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Based on field observations and the former equipment located in the building where the
<br />pipelines ran, the USTs are believed to have contained Bunker C fuel for boilers that
<br />were previously housed in the adjacent building.
<br />2.0 SUMMARY OF SOIL SAMPLE RESULTS
<br />2.1 Soil Sample Results
<br />Copies of the analytical results have been sent directly from McCampbell Analytical to
<br />the County as requested. Soil samples were analyzed for Total Petroleum
<br />Hydrocarbons in the gasoline range (TPHg), TPH in the diesel range (TPHd), Volatile
<br />Organic Compounds (VOCs) including BTEX, CL HC, Oxygenates (MTBE, TBA, DIPE,
<br />ETBE, TAME), 1,2 DCA, and EDB, PCBs, Luft Metals (Cd, Cr, Pb, Ni, and Zn), and
<br />hexavalent chromium (Cr VI).
<br />The analytical results received to date are presented in Table 1.0.
<br />A summary of the results from the four confirmation samples collected from the bottom
<br />of the excavation is provided below:
<br />• No PCBs were detected above the laboratory reporting limit.
<br />• The results for VOCs (EPA Method 8260) were all non-detected. The VOCs
<br />analyses included BTEX, CL HC, Oxygenates (MTBE, TBA, DIPE, ETBE,
<br />TAME), 1,2 DCA, and EDB.
<br />• The cadmium, chromium III, Cr VI, lead, nickel, and zinc results were significantly
<br />below the Regional Screening Levels (RSL) for industrial sites.
<br />• The results for TPHg were all non-detected (<1.0 mg/kg).
<br />• The TPHd results were non -detect (<1.0 mg/kg) in the southeast and southwest
<br />corners of the excavation (Tank 1 east and west end) and 110 mg/kg and 76
<br />mg/kg, respectively in the northeast and northwest (Tank 2 east and west end).
<br />Likewise the results from the northern trench samples (samples 001, 002, 003)
<br />collected on December 13, 2011 indicated no detection of PCBs, VOCs, or TPHg above
<br />the laboratory reporting levels. Cd, Cr III, Cr VI, Pb, Ni, and Zn levels were significantly
<br />below RSLs. The TPHd result for the easternmost sample (001) was 240 mg/kg and
<br />dropped as the samples moved away (west) from the excavation with the middle trench
<br />sample (002) at 190 mg/kg, and the westernmost trench sample (003) at non -detect
<br />(<1.0 mg/kg).
<br />Similarly, the results of the soil samples collected on December 13, 2011 from the soil
<br />stockpiles were non -detect for PCBs, VOCs, and TPHg as well as significantly below
<br />RSLs for Cd, Cr III, Cr VI, Pb, Ni, and Zn. The TPHd results ranged from 1.9 to 46
<br />mg/kg.
<br />The results from the southern trench samples collected on December 15, 2011
<br />indicated no detection of PCBs, VOCs, or TPHg above the laboratory reporting levels.
<br />Cd, Cr III, Cr VI, Pb, Ni, and Zn levels were significantly below RSLs. The TPHd results
<br />CE Project No. 11 R-120
<br />Work Plan — Cal Water Stockton 2
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