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4..v
<br /> 2002 CPT Borings: During June 2002, Cambria advanced seven CPT borings (CPT-5
<br /> through CPT-11). Soil samples were collected from CPT-5 only, and they provide
<br /> vertical definition of TPHg, benzene, and methyl tertiary butyl ether (MTBE) near the
<br /> current USTs. Depth-discrete groundwater samples were collected from all the borings.
<br /> Groundwater analytical data collected from borings CPT-6 through CPT-8 define the
<br /> lateral extent of petroleum hydrocarbons to the west,southwest, and south of the source
<br /> area. Groundwater samples from the CPT-9 through CPT-11 contained primarily TPHg
<br /> and benzene and to a lesser extent, MTBE. The highest concentrations of gasoline
<br /> constituents were detected at depths ranging from 65 to 73 fbg. The highest TPHg and
<br /> benzene concentrations were detected east of the former USTs in boring CPT-11 at
<br /> 65 fbg. Cambria's January 21,2003 Site Investigation Report describes this investigation.
<br /> 2004 Sensitive Receptor Survey: CRA conducted a sensitive receptor survey (SRS) in
<br /> 2004 to identify surface water bodies and sensitive habitats within 500 ft; basements
<br /> within 200 ft; hospitals, educational, residential care and child care facilities within 100
<br /> ft.; and water wells within one-half mile of the site. The survey was confirmed by a field
<br /> visit. No surface water bodies or active water producing wells were identified within
<br /> 2,000 feet of the site. Based on the SRS,there are no sensitive receptors to protect.
<br /> 2004 Site Conceptual Model: On October 7, 2004,Cambria submitted a Site Conceptual
<br /> Model (SCM) which summarized previous activities and recommended additional CPT
<br /> borings.
<br /> 2005 Subsurface Investigation: During October 2005, Cambria advanced six soil borings
<br /> (CPT-12 through CPT-17). Borings CPT-12, CPT-13, and CPT-17 were advanced to a
<br /> depth of 100 fbg. Borings CPT-14, CPT-15, and CPT-16 were advanced to 40 fbg. No
<br /> TPHg, benzene, fuel oxygenates, 1,2-dichloroethane (1,2-DCA), or ethylene dibromide
<br /> (EDB) were detected in any soil sample collected during this investigation.
<br /> Groundwater samples were collected from borings CPT-12 (at depths of 47, 56, 66, 74,
<br /> 79, and 87 fbg), CPT-13 (at 53,60, 77, and 87 fbg), CPT-14 (at 28 fbg), CPT-16 (at 25 and /
<br /> 32 fbg),and CPT-17(at 41, 67, 75,83, and 90 fbg). '
<br /> The highest concentration of gasoline constituents were detected at depths of 32 fbg.
<br /> �i
<br /> The highest TPHg and benzene concentrations were detected northwest of the former
<br /> USTs in boring CPT-16 at 32 fbg. Cambria's April 6, 2006 Subsurface Investigation
<br /> Report describes this investigation. I(-
<br /> 2007
<br /> .2007 Subsurface Investigation: During July 2007, Cambria installed four groundwater
<br /> monitoring wells (MW-16-50, MW-16-77, MW-16-90, and MW-17-50). Groundwater
<br /> samples from the newly installed wells contained up to 34,000µg/L TPHg, 1,200µg/L
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