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ti 4.2.2 Hydrocarbon Concentrations Eleven soil samples were transported to Excelchem Analytical Laboratories for hydrocarbon analysis Four were analyzed for Total Petroleum Hydrocarbons as Gasoline (TPH-g) and Diesel (TPH-d) and for BTEX, and seven were analyzed for TPH-g, BTEX, and gasoline oxygenates (MTBE, etc) The laboratory report is present in Appendix C, and the results are summarized in Table 1 4.2.3 Hydraulic Conductivity Seven samples were sent to Sierra Testing Laboratory for analysis of bulk density and hydraulic conductivity The Iaboratory report is in Appendix C, and the results are summarized in Table 2 One sample from the upper silt bed in HP-4 was analyzed This sample, HP-4-21', had a hydraulic conductivity of 4 6 x 10"' cm/sec, which is indicative of low-pertneability silt A sample from the underlying sand bed (HP-4-27') had a much higher conductivity of 6 7 x 10-4 cm/sec A sample of the underlying silt bed in VM-4 at 35' had a moderate conductivity of 3 2 x 10'6 cm/sec The coarse-grained sand bed beneath it had a somewhat higher conductivity of 7 9 x 10"5 cm/sec, and the silt bed immediately beneath this bed had a conductivity of 8 l x 10-7 cm/sec One sample was analyzed from each of the lowest two stratigraphic units the silt bed in HP-4 at 60 feet, and the very-fine-grained sand bed in VM-4 at 70 feet The silt bed had a conductivity of 8 7 x 10'' cm/sec, whereas the sand bed had a much better conductivity of 1 4 x 10-4 cm/sec The conductivity results indicate that the sand beds beneath the site have moderate permeability and yield a substantial quantity of water, whereas the volumetrically more abundant silt and clay intervals have low to moderate permeability 4.2.4 Bacterial Abundance Five samples were transported to Cytoculture Environmental Laboratory for determination of the abundance of hydrocarbon-degrading bacteria (Appendix C) Three of the samples were collected from the vadose zone and capillary fringe between the depths of 15 and 38,feet The other two samples were collected from the saturated zone Both of the latter samples had extremely low abundances of bacteria and were below the reliable detection limits of the analysis The vadose- zone samples contained somewhat higher bacterial populations, but were still quite low 4.2.5 Total Organic Carbon and Nutrients Five samples were transported to Sequoia Analytical Laboratories for analysis These samples were analyzed for total organic carbon and for bacterial nutrients Nitrogen, Phosphorus, and Potassium The laboratory report is included in Appendix C These analyses were performed in order to assess the availability of the nutrients necessary for the growth of hydrocarbon-degrading bacteria and to consider the potential for natural attenuation of the contaminants The results are 7