms Twelve soil samples were obtained from the stockpiled soil and submitted to Kiff Analytical Laboratory (DHS#2236), whom composited the samples into three for analysis as TPH gasoline, Benzene, Toluene, Ethylbenzene and Xylenes using EPA Method 8260B and analysis as total lead using EPA Method 6010B The results showed composite soil sample SP A-B-C-D contained 2000 mg/Kg TPHg, 0 53 mg/Kg Benzene, 12 mg/Kg Toluene, 8 1 mg/Kg Ethylbenzene, 120 mg/Kg Xylenes and 114 mg/Kg total Lead Sample SP E-F-G-J contained 280 mg/Kg TPHg, <0 05 mg/Kg Benzene, 0 32 mg/Kg Toluene, 0 16 mg/Kg Ethylbenzene, 15 mg/Kg Xylenes and 12 7 mg/Kg total Lead Sample SP H-I-K-L contained 2500 mg/Kg TPHg, <0 05 mg/Kg Benzene, 3 5 mg/Kg Toluene, 4 0 mg/Kg Ethylbenzene, 150 mg/Kg Xylenes and 16 3 mg/Kg total Lead The above results indicate that this soil can be hauled and disposed as non hazardous waste to a Class II designated landfill 5 SOIL REMOVAL APRIL 2003