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No Further Action Required Request Report
<br /> Tracy Byron Road-Tracy,California December 1,201 I
<br /> 5. Provide scaled site maps of the area impacted showing locations of former and existing
<br /> tank systems, excavation and sample locations, boring and monitoring well locations,
<br /> rgroundwater elevation contours,subsurface utilities, buildings, streets, and any nearby
<br /> surface waters.
<br /> ' The locations of current structures,former pipelines,and sampling locations are shown on
<br /> Figure 2. The affected areas at the Site encompass approximately 27 acres. Areas 1,2, and
<br /> 3 measure approximately 200 feet by 1,400 feet, 375 feet by 2,000 feet, and 200 feet by 650 feet,
<br /> respectively. The extent of affected soil and groundwater is indicated on Figure 3. No
<br /> monitoring wells were installed at the Site,and therefore, no groundwater elevation contours
<br /> were generated.
<br /> 6. Provide boring logs and cross-sections to show site lithology.
<br /> Boring logs from the SAIC environmental investigations are provided as components of
<br /> Appendices B.l through B.3. No cross sections have been generated.
<br /> 7. Report the volume of excavated soil disposed off-site, or remaining on site.
<br /> Soil excavation has not been conducted with the exception of minor amounts of soil removed
<br /> during investigation activities. No investigation-derived waste remains on the Site.
<br /> 8. Describe the fate of any remaining monitoring and remediation wells (destroyed,
<br /> ownership transferred, or to remain in use).
<br /> No monitoring or remediation wells were installed at the Site.
<br /> 9. Provide tabulated results of all groundwater elevations and depths to water.
<br /> ' During the SAIC investigations, static depths to water at the Site were reported between 10 and
<br /> 25 feet bgs. Surveying the surface elevations of soil borings was not a component of any
<br /> previous investigation;therefore,groundwater elevations have not been calculated.
<br /> 10. Provide tabulated results of all sample analyses, including the sampling method and
<br /> detection limits. Analytical results must include TPH and BTEX constituents, lead,
<br /> MTBE,EtBE, TBA,ETRE,DIPS, TAME,ethanol, methanol, ethylene dibromide, 1,2-
<br /> dichloroethane, and other constituents as indicated in Table#2 above. Provide any WET
<br /> or TCLP results.
<br /> Soil and groundwater analytical results for the COPCs(TPHc, BTEX, and PAHs)are included as
<br /> Appendix C. Lead,MTBE,EtBE,TBA,ETBE,DIPE,TAME, ethanol, methanol,ethylene
<br /> dibromide, and 1,2-dichloroethane are not COPCs,and were therefore not analyzed. WET and
<br /> TCLP tests have not been performed on soil samples.
<br /> 11. Discuss concentration and mass changes over time, and current concentrations of
<br /> contaminants remaining in groundwater at the site.
<br /> SAIC identified three areas of affected soil and groundwater covering a total of 27 acres.
<br /> Significant changes of plume size or COPC concentrations, if measurable, would not be expected
<br /> on a quarterly, semi-annual,or even an annual basis. Thus, a monitoring-well network was not
<br /> installed to track plume stability or concentration trends. Current concentrations of the COPCs
<br /> at the Site are likely to be less than levels recorded during previous investigations due to natural
<br /> attenuation of the residual hydrocarbons. The concentrations of COPCs do not pose a threat to
<br /> 7 SAIL
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