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was most likely correct. A head space analysis was performed on soils rem v_ from the probe tip at point SG-17, these results are given in the analytical results table. _ Of the 22 probes placed, all 22 required drilling through approximate! of reinforced concrete. At three locations sampling r t? inches pil approximately 6 inches because of resistance duringdrillin points were moved Patched by placing ready mix concrete into the holes, g AN the holes were Sample facations, times and identifications are presented in the d enclosed. The file names presented in the daily fogs identify the ologs, chromatograms. orlogs, Results - Of the 22 sampling Points analyzed at a depth of 5 feet, 21 samples detectable quantities of NPH mples showed combination of Poor P of these 21 samples, 4 samples had a impossible. p peak sha a and concentration which made p These 4 samples have been listed as <0.2 ng/ml and 1quantitation g/ I in the results table. The two samples collected at 13 feet showed decreased levels compared to samples collected at five feet in the same location. g/ml Concentration levels ranged from 90,000 ng/ml in SG-5 at the south e tank to 0.07 ng/ml at sample end of the collected. Concentrations within 1pS eel of tfaeh gasolinehea k excwesterty sampl® SG-1, SG-5 and SG-19 were the only samples with NPH conentrations ovation, samples than 10 ng/mf and were 2$, greasier collected to the south of the tank, SG-6 to dSG-9 we150 �emrelativ respectfully. ent and averaged 6.o e so hofTVPSamples high concentrations tear the tank excavatioe exceptn, and the 3 samples cons with s relatively r" SG-17, levels of BTX were below 5.0 ng/ml. These mpleshe dalsooex analysis at a chromatography similar to that of a breakdown product of a heavier on poor Typical chromatograms of these samples are attached. e.. contaminant. Conclusion The fairly dry hard clays encountered at this site had a sufficientlylow Porosity to reduce and/or eliminate flow of vapors horizontally through subsurface. It should also be noted that the Henry's Lays effethe ctive r' ry Constant for gasoline a measure of the moderately of a compound to vaporize from an aqueous Solution) is only moderately favorable for gasoline. Taking these factors consideration, the results obtained at this site may not truly represent the-actual- From ctu - - - - conditions in the subsurface. ors into of - - - -- — -- -- -- From the data collected, it appears that the clayey sail has limited t migration of the gasoline to the area ime horizontal gasoline tank. The samplmediately surrounding thee collected at the north end of the excavation d SG-1, orr-soosoj