|
Appendix A:Previous Environmental Activities
<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)9. TCE was
<br /> not detected in the soil samples analyzed. The presence of TPHg,benzene, and naphthalene in
<br /> GMX-6 was likely from the adjacent former Union Oil Service Station, and not from the former
<br /> Old Valley Pipeline(OVP)or Tidewater Associated Oil Company(TAOC)pipelines.
<br /> GEOMATRIX 2002 SOIL AND GROUNDWATER INVESTIGATION Io
<br /> On May 20 and 21, 2002, Geomatrix advanced three soil borings (GM-8, GMX-9, and
<br /> GMX-1B) at the site to further assess the extent of affected soil and groundwater. TPHc were
<br /> detected in soil from GM-8 at concentrations of 8,000 mg/kg at 5 feet bgs and 1,200 mg/kg at
<br /> 55 feet bgs, and at 5,100 mg/kg in GMX-1B at 30 feet bgs. Benzene was detected only in
<br /> GM-8 at a concentration of 0.067 mg/kg at 55 feet bgs. Toluene was detected in all samples at
<br /> concentrations ranging from 0.006 to 0.58 mg/kg. Ethylbenzene concentrations ranged to
<br /> 0.87 mg/kg in GM-8 at 55 feet bgs. Xylenes were reported up to 2.1 mg/kg in GMX-1B at
<br /> 30 feet bgs. Various PAHs were reported in the GMX-8 sample collected at 55 feet bgs, and in
<br /> the GMX-1B sample collected at 30 feet bgs.
<br /> GEOMATRIX 2003 OFF-SITE SOIL AND GROUNDWATER INVESTIGATION"
<br /> The Central Valley RWQCB requested additional off-site assessment, and Geomatrix
<br /> subsequently advanced three off-site soil borings (GMX-10, GMX-11, and GMX-12)between
<br /> the former HPP-BTR pipelines and Welty Road. A TPHc concentration of 15,000 mg/kg was
<br /> detected in the soil sample from GMX-12 collected at 41.5 feet bgs. Benzene,toluene, and total
<br /> xylenes were also detected in soil from GMX-12. TPHd concentrations were detected in
<br /> groundwater samples collected from GMX-10, GMX-11,and GMX-12 at 210, 3,600,and
<br /> 110 gg/L, respectively. Geomatrix recommended that a search of California Department of
<br /> Water Resources (DWR) files be conducted to identify water wells within 2,000 feet of the site.
<br /> SAIC ENERGY,ENVIRONMENT & INFRASTRUCTURE, LLC (SAIC)2005 SOIL AND
<br /> GROUNDWATER INVESTIGATION 12
<br /> On March 14 through 16, 2005, SAIC advanced four soil borings (SB-13, SB-14, SB-15, and
<br /> SB-17) and installed one groundwater monitoring well (MW-5)to further assess the extent of
<br /> affected soil and groundwater in the area of the former BPP-BTR pipelines. Additionally, DWR
<br /> files were searched to identify water wells within 2,000 feet of the site.
<br /> TPHc,TPHg, BTEX, and methyl tertiary butyl ether(MTBE)were not detected in the soil
<br /> samples from SB-13, SB-14, and SB-15, except for 120 mg/kg TPHc detected in SB-14 at 1 foot
<br /> bgs. TPHc,TPHg, ethylbenzene, and xylenes were detected in SB-17 at 42 feet bgs at
<br /> 9. Central Valley RWQCB,2007. Water Quality Control Plan(Basin Plan)for the Sacramento River Basin and the San
<br /> Joaquin River Basin,4th ed. October.
<br /> 10.Geomatrix,2002. Report of Soil and Groundwater Investigation, US Can/Welty Road, Vernalis,California. August.
<br /> 11.Geomatrix,2003. Report of Off-site Soil and Groundwater Investigation, US Can/Welty Road, Vernalis, California.
<br /> November.
<br /> 12.SAIC,2005. Soil and Groundwater Investigation Report and Second Quarter 1005 Monitoring and Sampling at
<br /> US Can—Welty Road,35275 Welty Road, Vernalis, California. October.
<br /> A-4 SAIE
<br />
|