SITE INFORMATION AND CORRESPONDENCE_FILE 1

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with a pre-cleaned Teflon bailer. Before sampling, the bailer was rinsed with deionized water, and three bailer volumes of ground water were discharged before water was collected into 40- ml vials for specific volatile analysis and into 1 -quart amber glass bottles for analysis for total petroleum hydrocarbons (TPH ) . The vials and bottles contained hydrochloric acid as a preservative. Samples for volatiles analysis were collected in a way that would ensure that there were no air bubbles in the ` bottle. All bottles were immediately closed with Teflon-lined caps, labeled, placed on ice, and with a chain of custody form, sent within 24 hours to the laboratory for analysis. All wells were located, gauged, and surveyed, and a map showing the ground-water direction under the site was developed (Figure 7 ) . Well and surface elevations were surveyed, using as a datum the sidewalk surface at the south corner of the site with elevation of 8 . 5 feet above sea level (taken from the USGS topographical map, 1 : 24, 000, Stockton West Quadrangle ) . Figure 8 is a generalized cross-section of the site. Soil and water samples were analyzed for TPH and selected gasoline volatile organic compounds. These values are included in Table 2, which is a summary of previous and recent analyses of soil and ground water. Soils were analyzed for TPH using the modified EPA 8015 method (GC-FID) and for VOA using the EPA 8020 method. Fuel hydrocarbon and its volatile constituents were 6. below detection limits ( 10 ppm for TPH; 50 ppb for VOA) . The results of soil analysis and field observations confirm that soil above the saturated zone is practically free of hydrocarbons. L Soil samples collected from below the water table and analyzed (well MW7 - 27 feet ) did not contain hydrocarbons above the L detection limit. L 19