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KLEINFELDER 6 CONCLUSIONS AND RECOMMENDATIONS Kleinfelder conducted a limited soil and groundwater assessment to assess the potential impact from activities at the subject site. Based upon our findings we have formulated the following conclusions and recommendations: 1) Groundwater was encountered at the site at depths ranging from 9 to 12 feet bgs. Soil was noted primarily sand and silty sand from near surface to depths ranging from 5 to 10 feet bgs underlain by silty clays and clays in the bottom portion of most probe locations at a maximum depth of 16 feet bgs. 2) Concentrations of nitrates in soil ranged from none detected (<2.3 mg/kg) to 18,000 mg/kg. Concentrations of ammonia as N in soil ranged from none detected (<5.0 mg/kg) to 14,000 mg/kg and concentrations of TKN in soil ranged from 25 mg/kg to 10,000 mg/kg. Kleinfelder is not aware of regulatory limits existing for the above mentioned analytes in soil. The concentrations of these analytes in many soil samples are elevated and based on the relatively shallow groundwater of approximately 10 feet, this contamination is expected to impact shallow groundwater over time. 3) Concentrations of nitrate as N detected in groundwater ranged from 7.6 mg/1 (PP-10) to 15,000 mg/1 (PP-6). Concentrations of nitrate as N exceeded the State and Federal Maximum Contamination Limits (MCL) of 10 mg/1 in seven of the eight groundwater samples collected. Only the Nitrate as N concentration detected from the groundwater sample collected from PP-10, with a reported concentration of 7.6 mg/l,was below the MCL. 4) Concentrations of ammonia as N in groundwater ranged from 7.7 mg/1 (PP-3) to 24,000 mg/1 (PP-8). No MCL exists for Ammonia. However, concentrations of ammonia as N in seven of the eight groundwater samples collected exceed the Suggested No-Adverse Response Levels (SNARLS) of 30 mg/1. Only the ammonia as N concentration detected in the groundwater sample collected from PP-3 was below the SNARL. Concentrations of TKN in groundwater ranged from none detected (0.5 mg/1) to 17,000 mg/l (PP-8). No MCLs of SNARLs exist for TKN. 5) Based on the soil and groundwater sampling results it appears that past operations related to the storage of fertilizer solution from the onsite ASTs have impacted both soil and groundwater with elevated levels of TKN, ammonia as N, and nitrate as N. TKN values were reported in each of the soil samples submitted for analyses indicating a nitrate source in each of the pushprobe locations. 6) Based on soil and groundwater sampling results and sample locations it appears primary surface spills of the commercial fertilizer product have occurred primarily near the east side of Tank No. 2 and generally south of Tank No's 2 and 4 in proximity to a surface pump or piping(PP6), discharge area by PP-5, and the sump by PP-7 (southeast of Tank No. 4). 7) A nitrate and ammonia contaminant plume exists beneath the site (See Plate 3 and 4) which is oblong and irregular shaped, measuring approximately 480 by 400 feet (based on the estimated 100 ppm ammonia/nitrate as N isocontour lines). The vertical and lateral extent of 43851.E01/ST05R158/DH:Iv Page 9 of 12 02005,Kleinfelder,Inc. February 9,2005