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KLEINFELDER 5 DISCUSSION OF RESULTS The probe locations advanced as part of this soil and groundwater assessment were selected by Kleinfelder with direction by Mr. Tom Kramer of IRM and in consideration of subsurface utilities. The primary emphasis of the assessment was near AST No. 2 and in proximity to potential impact areas including pumps, discharge areas, sumps and subsurface piping. Based on groundwater analytical results Nitrate as N and Ammonia as N isocontour maps have been developed (See Plates 3 and 4). This assessment has not included an assessment of groundwater flow, as only grab groundwater samples were collected and survey points were not obtained. The following is a discussion of analytical results and field observations. 5.1 SOIL SAMPLING ANALYTICAL RESULTS Concentrations of ammonia as N detected in soil samples at the subject site ranged from none- detect (ND) to 14,000 mg/kg. Nitrate as N ranged from none-detect to 18,000 mg/kg and TKN concentrations ranged from 25 mg/kg to 10,000 mg/kg. The highest concentrations of nitrate as N and ammonia as N were detected from push probe boring location (PP6 ) at a depth of 5.5 feet bgs located southeast of Tank No. 2 and near a surface pump. Other locations with elevated concentrations of each of the requested analytes (nitrates, ammonia and TKN) in soil (above first encountered groundwater) includes PP7 and PP8 located near a sump structure and between Tank No's 2, 5 and 6, respectively. Elevated concentrations of these same analytes were also detected in PP1 at 11 foot depth, but this sample was likely collected beneath first encountered groundwater and therefore may be influenced by the groundwater contaminant plume discussed below. Therefore these elevated concentrations from PPI at 11 feet bgs may not be only a result of surface infiltration at this specific location. TKN values were reported in each of the soil samples submitted for analyses indicating a nitrate source in each of the pushprobe locations. The highest TKN concentrations in soil above groundwater was primarily detected from pushprobes PP-5, PP-6, PP-7 and PP-8, located near Tanks No's 2 and 4 , near a surface pump, a sump and product discharge area, located generally south of Tanks Nos. 2 and 4. 5.2 GROUNDWATER SAMPLING ANALYTICAL RESULTS Concentrations of Ammonia as N detected in groundwater samples at the subject site ranged from 7.7 milligrams per liter(mg/1) to 24,000 mg/l. Nitrate as N ranged from 7.6 mg/l to 15,000 mg/l and TKN concentrations ranged from none-detect to 17,000 mg/l. Nitrate as N and ammonia as N isocontour maps were developed based on the analytical data. Please note however that the extent of the contaminant plume has not been defined either laterally or vertically, although attenuation with lateral distance is shown based on the data obtained. Therefore a 0-line for both isocontour maps is not included. The highest concentrations of ammonia as N and TKN were reported from push probe sample location PP8 located between Tank No's 2, 5, and 6. The highest concentration of nitrate as N 43851.E0I/ST05RI58/DH:Iv Page 7 of 12 ©2005,Kleinfelder,Inc. February 9,2005