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I A 26 April 2000 AGE-NC Project No 99-0520 Page 6 of 8 4 6 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES Water samples were collected from each well using a new disposable plastic bailer Each water sample was transferred into three 40-m1 VOA vials containing 0 5 ml 18% HCl as a sample preservative and Into one 1-liter amber bottle without preservative After collection, the samples were labeled and placed in a chilled container for transportation under chain-of-custody to IMcCampbell Analytical Laboratory(MAI) of Pacheco, California Each sample was analyzed for • TPH-g and TPH-d by EPA Method 8015 Modified and • BTEX and DIPE, ETBE, MTBE, TAME and TBA by EPA Method 8260 Modified 4 7 MONITORING WELL SURVEY tThe casing elevations of each well installed for the site for the UST investigation were surveyed relative to a bench mark at the southeastern sidewalk of the service building on the site 10 On 18 February 2000, a California state-licensed survey engineer from Baumbach & Piazza, Inc surveyed a reference point on the top of each ground water monitoring well at the site to the nearest 0 01-foot relative to the assumed bench mark at 100 feet above mean sea level (msl) The r"esults of the monitoring well survey are contained in Table 3 The surveying report (Baumbach& Piazza) is presented in Appendix C I 5.0 FINDINGS Ground water elevation and flow direction were calculated from field data, the hydrocarbon impact to ground water was assessed by laboratory analysis 1 5 1 STRATIGRAPHY AND DEPTH TO GROUND WATER ' Overall, sand was the dominant soil type encountered at the site Silty clay was encountered in the samples collected from a depth of 5 feef bsg in all soil borings Sand was generally encountered in the samples collected at a depth of 10 feet bsg Coarse sand with gravel was encountered at 15 feet and typically at 20 feet bsg Clay with sand was encountered in the samples collected from a depth of 30 feet bsg to a depth of 45 feet bsg in boring SBI. Ground water was measured at a depth of 17 feet to 23 feet bsg Bonn los are Included in . rid p g g g Appendix A A stratigraphic cross section is depicted in Figure 3 Advanced GeoEnvironmental,Inc. 1