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13 December 1999 <br /> AGE-NC Project No. 98-0433 <br /> Page 7 of 13 <br /> Modified. <br /> 1 • One ground water sample 'from well MW-I was transported to an independent <br /> microbiologist, Mr. A. Keith Kaufmann of Culver City, California, and was analyzed for <br /> physicochemical properties and microbiological enumeration. <br /> The results of the ground water sample laboratory analysis are.presented in Section 4.4. Ground <br /> water depth, flow direction, and gradient findings are presented in Section 4.5. <br /> 4.0. FINDINGS <br /> Soil in the area east of well MW-1 was found to contain petroleum hydrocarbons at depths of 15 bsg, <br /> lesser concentrations'were encountered at 30 feet and 35 feet bsg. Ground water was inferred to have <br /> erl flow direction and was found to be local/ impacted b petroleum hydrocarbons and <br /> a northerly Y p Y p Y <br /> oxygenated fuel additives. <br /> ' <br /> Analytical soil data from samples collected during the installation of three ground water monitoring <br /> Yt p <br /> wells on the site in May 1998, from the Ripon Farm Service investigation, will be used in the <br /> following findings (Ripon Farm Service - Quarterly Report dated ZO July 1995). <br /> ' 4.1. STRATIGRAPHY AND DEPTH TO GROUND WATER <br /> Silty sand and sand with a tan or gray color, apparently depending on hydrocarbon impact, was <br /> generally encountered from a depth of approximately 5 feet to 10 feet bsg. Gray'silty clay was <br /> present at depths between 10 and 15 feet bsg. Sand was encountered at depths of 15 and 25 feet bsg <br /> in various locations, while a coarse sand appears to extend northwest from the former UST area at <br /> a depth of 25 feet,bsg. Soil borings are depicted in Appendix A. A stratigraphic cross section is <br /> depicted in Figure 3. <br /> 1 <br /> 4.2. HYDROCARBON-IMPACTED SOIL <br /> A total of thirty-six soil samples were analyzed for TPH-g,TPH-d,BTEX and MTBE. Only twenty <br /> soil samples were analyzed for the suite of five fuel additives by EPA Method 8260 Modified. <br /> 1 TPI -g was detected in 12 of 24 soil samples analyzed. TPH-g was detected at concentrations <br /> as great as 1,300 milligram pre kilogram (mg/kg) in soil sample B5-20'. <br /> TPH-g was detected in soil samples at 20 feet bsg laterally from the former UST area north <br /> Advanced GeoEnvironmental,Inc. <br />