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Appendix B Advanced AGE Project No. 99-0559 Environmental Page 8 of 12 n.M 9 In addition, the cleaning solvent TCE was detected in samples CPT5-70 and CPT8-70 at concentrations of 1,700 pg/I and 10 pg/I, respectively; CPT-5 and CPT-8 are the westernmost borings of the investigation. HU4 Samples CPT4-90, CPT5-100, CPT6-100, CPT7-100 and CPT8-100 were collected from HU4. TPH-g was detected in samples CPT4-90, CPT6-100 and CPT8-100 at concentrations of 2,000 pg/I, 450 pg/I and 180 pg/I, respectively. The fuel additive MTBE was detected in samples CPT4-90, CPT6-100 and CPT8-100 at a maximum concentration of 2,600 pg/I (CPT4-90); ETBE and TAME were detected in CPT4-90 at 25 pg/I and 5.6 pg/l, respectively; and TBA and DIPE were detected in CPT8-100 at 630 pg/I and 18 pg/I, respectively. In addition, the solvent TCE was detected in samples CPT5- 100 and CPT8-100 at concentrations of 5.2 pg/I and 9.1 pg/I, respectively. BTEX compounds were not detected in the HU4 samples. HU5 Upper Samples CPT4-120, CPT5-130, CPT6-125, CPT7-130 and CPT8-125 were collected from Upper HU5. TPH-g was detected only in sample CPT6-125 at 190 pg/I, and the fuel additive MTBE was detected in samples CPT4-120, CPT6-125 and CPT8-130 at a maximum concentration of 91 pg/I (CPT6-125). No other analytes were detected in the Upper HU5 samples. HU5 Lower Samples CPT5-150, CPT6-150, CPT7-150 and CPT8-165 were collected from Lower HU5. The fuel additive TBA was the only analyte detected in the Lower HU5 samples, at a concentration of 180 pg/I. • TPH-g was detected is groundwater samples collected in HU2, HU4 and Upper HU5; the maximum concentration was 2,000 pg/I in HU4. BTEX compounds were detected only in HU2. • Fuel additives were detected in all hydrologic units. The highest concentrations were detected in HU4; MTBE was detected in HU4 at a maximum concentration of 2,600 pg/I, ETBE and TAME were detected at 25 pg/I and 5.6 pg/l, respectively, and TBA and DIPE were detected at 630 pg/I and 18 pg/I, respectively. However, only TBA was present in Lower HU5, at a concentration of 180 pg/I. HU4 is a thick poorly graded sand layer encountered at approximately 90 to 110 feet bsg. MTBE is apparently migrated laterally within this unit, especially off-site towards the west. • Dissolved MTBE extends off-site past all current sampled locations. The concentrations of dissolved MTBE decreased away from the site, except to the west at CPT4, the highest concentration of MTBE detected off-site.