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Geological Technics Inc Page 3 George's Service Report-Subsurface Investigation Project No 281 2 August 11, 1995 I Because every soil sample collected was not submitted for laboratory analysts, a screening process was used to gather additional information through field observation noting sediment type, especially grain size and clay content, moisture content, visible evidence of contamination, i e , color change due to reduction of iron or discoloration from hydrocarbons and other pollutants, and the readings above background on a organic vapor meter (OVM) The OVM is a field portable photo ionization detector that uses a 10 0 eV lamp to detect compounds with ionization potential below 10 0 eV (hydrocarbon range) The OVM is calibrated daily using a 100 part per million concentration isobutylene gas standard 2.0 SITE GEOLOGY Based on sediments recovered in the split spoon sampler and that observed by logging the cutting from the hand auger borings the soil profile of the site was observed to generally consist of a sandy silt and/or a clayey silt with varying amounts of very fine grained sand The sediments containing clay fines exhibited varying degrees of plasticity from non plastic and even friable to very plastic A few cores of sediments were observed to contain root tubes (some containing intact roots) of which some exhibited what appeared to be iron oxide staining In places the soil exhibited a mottled appearance which suggests that both oxidation and reductive conditions were present The soil below a depth of ten feet was observed to be saturated (the water table stabilized at approximately 9 5 feet after well development) The boring logs for the borings are attached in Appendix B 3.0 SITE HYDROLOGY On May 4, 1995 the three monitoring wells were measured for depth to groundwater by Del-Tech Geotechnical Support personnel The average depth to water was measured to be 9 51 feet from the top of casing measuring point The groundwater gradient and bearing of flow were calculated to be 0 00574 ft/ft flowing north 41°east respectively (Figure 3-Gradient Map) This hydrologic behavior is consistent with what would be expected based on surface topography (Figure 1- Vicinity Map)