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!C the existing ice manufacturing building. ,Confirmation samples collected.from the sidewalls and floor of the excavation indicate no detectable BTEX and up to 138 mg/kg of TPH as kerosene (TPH-k) in the north and west sidewalls at a depth of approximately 20 feet bgs. Groundwater monitoring at the siteAndicate that the wells in the vicinity of Tank #4, MW-5 and MW-3, have:not had detectable BTEX concentrations and have had TPH-d concentrations up to 0.4 mg/L. The wells in the vicinity of Tank #3,'MW-1 and MW-2, have had TPH-g detected at up.to 1.3 mg/L, TPH-d up to 0.2 mg/L, benzene u to 50 toluene u to 9 eth. lbenzene u to 40 and xylenes u to P uP� p >sl�-, Y p uP� xY P 63 4g/L. The water level in Well MW-4 indicates that this well may be downgradient of both the Tank #3 and the Tank #1 and #2 vicinities (Figure 2). However, MW-4 was not surveyed at the same time as the other wells, and the other wells were not resurveyed i when this well was surveyed. For this reason the groundwater gradient data obtained from this well has only been used qualitatively; and it is proposed that. a level survey_ be_ - conducted to establish an accurate top-of-casing reference elevation for MW-4 (see Section 3). 3.0 PURPOSE The objectives of this investigation are 1) to identify the source(s) of aromatic hydrocarbons impacting groundwater at the site; 2) to.evaluate the lateral and vertical extent of hydrocarbons in the vadose zone to allow for the preliminary design of a soil treatment system, if further remediation is deemed necessary, and 3) to gain information - - i t The first sample collected from MW-5 in October, 1994 indicated benzene present at the detection limit of 5 ug/L; however, benzene was not detected in the duplicate sample from the same 'monitoring event (less than i ug/L) nor in any subsequent samples (less than 0.5ug/L). The single detection is therefore suspected to be a laboratory artifact. R4182OA-1222950-3 soilvap.pin 3