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4.0 RESULTS OF INVESTIGATION 4.1 Lithology Concrete approximately 3 inches thick overlies native bedding, which is primarily composed of well-graded sands, silts and clays. Soil in boring SB 1 consisted of well graded sand with clay to a depth of approximately 9 feet bgs. From 9 to 12/14 feet bgs, the soil was classified as well- graded sand, and from 12/14 feet bgs to 16 feet bgs, clayey sand. Native soil composed of silt was first encountered at a depth of approximately 9/11 to 16/19 feet bgs, in boring SB2, and coarsened to clayey sand to a depth of 21/24 feet bgs. Underlying the clayey sand, a layer of lean clay became evident to 25/29 feet bgs, which was followed by a bed containing well graded sand with clay to 31 feet bgs, the maximum depth explored. In borings S133 and S134, the strata consisted of alternating well-graded sand and silt sequences to a depth of approximately 16 feet bgs. Groundwater was present at a depth of 15 feet bgs in all borings. No physical indications of petroleum hydrocarbons were noted in the soil or groundwater samples collected, and FID readings were at non-detectable levels. Soil boring logs are included in Attachment A. 4.2 Laboratory Analysis Soil and groundwater samples were submitted to Argon Laboratory (FLAP 2359) and analyzed for total petroleum hydrocarbons as gasoline (TPHg), total petroleum hydrocarbons as diesel (TPHd), benzene, toluene, ethylbenzene and xylenes (BTEX), using EPA methods 8015 modified and 8020, respectively. In addition, groundwater samples and soil samples collected at 15, and 30 feet bgs from boring SB2 were analyzed for gasoline oxygenate additives using EPA method 8260. 4.3 Soil Analytical Results Soil samples submitted for laboratory analysis did not contain any detectable concentrations of TPHg, TPHd,BTEX or gasoline oxygenate additives. Table 2 summarizes the soil analytical results. Laboratory reports and chain of custody documentation are included in Attachment B. 4.4 Groundwater Analytical Results Groundwater samples submitted for laboratory analysis did not contain any detectable concentrations of TPHg, TPHd,BTEX or gasoline oxygenate additives. Table 3 summarizes the analytical results for groundwater. Laboratory reports and chain of custody documentation are included in Attachment B.