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Naw
<br /> SITE HISTORY
<br /> 1995 Soil Borings: During April 1995, Geosystem Consultants, Inc. (Geosystem) of
<br /> Irvine, California drilled eight soil borings (B-1 through B-8). Soil samples were
<br /> collected from all the borings and groundwater samples were collected from three of the
<br /> borings (B-2, B-3, and B-6). Total petroleum hydrocarbons as diesel (TPHd) were
<br /> detected in soil from borings B-1 through B-7 at concentrations up to 700 milligrams per
<br /> kilogram (mg/Kg). Total petroleum hydrocarbons as gasoline (TPHg) were detected in
<br /> soil from borings B-1 through B-3 at maximum concentrations of 1,900 mg/Kg. Benzene
<br /> was detected in soil from borings B-2, B-3, and B-6 at concentrations up to 3.9 mg/Kg.
<br /> Shallow soil samples from boring B-3 were also analyzed for total recoverable
<br /> petroleum hydrocarbons; none were detected. Grab groundwater samples collected
<br /> from borings B-2, B-3, and B-6 contained 1,600 to 12,000 micrograms per liter (gg/L) �►1�"/
<br /> TPHd, 23,000 to 150,000 gg/L TPHg, and 970 gg/L to 13,000 µg/L benzene. Details
<br /> this investigation are described in Geosystem's August 1995 Phase I and Phase II Si::(
<br /> Assessment. `IC(LOO b i 7-9)'k V1 Qu 0
<br /> 1997 Soil Borings: During April 1997, Enviros, Inc. (Enviros) of Sonoma, California
<br /> drilled five Geoprobe soil borings (SB-1 through SB-5). Soil and groundwater samples
<br /> were collected from all of the borings. ,Soil samples from all the borings contained
<br /> TPHd at concentrations ranging from 1.3 to 260 mg/Kg. Soil from borings SB-1, SB-2,
<br /> SB-4, and SB-5 contained up to 890 mg/Kg TPHg. Benzene was detected in soil from
<br /> boring SB-2 at maximum concentrations of 0.11 mg/Kg. Methyl tertiary-butyl ether
<br /> (MTBE) was reported by EPA Method 8020 in samples from borings SB-1, SB-2, and
<br /> SB-5 at concentrations up to 4.1 mg/Kg. No confirmation analysis was performed at
<br /> that time. Soil samples from boring SB-2 were also analyzed for cadmium, chromium,
<br /> lead, nickel, zinc, oil and grease, halogenated volatile organic compounds (HVOCs),
<br /> and semi-volatile organic compounds (SVOCs). This boring contained 37 to
<br /> 45 mg/Kg chromium, 7.0 mg/Kg lead, 36 to 39 mg/Kg nickel, 43 to 52 mg/Kg zinc,
<br /> 184 mg/Kg oil and grease, and 0.77 to 0.93 mg/Kg phenol. No other waste oil
<br /> constituents were detected in soil.
<br /> Grab groundwater samples were also collected from all the borings. TPHd was detected
<br /> in groundwater from all the borings at concentrations ranging from 430 to 25,000 Ag/L.
<br /> TPHg and benzene were detected in borings SB-1, SB-2,SB-4, and SB-5 at concentrations
<br /> ranging from 15,000 to 38,000 gg/L and 220 to 1,900 gg/L, respectively. MTBE was also
<br /> reported in these borings by EPA Method 8020 at concentrations ranging from 110 to
<br /> 370 pg/L. The sample with the highest MTBE reported was also analyzed by EPA
<br /> Method 8260 and none was detected (<50 gg/L). Groundwater samples from boring
<br /> SB-2 were also analyzed for cadmium, chromium, lead, nickel, zinc, oil and grease,
<br /> 240943(l) A-1 CONESTOGA-ROVERS&ASSOCIATES
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