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i 14 December 2000 AGE-NC Project No 99-0559 IPage 8 of I I I41 SOIL PROFILE In general, a brown to olive-green/gray, damp sandy silt/silty clay, was encountered from surface grade to depths of approximately 35 feet bsg in each boring Generally, a brown to gray, damp silty sand/fine sand was encountered from 35 feet to 45 feet bsg A light brown to olive-green/gray moist clayey silt/silty clay was encountered from depths of 45 feet to 65 feet bsg Saturated soil was first encountered in most borings at depths between 55 feet and 60 feet bs P g Boring logs are included in Appendix A Cross sections depicting site stratigraphy and distribution of analytes are shown in Figures 3 through 6 i42 FIELD EVIDENCE OF HYDROCARBON-IMPACTED SOIL Organic vapor was detected in soil sample duplicates collected from MW2-60' at a concentration of 3671 parts per million (ppm) Organic vapor was detected in soil sample duplicates collected from boring MW3 and MW-4 starting at 15 feet to the total depth of the soil borings at 65 feet bsg 4 3 RESULTS OF SOIL SAMPLE ANALYSIS Select soil samples from the soil probe borings and soil pilot borings submitted for analysis for TPH- g, BTEX and fuel additives TPH-g and BTEX compounds were detected beneath the current UST location from 15 feet bsg to the total depth of the soil investigation(65 feet bsg) Soil samples collected from borings established around the current USTs generally had low concentrations of hydrocarbons below 40 feet bsg Soil boring MW3 had low concentrations of BTEX at 35 feet bsg The maximum concentration of TPH-g was detected in sample 132-15' at 12,000 milligrams per kilogram (mg/kg) The maximum benzene concentrations was detected in sample MW2-50' at a concentration of 55 mg/kg Other BTEX compound were detected as high as 1,400 mg/kg (B2-15') MTBE was detected at a maximum concentration of 300,000 micrograms per kilogram (µglkg) in soil sample MW2-50' Significant concentrations of MTBE were also detected in soil samples collected from boring MW3, at and below 35 feet bsg Overall the bulk of MTBE-impacted soil resides on the eastern portion of the site IAnalytical results of soil samples are summarized in Table 1 and Table 2 The laboratory reports (AAL Laboratory I D No A99122104 and MAI 29790 to 29814), quality assurance and quality control (QA/QC) reports and chain-of-custody forms are included in Appendix C I