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Stantec
<br /> Site History and Previous Investigations
<br /> Stockton Charter Way Commingled Plume No. CP0057
<br /> November 15, 2011
<br /> one 1,000-gallon waste oil UST, associated dispenser islands and product lines, one dual-post
<br /> hydraulic hoist with tank, two semi-hydraulic hoists, and one sump from the property. The
<br /> 10,000-gallon USTs contained supreme unleaded and regular unleaded gasoline. The 6,000-
<br /> gallon UST contained unleaded plus gasoline. Over-excavation was performed in the former
<br /> UST complex, former product dispenser islands area, and the dual-post hydraulic hoist area.
<br /> The over-excavated areas were sampled and enlarged based upon the analytical sample
<br /> results. Approximately 52 soil samples (T1 through T6, TXS1 through TXS6, TXB1
<br /> through TXB3, UO, UOB, P1 through P7, PXS1 through PSX3, PXB1 through PXB7,
<br /> OX1, OX2, OXS1 through OXS3, OXB1 through OXB4, RF, RF2, H1 through H4,
<br /> HT, HX, and SUMP) were collected during these activities. TPHg, benzene, MTBE,
<br /> and total oil and grease were detected in soil samples collected during the removal and
<br /> excavation activities at concentrations up to 3,000, 14, 28, 14,000 mg/kg, respectively. These
<br /> activities are summarized in the Touchstone UST Closure Report and Limited Over-excavation
<br /> Sampling Report dated August 7, 1997.
<br /> Former Colombo/Toscana Bakery (Sara Lee)
<br /> Colombo/Toscana owned and operated two 4,000-gallon gasoline UST systems for fleet
<br /> refueling at the property. The USTs were located west of and adjacent to the warehouse
<br /> building. The fuel dispenser was located inside the building near the northwestern corner.
<br /> Environmental investigations have been performed at the property since February 1996 to
<br /> evaluate the degree and extent of contamination in soil and groundwater. Mr. Edward Overton
<br /> currently owns the property.
<br /> In February 1996, SECOR advanced four soil borings (MW-1, VE-1, SB-1, and SB-2). A
<br /> groundwater monitoring well was installed in MW-1 and a vapor extraction well was installed
<br /> in VE-1. TPHg and benzene were detected in soil samples collected during the installation
<br /> activities at concentrations up to 13,000 and 44 mg/kg, respectively. TPHg and benzene were
<br /> detected in groundwater samples collected from these borings at concentrations up to 190,000
<br /> and 22,000 pg/L, respectively. These activities are summarized in the SECOR Summary Report,
<br /> Site Investigation dated June 11, 1996.
<br /> In October 1997, SECOR advanced one soil boring (MW-7) through the former UST excavation. A
<br /> dual-nested groundwater monitoring well (MW-7S and MW-7D) was installed in MW-7. TPHg,
<br /> benzene, and MTBE were detected in soil samples collected during the installation activities at
<br /> concentrations up to 390, 2.3, and 0.052 mg/kg, respectively. TPHg, benzene, and MTBE were
<br /> detected in groundwater samples collected from this boring at concentrations up to 400,000,
<br /> 19,000, and 120 pg/L, respectively. These activities are summarized in the SECOR Results of
<br /> Deeper Exploratory Boring and Well Installation and Work Plan to Perform a Cone
<br /> Penetrometer Testing (CPT) Survey dated November 24, 1997.
<br /> In December 1997, SECOR advanced three CPT borings (CPT-1 through CPT-3) to further
<br /> assess the vertical and horizontal extent of petroleum hydrocarbons beneath the property.
<br /> TPHg was detected in groundwater samples collected from these borings at concentrations up
<br /> to 17,000 pg/L. These activities are summarized in the SECOR Results of Cone Penetrometer
<br /> Testing (CPT) Survey dated March 9, 1998.
<br /> Stockton Charter Way Site History and Previous Investigations.doc 5
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