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Page 3 Mr Michael Infurna Jr,Senior REHS September 24,2001 SUBSURFACE SITE CONDITIONS Descriptions of subsurface soil and groundwater conditions are contained in the following sections Subsurface Soil Conditions Subsurface soils in the vicinity of the site are comprised of interlayered clay, silt, sand and gravel PSC's interpretation of the soil stratigraphy and the depth to first groundwater differed somewhat from GZA's interpretation In probeholes PH-1 and PH-2, PSC observed clayey silts and silty clays to a depth of 50 feet, underlain by a confined sandy groundwater-bearing strata at 50 feet Groundwater was observed to rise under potentiometric pressure from 50 feet to about 25 feet In wells MW-1 and MW-3, GZA observed clayey intervals However, they also reported 12 to 15-feet thick sand and gravel layers at depths from about 19 to 34 feet GZA observed primarily fine-grained strata in MW-2 and only a relatively thin stringer of sand, at the 34-feet depth GZA reported that groundwater was encountered at a depth of 23 feet in MW-1 and MW-3, and at about 30 feet in MW-2 under unconfined conditions PSC and GZA collected a combined total of seventeen soil samples for laboratory analysis PSC's eleven samples from PH-1 and PH-2 were analyzed for BTEX, TPHg and gasoline oxygenate compounds GZA's six samples were analyzed for BTEX and TPHg As shown in Table 1, results from these analyses indicate the following Oxygenate compounds were not detected in any of PSC's soil samples, BTEX and TPHg concentrations were not detected in any of the GZA samples collected from MW-1 and MW-3, and, The vertical extent of significant petroleum impact at the former UST source appears to be about 50 feet below ground surface as indicated by the non- detectable petroleum concentrations measured in the 50-feet sample collected from PH-2 Toluene, ethylbenzene and xylenes compounds were detected in the 50-feet sample from PH-1, however, their respective concentrations were just slightly above the laboratory's detection limit r