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Appendix C: Previous Environmental Activities
<br /> RADIAN INTERNATIONAL,LLC (RADIAN) 1997 GROUNDWATER
<br /> INVESTIGATIONS
<br /> On February 27, 1997, Radian was contracted by CPL to conduct a limited groundwater
<br /> investigation at the Hunter Container property to determine if TCE had affected the groundwater.
<br /> Radian advanced three cone penetration test(CPT)borings(CPT-1, CPT-2, and CPT-3), and
<br /> groundwater samples were collected at 35 and 50 feet bgs and tested by an analytical laboratory.
<br /> TCE was not detected in any sample. Cis-1,2-dichloroethene, a degradation product of TCE,
<br /> was detected in one of the groundwater samples at a concentration below the United States
<br /> Environmental Protection Agency(EPA)Maximum Contaminant Level (MCL) for drinking
<br /> water. Radian concluded that"TCE and other chlorinated organic hydrocarbons have not
<br /> impacted groundwater."
<br /> RADIAN 1998 SITE INVESTIGATION'
<br /> In July 1998, six soil borings (B-1 through B-6)were advanced at Hunter Container and three
<br /> monitoring wells (MW-2, MW-3, and MW-4)were installed. TPHg, TPHd, and TPHmo were
<br /> detected in borings B-1, B-4, B-5, B-6, and monitoring well MW-2. Elevated concentrations of
<br /> TPHg (1,400 mg/kg) were detected in B-5 at 10 feet bgs, and TPHd(21,000 mg/kg) and TPHmo
<br /> (15,000 mg/kg)were also detected in B-5 at 20 feet bgs. Laboratory analytical results indicated
<br /> TPHd concentrations of 2,300 and 300 gg/L in wells MW-2 and MW-3, respectively; and a
<br /> TPHmo concentration of 700 gg/L in MW-2. No other constituents of potential concern
<br /> (COPCs)were detected in groundwater samples.
<br /> GEOMATRIX CONSULTANTS,INC. (GEOMATRIX)2000 SOIL AND
<br /> GROUNDWATER INVESTIGATION
<br /> On November 9 through 11, 1999, at the request of Chevron Environmental Management
<br /> Company(CEMC), Geomatrix advanced seven soil borings (GMX-1 through GMX-7)to assess
<br /> the vertical and lateral extent of affected soil and groundwater. Borings GMX-6 and GMX-7
<br /> were advanced off site, on the east side of Highway 33. Additionally, groundwater samples were
<br /> collected from monitoring well WFSMW-1 on the Western Farm Service (now Crop Production
<br /> Services [CPS])property and tested for the COPCs. The investigation also evaluated the
<br /> presence of TCE in site soil at the request of the Central Valley Regional Water Quality Control
<br /> Board(RWQCB).
<br /> TPH quantified as crude oil(TPHc)were detected in soil at a concentration of 10,000 mg/kg at
<br /> 37 feet bgs from GMX-3, and polynuclear aromatic hydrocarbons (PAHs) were detected at
<br /> concentrations ranging from 0.007 to 0.55 mg/kg.
<br /> TPHd, TPHg, PAHs, and BTEX were not detected in the groundwater sample collected from
<br /> WFSMW-1. TPHg and TPHd were detected in the groundwater sample from GMX-6 at
<br /> concentrations of 110 and 92 µg/L,respectively.
<br /> Geomatrix concluded that TPHd in down-gradient groundwater samples was either at non-detect
<br /> concentrations or below Central Valley RWQCB Water Quality Objectives (WQOs)8. TCE was
<br /> 5. Radian, 1997. 27 February 1997 Groundwater Sampling at 35275 Welty Road, Vernalis,California. March.
<br /> 6. Radian, 1998. Site Investigation.
<br /> 7. Geomatrix,2000. Soil and Groundwater Investigation Report,35275 Welty Road,APN 255-180-09, Vernalis, California.
<br /> February.
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