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Appendix B:Previous Environmental Investigations
<br /> SB-14; however, PAH levels were all below Preliminary Remediation Goals (PRGs). BTEX
<br /> constituents were detected in SB-9 through SB-14, but no concentration exceeded a PRG.
<br /> Groundwater samples were collected from MW-2, MW-3, MW-4, and SB-13, and submitted to a
<br /> laboratory for chemical analysis. Laboratory results for the samples were below laboratory
<br /> detection limits for the constituents of potential concern(COPCs). TPHd was detected in the
<br /> groundwater sample collected from SB-13 at a concentration of 540 µg/L. Ethylbenzene was
<br /> detected in SB-13 at a concentration of 0.8 µg/L, which is significantly less than the applicable
<br /> Water Quality Objectives (WQO) of 29 µg/L.
<br /> Geomatrix 2003 Site Investigation
<br /> ResonantSonic International, under the supervision of Geomatrix, advanced soil borings SB-15
<br /> through SB-21, on and adjacent to the Bellini property in August 2003. TPHc were detected in
<br /> all borings except SB-18. The maximum TPHc concentration detected was 39,000 mg/kg.
<br /> Benzene, ethylbenzene, and PAHs were detected in soil; however, no concentration exceeded a
<br /> PRG.
<br /> Geomatrix also collected grab groundwater samples from SB-15, SB-17, SB-18, and SB-21.
<br /> TPHg and BTEX were not detected in any of the groundwater samples. TPHd was detected in
<br /> the samples, with each concentration exceeding the WQO of 100 µg/L.
<br /> ARCOS PROPERTY
<br /> Geomatrix 2003 Site Investigations
<br /> Geomatrix conducted a preliminary soil and groundwater investigation in October 2003 at the
<br /> Arcos property, which had not previously been investigated. The preliminary site investigation
<br /> included a review of public records, historical maps, and aerial photographs; a geophysical
<br /> survey; an evaluation of current property conditions; and a subsurface investigation. Gregg
<br /> Drilling, under the supervision of Geomatrix, advanced soil borings ASB-1 through ASB-12 on
<br /> the Arcos property between October 20 and 28, 2003.
<br /> TPHc were detected in ASB-1, ASB-2, and ASB-4, with a maximum concentration of
<br /> 17,000 mg/kg (ASB-2 at 29 feet below ground surface [bgs]). TPHc were not detected in any
<br /> other borings. Low concentrations of BTEX and PAHs were sporadically detected in several soil
<br /> samples; however, no concentration exceeded a PRG, except benzene in ASB-2 at 29 feet bgs
<br /> and naphthalene in ASB-4 at 10.5 feet bgs.
<br /> Geomatrix collected grab groundwater samples from soil ASB-1, ASB-5 through ASB-8,
<br /> ASB-10, ASB-11, and ASB-12. TPHd were detected in the groundwater samples collected from
<br /> ASB-1, ASB-5, ASB-6, ASB-7, and ASB-11, with a maximum concentration of 2,900 gg/L
<br /> (ASB-1). BTEX were not detected in any sample. The only PAH detected was acenaphthene in
<br /> ASB-1 at 36.5 to 45 feet bgs; however, the concentration was well below the WQO.
<br /> 5. RWQCB-Central Valley,2007. Water Quality Control Plan(Basin Plan)for the Sacramento River Basin and the San
<br /> Joaquin River Basin,4th ed. October.
<br /> 6. Geomatrix,2004. Report of Soil and Groundwater Investigations,Former Vernalis Pump Station, Vernalis, California.
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