SITE INFORMATION AND CORRESPONDENCE

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2-21-1996 10:A2AM FROM AGE NC 209 956 0700 P' 2 5 DRAFT analyzed for TPH as gasoline and BTE&X in accordance with approved EPA methods. These samples will be important in correlating PID readings and determining clean-up levels. A log book will be stored at the site for all monitoring and maintenance activities.This boot; will document all pertinent data for the project including engine running time,vapor Sow, PID readings, engine coolant levels, blower pressure levels and supplemental fuel consumption (if possible)- 3.7 Estimates! Clean-up Time Using information in the PAR, we estimate that approximately 200 gallons of petroleum hydrocarbons (gasoline) remains in the soil at the site. Based upon a very conservative recovery rate of 4 kg/day, we estimate a clew-up time of approximately 6 months (the theoretical limits of a vapor extraction system is up to 890 kglday in ideal conditions). After six months or when the efficiency of the unit has declined, an evaluation of the remediation system will be made.The evaluation will be made using FID data,soil samples, vapor samples and supplemental fuel costs.A remmmendation will be made for either site closure (soil) or continuation with remediation. If remediation is continued, additional recommendations for either continuation with the VACLEEN system or an alternate system will be made. 3.8 Confirmation Borings When the projected six-month clean-up period has been completed,or efficiency of the unit has declined, one or two soil borings will be drilled within the projected contamination plume to determine if significant soil contamination renYains.The approadmate locations of the borings are depicted on Figure 6. The borings will be drilled with a truck-mounted, hollow stem auger drill rig. The borings will be drilled to groundwater(approximately 60 feet).Soil samples will be collected at five- foot intervals using a split-spoon sampler.The sampler will be loaded with three clean,2 by 6 -inch brass sleeves. Samples will be screened in the field using a PID. Selected samples will be transported under chain-of custody to a state-certi5ed laboratory for analysis. The samples will be analyzed for TPH as gasoline and BTE&X in accordance with approved EPA methods. These samples will be used for site-closure determination. If remediation is continued beyond the projected six-month period, at Ieast one additional soil boring will be drilled after each six months of remediation system operation. o-W..„.&- I... 8