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polyethylene (HDPE) liner. Additionally, six horizontal SVE wells were installed beneath five
<br /> apartment buildings in the Delta View Apartment complex. Analytical results of soil samples
<br /> collected at the bottom of the excavations indicated maximum concentrations of TPHd, TPHo,
<br /> TPHg, benzene, Methyl tertiary Butyl Ether (MtBE), and Tertiary Butyl Ether (TBA) of 12,000
<br /> milligrams per kilogram (mg/kg) (EX-3-B-J-10'), 2,200 mg/kg (EX-2-B-D-10' and EX-3-B-D-10'),
<br /> 5,400 mg/kg (EX-2-B-B-10'), 0.60 mg/kg (EX-3-B-J-10'), 0.0056 mg/kg (EX-3-B-G-10'), and 0.87
<br /> mg/kg (PLG-3-C-10'), respectively. Soil samples collected from the sidewalls of the excavations
<br /> contained TPHd, TPHo, TPHg, benzene, and TBA at maximum concentrations of 25,000 mg/kg
<br /> (EX-2-W-A-5'), 1,700 mg/kg (EX-3-W-A-5' and EX-3-W-A-8'), 2,400 mg/kg (EX-4-NE-8'), 0.060
<br /> mg/kg (EX-3-W-A-5'), and 0.82 mg/kg (EX-1-W-B-5'), respectively. MtBE was not detected at
<br /> or above laboratory method reporting limits (MRLs) in the sidewall samples. Interim results of
<br /> the investigation are presented in SECOR's Interim Pipeline Removal and Abandonment and
<br /> Soil Excavation Report, dated December 22, 2004. Final results and a work plan for additional
<br /> pipeline removal in the Waterfront Towers parking lot are presented in SECOR's Pipeline
<br /> Removal, Abandonment, Soil Excavation, On-Site Horizontal SVE Well Installation, and
<br /> Horizontal SVE Well Installation Beneath Delta View Apartments Report and Work Plan for
<br /> Pipeline Removal, Abandonment, and Soil Excavation in Waterfront Towers Parking Lot dated
<br /> February 10, 2005.
<br /> Additional assessment activities were conducted at the Site in May 2004 to investigate the
<br /> vertical extent of petroleum hydrocarbons in the vicinity of the Site. SECOR advanced one
<br /> deep soil boring (SB-7) to a depth of approximately 140 feet bgs in the vicinity of well MW-17,
<br /> installed shallow off-site well MW-45, and installed deep off-site wells MW-40 through MW-44
<br /> and MW-46. Three groundwater samples were collected at 117, 128, and 139 feet bgs using a
<br /> HydropunchTM sampling device in soil boring SB-7. Laboratory analysis of groundwater from
<br /> SB-7 indicated maximum concentrations of TPHd, TPHo, TPHg, benzene, MtBE, and TBA of
<br /> 8,300 micrograms per liter (ug/L; 139 feet bgs), 3,200 ug/L (139 feet bgs), 1,800 ug/L (117 feet
<br /> bgs), 200 ug/L (117 feet bgs), 4.5 ug/L (117 feet bgs), and 100 ug/L (117 and 128 feet bgs),
<br /> respectively. Two deep zone wells, MW-40 and MW-43, contained measurable SPH. Results
<br /> are summarized in SECOR's report entitled Additional Assessment Report and Work Plan for
<br /> Additional Deep Groundwater Zone Assessment dated July 29, 2004.
<br /> The initial start up of the DPE system was performed on August 2 and 3, 2004. Due to
<br /> concerns associated with operating the DPE system during the removal of former pipelines
<br /> found near the remediation system compound, the DPE system was temporarily deactivated on
<br /> August 3, 2004. The remediation system conveyance lines and nearby sewer and water lines
<br /> were also dismantled to accommodate the excavation of the abandoned former pipelines and
<br /> surrounding petroleum hydrocarbon-impacted soil. The DPE system was reconnected, brought
<br /> on-line on December 14, 2004, and operated during the first and second quarters of 2005.
<br /> Further discussion of the DPE system is included in Section 14.1.
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