|
' Appendix B:Previous Environmental Activities
<br /> RADIAN INTERNATIONAL, LLC (RADIAN)
<br /> 1997 GROUNDWATER INVESTIGATIONS
<br /> On February 27, 1997, Radian was contracted by CPL to conduct a limited groundwater
<br /> investigation at the Hunter Container site to determine if TCE had affected groundwater. Three
<br /> cone penetration test(CPT) borings (CPT-1, CPT-2, and CPT-3) were advanced by Radian, 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 U.S. Environmental
<br /> Protection Agency (EPA)Maximum Contaminant Level (MCL) for drinking water. Radian
<br /> concluded that "TCE and other chlorinated organic hydrocarbons ha[d] not impacted
<br /> groundwater."
<br /> ' RADIAN 1998 SITE INVESTIGATION
<br /> On July 15, 22, and 23, 1998, six soil borings (B-1 through B-6) were advanced at the Hunter
<br /> Container site and three monitoring wells (MW-2, MW-3, and MW-4) were installed. TPHg,
<br /> TPHd, and TPHmo were detected in borings B-1, B-4, B-5, B-6, and monitoring well MW-2.
<br /> High concentrations of TPHg (1,400 mg/kg) were detected in B-5 at 10 feet bgs, and TPHd
<br /> (21,000 mg/kg) and TPHmo (15,000 mg/kg) were also detected in B-5 at 20 feet bgs.
<br /> Laboratory analytical results indicated TPHd concentrations of 2,300 and 300 btg/L in wells
<br /> MW-2 and MW-3, respectively; and a TPHmo concentration of 700 µg/L in MW-2. No other
<br /> constituents of potential concern (COPCs) were detected in groundwater samples.
<br /> GEOMATRIX CONSULTANTS, INC. (GEOMATRIX)
<br /> 2000 SOIL AND 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 GMW-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 CPS property and tested for the COPCs. The
<br /> investigation also evaluated the presence of TCE in site soil at the request of the 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 non-detect or
<br /> below RWQCB Water Quality Objectives (WQOs). The presence of TPHg, benzene, and
<br /> naphthalene in GMX-6 was likely from the adjacent former gasoline station, and not from the
<br /> former Old Valley Pipeline (OVP) or Tidewater Associated Oil Company (TAOC) pipelines.
<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.
<br /> 1 B-3 =m =a
<br /> Wo:::
<br /> �rs�a..®
<br /> From Science to Solutions
<br />
|