|
i
<br /> ' ARCADISURAGKTY&MILLER
<br /> adjacent to the waste oil tank. Maximum concentrations of petroleum hydrocarbons
<br /> were detected in samples taken from approximately 20 feet below ground surface
<br /> The two samples with the highest detections, samples KB3 and KB5, had TPHg
<br /> ' concentrations of 239 0 and 370.0 mg/Kg, respectively. Sample KB3 indicated
<br /> concentrations of BTEX compounds at 112, 18 0, 18 2, and 41.9, respectively.
<br /> Sample KB5 indicated concentrations of BTEX compounds at 6 58, 38 6,40 1, and
<br /> 53 15,respectively-
<br /> During tank removal between March and April, 1988, a significant amount
<br /> of soil was excavated from the site. Soils within the tank excavation were removed
<br /> ' to a depth of 30 feet. The results, reported by Applied Geosystems (Report
<br /> Subsurface Investigation, No. 38012-5, Applied Geosystems, December 12, 1990),
<br /> indicated that total petroleum hydrocarbons calculated as gasoline (TPH-g) in soil
<br /> ' samples taken from the excavation, with one exception, ranged from less than 2 to
<br /> 38 mg/Kg and concentrations of benzene(B)ranged from nondetect to I.72 mg/Kg
<br /> One soil sample taken from the west end of tank T-I at 16 feet below ground surface
<br /> ' (bgs) indicated a TPHg concentration of 582 mg/Kg and benzene (B), toluene (T),
<br /> total ethylbenzene, and txylenes (X) concentrations of 0.60, 6 50, 10 40, and 39 10
<br /> mg/Kg,respectively A soil sample taken from beneath the product line were found
<br /> to have a TPHg concentration of 6 mglKg No benzene was detected in the product
<br /> line sample After additional excavation was conducted,a soil sample taken from 26
<br /> feet bgs indicated a TPH concentration of 13 m and BTEX concentrations of
<br /> 0 29, 107, nondetect, and 132 m �g
<br /> mg/Kg, respectively. No hydrocarbons were
<br /> ' detected beneath the waste oil tank
<br /> Between June 1988 and February 1992, Applied Geosystems (AGS) and
<br /> RESNA Industries installed I 1 soil borings (B-1 through B-11) Seven of the
<br /> bonngs were completed as monitoring wells (IVIW-1 through MW-7)and three were
<br /> completed as soil vapor extraction (SVE) wells (VW-1 through VW-3) Monitoring
<br /> ' Wells MW-1, MW-2, MW-3, and MW 6 are located on site and Wells MW-4,
<br /> MW-5, and MW-7 are located northeast (downgradient) of the site The SVE wells
<br /> are located in the vicinity of the former product islands
<br /> A SVE test was performed in March 1992 by RESNA (Vapor Extraction
<br /> Test Results, letter report, RESNA, January, 4, 1993) RESNA reported that the
<br /> ' results of this test sbow that, with a wellhead flow rate of 43 cubic feet per minute
<br /> (cfrn), an estimated radius of influence of approximately 25 feet could be achieved
<br /> for one vapor extraction well
<br /> ' In July 1994, Pacific Environmental Group,Inc.(PEG)installed two off-site
<br /> monitoring wells (MW-8 and MW-9), (Groundwater Monitoring Well Installation,
<br /> Ietter report, Pacific Environmental Group, October 4, 1994) Sample results from
<br /> ' these monitoring wells indicated that the lateral extent of dissolved hydrocarbons in
<br /> Cho re!_ Page
<br /> "*Ao! SANTA BARBARA%DATAVIPRO_SBO%UNOCALvc VALLEAWPS RF VIPACWKPZkDOC 3/11
<br />
|