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Attachment A:Previous Environmental Activities
<br /> SAIC ENERGY,ENVIRONMENT & INFRASTRUCTURE,LLC (SAIL) 2005
<br /> SOIL AND GROUNDWATER INVESTIGATION"
<br /> On March 14 through 16, 2005, SAIC advanced four soil borings (SB-13, SB-14, SB-15,
<br /> and SB-17) and installed one groundwater monitoring well (MW-5)to further assess the
<br /> extent of affected soil and groundwater in the area of the former HPP-BTR pipelines.
<br /> Additionally, DWR files were searched to identify water wells within 2,000 feet of the
<br /> Site.
<br /> TPHc, TPHg, BTEX, and methyl tertiary butyl ether(MTBE)were not detected in the
<br /> soil samples from SB-13, SB-14, and SB-15, except for 120 mg/kg TPHc detected in
<br /> SB-14 at 1 foot bgs. TPHc, TPHg, ethylbenzene, and xylenes were detected in SB-17 at
<br /> 42 feet bgs at concentrations of 6,700, 510, 0.2, and 2.9 mg/kg, respectively. Minor
<br /> concentrations of PAHs were detected in all of the borings. Laboratory results indicated
<br /> non-detect or low concentrations of TPHc, TPHg, BTEX, and PAHs in soil at SB-17
<br /> from 1 and 5 feet bgs.
<br /> TPHg, BTEX, and MTBE were not detected in grab groundwater samples from SB-13
<br /> and SB-14. TPHd concentrations were detected in these samples at 450 and 200 gg/L,
<br /> respectively. Several PAHs were also detected in groundwater samples from SB-13 and
<br /> SB-14. TPHd, TPHg, benzene, naphthalene, and phenanthrene were detected in the grab
<br /> groundwater sample from SB-17 at concentrations of 150,000,480, 0.6, 0.2, and
<br /> 0.1 µg/L, respectively.
<br /> SAIC collected one soil sample from SB-15 at 47 feet bgs to define the vertical extent of
<br /> affected soil off site. TPHc, TPHg, BTEX, and MTBE were not detected in this soil
<br /> sample, and thus the vertical extent of affected soil was defined at 47 feet bgs.
<br /> SAIC searched DWR files in April 2004 and identified three domestic wells located
<br /> within 2,000 feet of the former HPP-BTR pipelines adjacent to the Hunter Container
<br /> facility. One of the domestic wells was located up gradient of the former pipeline
<br /> alignments, and two were located cross gradient, approximately 1,000 feet and 1,500 feet
<br /> away. The well completion reports indicated two domestic wells were constructed with
<br /> minimum sanitary seals extending to 20 feet bgs. The well completion report of the third
<br /> well did not indicate a seal depth. One industrial well may be located in the vicinity of
<br /> the Site, but the exact location was unspecified. Municipal or agricultural water-supply
<br /> wells were not identified during the DWR search, but two wells were described on well
<br /> completion reports as public wells and were located at the Site. One well is sealed from
<br /> the surface to 150 feet, and the other to 200 feet. The DWR search did not yield records
<br /> of domestic wells down gradient(east) of the Site.
<br /> SAIC concluded that the data collected during this and previous investigations indicated
<br /> that residual petroleum had affected soil between 5 and 42 feet bgs in the vicinity of
<br /> SB-17, MW-1, SB-1, SB-2, SB-3, B-1, B-4 through B-7 (MW-2), GMX-3, GMX-8,
<br /> GMX-1B, and GMX-12. In SB-17, clay and sandy layers below 37 feet bgs appeared to
<br /> be the most affected. The lateral extent of affected soil appeared to be delineated towards
<br /> the south,west, north, northeast,and east. However,the lateral extent of affected soil
<br /> 12.SAIC,2005. Soil and Groundwater Investigation Report and Second Quarter 2005 Monitoring and Sampling at
<br /> US Can—Welty Road,35275 Welty Road, Vernalis, California. October.
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