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APPENDIX B: <br /> PREVIOUS ENVIRONMENTAL ACTIVITIES <br /> CONDOR EARTH TECHNOLOGY (CONDOR) 2001 CHEVRON PIPELINE <br /> EASEMENT ASSESSMENT REPORT <br /> Condor's 2001 pipeline easement assessment report documented affected soil at the site in <br /> borings GP 152, GP 156 through GP 158, GP 160, and GP 161 at depths ranging from 4.5 to 20 feet <br /> below ground surface (bgs). Soil samples were collected at boring locations and submitted to a <br /> laboratory for analytical testing. Laboratory analytical results indicated detectable total <br /> petroleum hydrocarbons quantified as crude oil (TPHc) at concentrations ranging from <br /> 880 milligrams per kilogram(mg/kg) in GP 152 at 15.5 feet bgs to 29,000 mg/kg in GP 156 at <br /> 12 feet bgs. <br /> Grab groundwater samples were also collected at boring locations and submitted to a laboratory <br /> for analytical testing. TPH quantified as diesel (TPHd) were detected at concentrations ranging <br /> from 2,200 micrograms per liter(gg/L) in GP-152 to 260,000 gg/L in GP161. TPH quantified as <br /> gasoline (TPHg) were also detected at concentrations ranging from 8,500 gg/L in GP156 to <br /> 9,900 gg/L in GP 161. <br /> Soils encountered in the borings were predominantly clays, silts, and sands. Borings advanced <br /> on the shoulder of Byron Road encountered clay and gravel fill in the upper 1 to 3 feet that <br /> appeared to be road sub-base. Groundwater was observed at the site at depths ranging from 7 to <br /> 17 feet bgs. <br /> SAIC 2008 SOIL AND GROUNDWATER INVESTIGATION REPORT <br /> From March 17 through April 1, 2008, SAIC advanced 29 borings (SB-I through SB-29)using a <br /> Geoprobe® 6600 direct-push rig. Borings were advanced to total depths between 12 and 40 feet <br /> bgs. Hydrocarbon-affected soil was encountered in SB-1, SB-2, SB-5, SB-8 through SB-16, <br /> SB-18, and SB-21 through SB-23. <br /> TPHc were detected above Environmental Screening Levels (ESLs) in I I soil borings. The <br /> highest concentration was detected in boring SB-21 at 6 feet bgs (29,000 mg/kg). Benzene, <br /> toluene, ethylbenzene, and total xylenes (BTEX)were detected above ESLs or Regional <br /> Screening Levels (RSLs) in two soil borings with a maximum concentration(ethylbenzene at <br /> 0.14 mg/kg) detected in SB-10 at 18 feet bgs. Polynuclear aromatic hydrocarbons (PAHs)were <br /> detected in soil samples from 15 borings with a maximum concentration(chrysene at 1.6 mg/kg) <br /> detected in SB-21 at 5 feet bgs. Three samples (SB-5 at 14 feet bgs, SB-10 at 17 feet bgs, and <br /> SB-14 at 23 feet bgs)were submitted to Chevron Energy Technology Company(ETC) for fuel- <br /> fingerprint analyses. ETC concluded that the three samples contained moderately weathered San <br /> Joaquin Valley crude oil. <br /> Groundwater samples were collected from 20 borings. TPHd were detected above ESLs in <br /> groundwater samples from three borings. The highest concentration (benzo[a]pyrene at <br /> 0.004 gg/L) was from a sample collected from SB-15 at 30 feet bgs. BTEX constituents were <br /> not detected above ESLs or Water Quality Objectives (WQOs) in any samples. PAHs were <br /> detected in groundwater samples from three borings with a maximum concentration <br /> 1. Condor,2001. Chevron Pipeline Easement Assessment Report—Mountain House, California, Volume 1&2.November. <br /> 2. SAIC,2008. Soil and Groundwater Investigation Report—Mountain House Development Site#6. July. <br /> B-1 ZZ <br /> = <br /> r�rs�`m <br /> Fran;Science to solutions <br />