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4� <br /> 10 August 1999 <br /> • AGE-NC Project No. 98-0520 <br /> Page 4 of 6 <br /> tools and brass sleeves used for sample collection were thoroughly washed in a solution of Alconox <br /> and rinsed with clean tap water prior to each sampling run. <br /> 4.0. FINDINGS <br /> Soil descriptions (lithologies), were determined from field data. Hydrocarbon impact in soil and <br /> groundwater,was characterized from field and laboratory analytical data. <br /> 4.1. SOIL PROFILE <br /> A brown to olive grey, damp, silty sand/sand with silt,was encountered from surface grade to depths <br /> of approximately 20 feet bsg in each boring. In boring B-1 a mixture of wet, grey to olive grey silty <br /> sand and clayey silt was generally encountered from 20 feet to 40.25 feet bsg. <br /> Saturated soil was first encountered in each boring at depths between 15 feet and 20 feet bsg. Boring <br /> logs are included in Appendix A. <br /> 4.2. FIELD EVIDENCE OF HYDROCARBON-IMPACTED SOIL AND GROUND WATER <br /> Organic vapor was detected in soil sample duplicates collected from B-4-20' and B-2-20.25' at <br /> concentrations as.high as 185 and 200 parts per million(ppm), respectively. Additionally, significant <br /> organic vapor detection occurred in soil sample duplicates.collected from borings B-1 and B-3. <br /> 4.3. GROUND WATER DEPTH AND GRADIENT <br /> Based on field data collected onsite ground water depth is approximately 17 feet bsg. The regional <br /> ground water flow direction, or gradient is inferred to be toward the northwest. But, both ground <br /> water depth and flow.direction can be locally influenced. <br /> 4.4. RESULTS OF SOIL SAMPLE ANALYSIS <br /> Select soil samples from borings B-1, B-2, B-3, and B-4 were submitted for analysis for TPH-g, <br /> TPH-mo, BTEX and MTBE. The laboratory results reported petroleum hydrocarbons TPH-g, TPH- <br /> mo, BTEX in sample _B-2-20.25' at concentrations as high as 670 ppm, 120 ppm; 13 ppm, <br /> Advnnred GeoEnvironmental,Inc. <br />