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(s � enviros® 2.0 FIELD PROCEDURES 2.1 Exploratory Soil Borings Two exploratory soil borings (GP-1 and GP-2) were drilled and sampled on February 22, 1996 using the Geoprobe system The lithology of the Boring GP--1 was logged by an Enviros geologist using the Unified Soils Classification System and Munsell Color chart Encountered lithology is described on the exploratory boring Iogs presented in Appendix A, and a summary of the soil boring data is presented in Table 1 Boring GP-2 was an angle boring drilled at an angle of 30 degrees from vertical The lithology of GP-2 was not logged due to the drilling method used for this boring In order to keep the angle of the boring as true as possible the Geoprobe tool was pushed to the desired sampling depth where the soil sample was then collected Interval sampling in the angle boring would likely have caused deviation from the 30 degree angle This would have prevented collecting soil samples from the desired sampling location below the USTs The locations of the borings are shown on Plate 2 Soil samples were collected from the borings using a Geoprobe coring sampler for lithologic description and head-space analysis Sampling intervals were screened for the presence of organic vapors using a photo ionization detector(PID) PID readings are recorded on the boring log • The soil samples were collected in acrylic tubes, capped, labeled, entered onto a Chain-of-Custody record, and stored in a cooler with ice The samples were transported to Sequoia Analytical (Sequoia) in Redwood City, California, a state- certified environmental laboratory, for analysis The soil samples were analyzed for Total Purgeable Petroleum Hydrocarbons (TPPH) according to EPA Method 8015 (modified) and benzene, toluene, ethylbenzene, and xylenes (BTEX), and methyl tertiary-butyl ether (MTBE) according to EPA Method 8020 Additional analysis was performed on the soil sample collected from GP-2 This included Fractional Organic Carbon Content (FOC), Porosity, Permeability, and Toxicity Characteristic Leaching Potential (TCLP) for TPPH and BTEX Decontamination Procedures Drilling and sampling equipment were decontaminated prior to beginning work and between sampling intervals Drilling equipment was inspected prior to drilling 3.0 FINDINGS 3.1 Geology and Hydrogeology Lithology encountered during the drilling of the exploratory soil borings consisted primarily of clayey sand (SC), silty sand (SM), and sand (SP) to a depth of approximately 357 2