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�e Page 3 Mr Michael lnfurna Jr,Senior REHS May 15,2003 EHD requested that additional investigation be performed to assess the extent of petroleum impact PESC submitted a September 24, 2001 Subsurface Site Investigation Workplan to EHD, which proposed further assessment EHD approved this work plan in a letter dated October 16, 2001 PESC performed the latest investigation in March of 2002 PESC drove 6 Geoprobe borings (PH-3 through PH-8), installed one groundwater monitoring well (MW-4), constructed one air spargmg well (SP-1), one soil vapor extraction well (VW-1), and collected soil and groundwater samples for laboratory analysis Investigation findings, submitted to EHD in the May 14, 2002 March 2002 Subsurface Site Investigation report, included the following • Subsurface soils in the vicinity of the Site are primarily comprised of silt and clay to at least 50 feet • Initial groundwater, situated in the clayey matrix, was typically observed at a depth of 30 to 35 feet Groundwater is slow to yield, but typically rises under confined pressure to about 23 to 25 feet • Groundwater flows easterly at a gradient of about 0 0026 ft/ft © BTEX concentrations in soil samples collected above the groundwater table are relatively low compared to those obtained below Higher BTEX concentrations in soil samples collected below the groundwater table may be a result of the contaminated groundwater present within their matrix TPHg concentrations in soil samples collected above the groundwater table are relatively higher compared to those obtained below BTEX concentrations, once potentially present in these higher TPHg-impacted soil samples, appear to have degraded �) • The lateral extent of petroleum impacted soil appears to be narrowly confined in the vicinity of the former UST The vertical extent of impact is evaluated to be 50 to 55 feet • Oxygenate compounds have not been detected in any soil sample • BTEX and TPHg concentrations in groundwater at the MW-2 location are relatively high • BTEX and TPHg concentrations in groundwater at the MW-1,MW-3, MW-4 and PH-8 locations are relatively low or were not detected • BTEX and TPHg concentrations in groundwater at the PH-6 and PH-7 locations may be a result of previous retail gasoline operations at the 1725 El Dorado Street property