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S E C ® R SMr Harlan Knoll January 14, 2004 Page 4 Attachment 3 Boring logs and well construction details are included in Attachment 4 Well completion data are also presented in Table 1 • Soil Analytical Results Soil samples for possible analysis were collected from the boreholes for wells MW-9 and MW-10 at approximate ten-foot intervals to the base to the total depth of the wells Since soil samples were previously collected at 5-foot intervals during the advancement of soil boring SB-1 to a depth of 63 feet bgs, which is located in close proximity to well MW-8, sod samples from the boring for well MW-8 were collected at 10-foot intervals, starting at a depth of 70 feet bgs Selected soil samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, total xylenes (BTEX), and methyl tertiary-butyl ether (MtBE) by EPA Method 82608 (single run) Due to an oversight, soil samples were not analyzed for additional fuel oxygenates tertiary amyl methyl ether (TAME), di-isopropyl ether (DIPE), ethyl tertiary butyl ether (EtBE), tertiary butyl alcohol (TBA), ethanol, 1,2-dichloroethane (1,2-DCA), and ethylene dlbromlde (EDB) by EPA Method 82606, as requested in the June 24, 2003 SJCEHD work plan approval letter Although results were not obtained, fuel oxygenates other than MtBE are likely not present, based on non-detectable • concentrations of petroleum hydrocarbons and MtBE reported for all soil samples analyzed Fuel oxygenates other than MtBE are typically reported at lower levels than petroleum hydrocarbon constituents and MtBE Soil analytical results are presented In Table 2 and on Figure 3 Field and laboratory procedures are included in Attachment 3 The certified laboratory analytical reports and chain-of-custody documentation are presented In Attachment 5 • Groundwater Analytical Results On December 10, 2003, the newly installed wells were developed and sampled by SECOR Groundwater samples were submitted to STL Laboratory for analysis of TPHg, BTEX, fuel oxygenates (MtBE, TAME, DIPS, EtBE, TBA, and ethanol), 1,2-DCA, and EDB by EPA Method 82608 (single run) Results are presented In Table 3, and on Figure 4 Field and laboratory procedures are included in Attachment 3 The certified laboratory analytical report, chain-of- custody documentation, and field data sheets are presented in Attachment 6 • Well Surveying On December 9, 2003, wells MW-8 through MW-10 were surveyed by Morrow Surveying, Inc , a licensed surveyor for locations and elevations relative to mean sea level Well survey data is presented in Attachment 7 FINDINGS Subsurface Conditions Soil within the deep borings consisted of alternating layers of sand and silty sand/sandy silt containing varying percentages of stiff to hard, moderate plasticity clay to the total depth explored A silty clay layer was present in all of the borings from approximately 1 5 feet to 7 feet bgs, and within the boring for well MW-8 from approximately 33 25 to 35 feet bgs A gravelly sand layer was present In the boring for wells MW-8 along the screened interval between 103 5 feet to 109 5 feet F 11ConocoPhflhps\Tosco Marketing188711Reports\Assessment Rpt doc SECOR Intemational Incorporated a