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18 November 2005 AGE-NC Project No 02-0962 Page 7 of 7 determination,the 120 µg/l TPH-g concentration was mainly from the MTBE The detected concentration of MTBE in monitoring well MW-4 exceeds the State of California's Maximum Contaminant Level (MCL)of 13 µg/l for that constituent • The lateral extent of petroleum hydrocarbon contamination is defined to the north by well MW-5, to the northeast by well MW-2, to the east by wells MW-6 and MW-1, and to the southwest by soil boring B-1 TPH had been detected at low concentrations (9 4 kg/mg TPH-g and 12 mg/kg TPH-d)in soil at southernmost soil boring B-7,but ground water at B-7 was not impacted • The vertical extent of petroleum hydrocarbon contamination is not yet defined 5.0. RECOMMENDATIONS Based on the findings of the environmental activities recounted in this report, AGE recommends continuation of quarterly ground water monitoring events, the next event has been scheduled for November 2005 Additionally, AGE recommends the installation of a deep monitoring well near r. well MW-4(screened from 70 feet to 80 feet bsg)as detailed in the AGE-prepared Additional Well Installation Work Plan, dated 24 January 2005 and approved by the EHD in a letter dated 08 February 2005 6 0. LIMITATIONS Our professional services were performed using that degree of care and skill ordinarily exercised by environmental consultants practicing in this or similar localities The findings were based upon analytical results provided by an independent laboratory Evaluation of the geologic and hydrogeologic conditions at the site for the purpose of this investigation was made from a limited number of available data points(i e , soil and ground water samples)and subsurface conditions may vary away from these data points No other warranty, expressed or implied, is made as to the professional interpretations, opinions, and recommendations contained In this report Advanced GeoEnvirnn mental,Inc