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' Monitoring Well Destruction and
<br /> Soil and Groundwater Investigation Report
<br /> US Can—Welty Road
<br /> September 24, 2009
<br /> intended purposes (i.e., delineation,risk evaluation). The evaluation determined that all
<br /> analytical data are usable. See Appendix E.1 for more information. Qualified data with reason
<br /> codes are provided in Tables 1 through 4, and summarized in Appendix E.1, Table E.1.
<br /> 5. DISCUSSION OF PETROLEUM DISTRIBUTION
<br /> 5.1 EXTENT OF AFFECTED SOIL
<br /> Soil analytical results were compared to the lowest, most conservative RSL and ESL
<br /> concentrations for delineation purposes. Numerous soil sample analytical results obtained in the
<br /> course of this investigation exceeded the respective RSLs and ESLs; therefore, the results are
<br /> summarized briefly below and provided on Tables 1 and 2.
<br /> e TPHc were detected in excess of the ESL in SB-18, SB-20 through SB-26, SB-28, SB-29,
<br /> and SB-34.
<br /> • Benzene, ethylbenzene, and total xylenes were detected in excess of the respective RSLs
<br /> in SB-21; ethylbenzene was also detected in excess of the RSL in SB-29.
<br /> 1 • Various PAHs were detected in excess of the respective RSLs and ESLs. The most
<br /> commonly detected PAHs were benzo(a)anthracene, benzo(a)pyrene,
<br /> benzo(b)fluoranthene, and naphthalene.
<br /> 1 • Separate-phase hydrocarbons (SPH) were observed in borings SB-38 through SB-41 and
<br /> SB-43; however, soil samples collected just above the capillary fringe in these borings
<br /> did not exceed screening levels for TPHc.
<br />' These exceedances and previous data indicate that there are three distinct areas of affected soil,
<br /> hereinafter referred to as Area 1, Area 2, and Area 3 (from south to north), as depicted on
<br /> Figures 3a and 3b.
<br /> 5.2 EXTENT OF AFFECTED GROUNDWATER
<br /> Groundwater analytical results were compared to the lowest, most conservative ESL and WQO
<br /> concentrations for delineation purposes. The groundwater sample analytical results are briefly
<br /> summarized below, and are provided in Tables 3 and 4.
<br /> 0 SPH were observed in borings SB-20, SB-21, SB-24, SB-25, SB-26, SB-28, SB-29,
<br /> SB-34, SB-38 through SB-41 and SB-43.
<br /> 0 TPHd were detected in excess of the ESL and WQO in SB-18, SB-19, SB-22, SB-23,
<br /> SB-24B, SB-25, SB-29, and SB-42.
<br /> • TPHd after silica-gel cleanup were detected in excess of the ESL and WQO in borings
<br />' SB-18, SB-22, SB-23, SB-24B, and SB-29;
<br /> a Several PAHs, including benzo(a)anthracene, benzo(b)fluoranthene, chrysene and
<br /> dibenz(a,h)anthracene, were detected above the respective ESLs and WQOs in
<br /> groundwater in the borings.
<br /> • Generally, the largest number of PAHs and the highest concentrations were detected in
<br /> SB-23 and SB-29.
<br /> 7 ==
<br /> From Sclence to Solutions
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