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• 4.0 RESULTS 4.1 Stratigraphy Boring JLM-2, which was drilled approximately 5 feet west of the 1995 remedial excavation (Figure 2), has been projected into Figure 3, a cross section that was drawn along the west wail of the excavation for the Site Remediation Report This section illustrates the site stratigraphy and the stratigraphie position of the samples from JLM-2 In 1995,ten stratigraphzc units were identified in the excavation walls (Units 1 and 8 were not evident on the west sidewall), and samples from JLM-2 are representative of five of these units The log of this boring is included in Appendix A Very-fine-grained to silty gray sand was recovered from JLM-2 at a depth of 10 feet This sample came from the lower part of Unit 2, which was mapped from the surface to approximately 11 feet on the west side of the remedial excavation In the excavation, Unit 2 was underlain by gray, clayey to sandy silt that was mapped as Unit 3 This unit was a few feet thick at the north end of the excavation but appeared to thin and pinch out southward(Figure 3) Boring JLM-2 apparently penetrated Unit 3 at a depth of 15 feet, encountering clayey, brownish-gray silt As shown in Figure 3, Unit 4 is a thin bed that was not sampled in JLM-2 This unit was described in the excavation walls as coarse-to-medium-grained, locally gravelly, sand . Underlying Unit 4 are several feet of brown clay that was noticeably weathered, locally cemented by caliche, and rooted in the excavation sidewalls In the Site Remediation Report, this unit was interpreted as an ancient soil (weathered B and C horizons) Sample JLM-2-20' was probably from the upper part of Unit 5 (Figure 3), although it was somewhat coarser grained, consisting of brown, fine-to-medium-grained clayey sand Samples at 25, 30 and 35 feet in JLM-2 all consisted of gray sand, ranging from very fine to medium grained These samples appear to be most characteristic of Unit 7, however,the upper contact of Unit 7 was mapped at 26 feet (1 foot below sample JLM-2-25') and the lower contact of this unit was mapped at approximately 32 feet(3 feet above sample JLM-2-35') Hence,the upper and lower contacts of Unit 7 in Figure 3 are probably off by 2-3 feet 4.2 Field Evidence of Contamination As noted on the boring logs (Appendix A), moderate to strong hydrocarbon odors were evident in JLM-2 to at least 25 feet PTD readings ranged from 1275 to 1800 parts per million (ppm) in these samples, but decreased to only 15 ppm at 30 feet and 8 ppm at 35 feet During the 1995 remedial excavation work, moderate to strong gasoline odors were detected in Units 2-5 from approximately 10 to 25 feet below grade During the subsequent sampling of the sidewalls, no odors were detected below 25 feet in Units 7- 10, matching the results from JLM-2 No hydrocarbon odors were detected in JLM-1, and PID readings were below 5 ppm for all samples 4