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Mr. Gerald Djuth,P.E. November 3, 2003 Page 3 or to optimize data quality. Although Figure 1 shows 7 borings, the actual number of borings required in the field will depend on observed conditions. Soil and Groundwater Screening Before drilling or sampling, all equipment used to generate samples will be cleaned using either high-pressure water, trisodium phosphate, or equivalent. Wastewater from decontamination will be captured and recycled through LFC's on-site wastewater treatment system. Soil samples will be collected and screened for impacts by an experienced GeoTrans field engineer or hydrogeologist. Each of the borings will be advanced to groundwater using a 2-inch diameter sampling spoon or equivalent. Samples will be collected continuously below a depth of 5 feet using a Geoprobe sampler. Immediately upon recovery, samples will be placed into resealable bags and lithologically logged using the Unified Soil Classification System. The bags will be marked with the boring location and sample depth and screened for odor. A description of impacts (if any)will be recorded on the lithologic log. Before sampling, depth to groundwater will be measured in the Geoprobe borings and in on-site monitoring wells,using an electric water level probe. Relative groundwater elevations will be measured using an engineers level. Also, the location of the boring relative to permanent site features, such as the fence corners, will be measured and recorded. This information will be combined to determine groundwater flow direction. Immediately after the boring is completed, depth to water will be measured from a stable datum, such as a stake or nail driven adjacent to the boring. The time of measurement will be recorded and a plot of time versus depth to water will be prepared in the field. The water level will be considered to be equilibrated when either the plot shows an asymptotic recovery trend, or no change is observed in the water level over a period of 10 minutes." After equilibrium water levels have been established, a groundwater sample will be collected through the Geoprobe boring,using a peristaltic pump with new polyethylene and silicone tubing, or equivalent. Soils and groundwater from the borings will be screened using odor, since the groundwater standard is odor based. Soil and groundwater samples collected at each of the boring locations will be labeled and maintained until the program is complete. At that time, soil and/or groundwater samples from intermediate points may be selected for analysis to show downgradient hydrocarbon decay. Sample selection will be based on the length of the plume and the perceived usefulness that the additional data might provide.