ARCHIVED REPORTS_SEPARATE PHASE HYDROCARBON INVESTIGATION UNOCAL EXTRACTION WELL PILOT STUDY 2011

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Stantec Report of Findings for the Waterfront Towers Separate Phase Hydrocarbon Investigation and Unocal Extraction Well Pilot Study Waterfront Towers Parking Lot March 4, 2011 In 2001, additional assessment activities were conducted by T&R in the vicinity of the Site within Parcel 3. Results are included in T&R's report entitled Subsurface Investigation for Area 3, dated August 17, 2001. In September 2001, 11 Cone Penetrometer Test (CPT) borings (DP-1 through DP-11) were advanced to investigate the following: (1) subsurface lithology; (2) the presence SPH; (3) the lateral extent of petroleum hydrocarbon-impacted groundwater east, south, and west of the Site; and (4) to investigate potential offsite sources upgradient (north-northwest) of the Site. Surficial soil samples were also collected from depths up to five feet below ground surface (bgs) to evaluate whether the presence of residual concentrations of metals present a threat to groundwater quality. Results are presented in the Clayton Group Associates (Clayton) Further Characterization at the West Weber Avenue and North Lincoln Street Site, Parcel 2A, dated December 18, 2001. In May 2002, Clayton initiated quarterly monitoring activities, installed eight additional CPT soil borings (DP-12 through DP-19), and collected grab samples to delineate soil and groundwater impacts previously identified in the vicinity of borings DP-1 through DP-6. In addition, Clayton performed a soil gas survey in July 2002 involving the installation of 111 Gore-Sorber® modules to investigate the areas of greater petroleum hydrocarbon impact. Results are summarized in Clayton's Site Delineation Report, dated August 6, 2002. In December 2002, a five-day dual phase extraction (DPE) feasibility test was performed by SECOR, following the installation of seven DPE wells (DPE-1 though DPE-7). SPH was reportedly present in wells DPE-1, DPE-3, DPE-4, DPE-6, and DPE-7 prior to testing. DPE tests were performed utilizing well 2AMW-14 for approximately 45 hours; simultaneously on wells DPE-4 and DPE-6 for approximately 28 hours; and simultaneously on wells DPE-1, DPE- 3, and DPE-7 for approximately 26 hours. Results of DPE feasibility testing indicated the following: (1) a calculated radius of influence of 31 feet west of well 2AMW-14, and lower estimated radii of influence to the south and east due to the presence of low permeability clays and lower induced vacuum readings in wells DPE-3, DPE-4, and DPE-7; and (2) the removal of an estimated 196.38 pounds (Ibs) of total petroleum hydrocarbons in gasoline range organics (TPHg) from soil and groundwater, 97.02 lbs of total petroleum hydrocarbons in diesel range organics (TPHd) from groundwater, and 9.57 lbs of total petroleum hydrocarbons in motor oil range organics (TPHo) from groundwater. Results are summarized in SECOR's Well Installation and DPE Feasibility Report, dated January 24, 2003. An additional DPE test was performed at the Site between March 3 through 7, 2003, using a 25-horsepower (hp) liquid ring vacuum pump connected to a thermal oxidizer unit for abatement of the extracted soil vapor prior to discharge into the atmosphere. DPE tests were performed separately on wells DPE-4 and 2AMW-14 simultaneously for approximately 21.5 hours and (e wells DPE-4, DPE-6, and 2AMW-14 simultaneously for approximately 72.5 hours. The DPE unit ran for approximately 97 hours during the test. Groundwater and soil vapor were removed 2.4