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�1 Rpm) in 32 of the 37 sod samples The ubiquitous trace concentrations of toluene may be an artifact of paint blending operations by the prior property operator Neither TPH-as-gasoline nor benzene, ethylbenzene or xylenes were detected in any of the sod samples The results of the soil sample analyses are summarized in Table 1 Groundwater was encountered in EX-1 and BH-4 at a depth of approximately 42 feet bgs Groundwater grab samples collected for laboratory analysis from these two borings did not contain detectable concentrations of TPH-as-gasoline or BTEX compounds Total lead was detected in groundwater from EX-1 at a concentration of 1,000 micrograms per liter (µg/L) and from BH-4 at 80 µg/l_ The results of the groundwater grab sample analyses are summarized in Table 2 On April 4, 1990, AEMC over-excavated the eastern end of the former Tank A excavation to a total depth of 25 feet bgs Confirmation sod sample results were deemed invalid by PHS/EHD due to improper sample collection and preservation techniques Approximately 78 cubic yards of excavated soil was spread on-site for aeration Disposition of the excavated soil is not documented in the regulatory files In May 1996, no soil stockpile was present at the site On July 2, 1990, AEMC installed three groundwater monitoring wells (MW-1, MW-2 and MW-3) and one soil boring (SB-1) to further evaluate soil and groundwater conditions (Figure 2) The construction of the monitoring wells is summarized in Table 3 Soil boring SB-1 was positioned at the east end of the former Tank A excavation to penetrate the excavation backfill and re- sample native soil at the bottom depth of the former excavation This soil sampling was necessary to replace the invalid confirmation sample results Soil samples collected for analysis from SB-1 revealed TPH-as-gasoline at a concentration of 12 ppm at 29 feet bgs and 4 4 ppm at 29 5 feet bgs Sixteen soil samples collected for analysis during the drilling of MW-1, MW-2 and MW-3 revealed only trace concentrations of toluene (up to 0 077 ppm) The results of the soil sample analyses are summarized in Table 1 Initial groundwater sampling data from the newly- installed monitoring wells are not included in the regulatory documentation From May 1996 to June 1997, IT Corporation monitored and sampled the three groundwater L monitoring wells for five consecutive quarters Groundwater was found at depths ranging from approximately 31 to 38 feet bgs During the entire monitoring and sampling period, the groundwater elevation in each of the wells was found to be above the top of the well screens Groundwater flows primarily to the east at a gradient of approximately 0 002 ft/ft (Figure 3) The groundwater monitoring data is summarized in Table 4 3