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20 October 1998 AGE-NC Project No. 98-0470 Page.S of 7 4.0. FINDINGS 4.1. . STRATIGRAPHY In the general area of the former UST,brown silt and silty sand were encountered from surface grade to depths of approximately 25 feet bsg. Fine to medium sand was encountered at depths between 25 and 30 feet bsg. Silt was encountered from 30 feet bsg to total depth of the well at 65 feet bsg. The soil boring log is included in Appendix A. taw 4.2. DEPTH TO GROUND WATER The.depth to ground water in the well at the site was static at 35.35 feet bsg. Saturated soils were encountered at a depth of 52 feet bsg. Ground water flow direction in the area of the site is inferred to be toward the northeast,based on the map titled Lines of Equal Elevation of Groundwater Spring ti... 1996 published by.the San Joaquin County FCD&WCD and other local subsurface investigations. �- 4.3. HYDROCARBON-IMPACTED SOIL. The results of laboratory analysis of soil samples collected at the site over the last quarter are as follows: • TPH-g wasdetected in samples from depth of 20 feet bsg and 50 feet bsg at concentrations of 800 mg/kg (milligrams per kilograms or parts per million: ppm) and 1.6 ppm, respectively. Benzene was only detected in soilsample MW1-50 at a concentration of 0.24 ppm. • Toluene,ethyl benzene and xylenes were detected in soil samples at concentrations as great �. as 37 ppm, 17 ppm and 87 ppm, respectively. • TPH-g and BTEX were not detected in the soil sample collected from a depth of 65 feet bsg �. in soil boring MW-1. • MTBE was the only oxygenated compound detected in soils at the site and was detected in sample MW1-35 at a concentration of 0.055.ppm. Laboratory results of soil samples analyzedfor petroleum hydrocarbons area summarized in Table -. 1.The laboratory reports(MAI Laboratory ID 92522 to 92526),quality assurance and quality control (QA/QC)reports and chain-of-custodyform are included in Appendix'C. Advanced GeoEnvironmental,Inc.