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Second Quarter Groundwater Monitoring Report June 2003 Boyett Petroleum,419 S.Main,Manteca,CA Page 5 TABLE 4 Laboratory Analytical Results (June 25,2003) Oxygenates/Additives B T E X TPH-G MTBE Other Oxygenates/Additives Detection 0.5 0.5 0.5 LO 0.05 0.5 0.5-5.0 Limits: 4g/L pg/L µg/L pg/L mg/L WL gg/L Analytical Method: 8260B 8260B 8260B 8260B 8015B 8260B 826013 Sample I.D. 3761-MW1-6/25/03 <2.0 <2.0 <2.0 <4.0 10.05 10,000 33 TAME 3761-MW2-6125/03 <0.5 <0.5 <0.5 <1.0 <0.05 18 <0.5-5.0 3761-MW3-6/25/03 <0.5 <0.5 <0.5 <1.0 <0A5 <0.5 <0.5-5.0 3761-MW6-6/25/03 <0.5 <0.5 <0.5 <1.0 <0.05 <0.5 <0.5-5.0 3761-MW7-6125103 <2.0 <2.0 <2.0 <4.0 <0,05 6,800 28 TAME 3761-MW86/25/03 <0.5 <0.5 <0.5 <1A <0.05 <0.5 <0.5-5.0 3761-MW9-6/25/03 <0.5 <0.5 <0.5 <1.0 <0.05 <0.5 <0.5-5.0 Unit Conversions: Anal ical ltg/L:parts per billion(ppb) BTEX=benzene,toluene,ethyl benzene,and total xylenes. mg/L:parts per million(ppm) TPH-G=total petroleum hydrocarbons,quantified as gasoline. MTBE=methyl tertiary-butyl ether EtOH=ethanol TBA=tertiary-butanol • DIPE=di-isopropyl ether ETRE=ethyl tertiary-butyl ether TAME=tertiary-amyl methyl ether 1,2-DCA�1,2-dichloroethane EDD=1,2-dibromoethane MONITOR WELL REDEVELOPMENT On July 15, 2003, a Condor representative was onsite to collect water level measurements and redevelop monitor wells MW-1 through MW-3 and MW-6 through MW-9. Attempts were made to redevelop monitor well MW-9 by surging and pumping the groundwater in the well with a surge block and pump. This redevelopment procedure was ineffective due to large volumes of medium-grained, well-rounded, and well-sorted sand infiltrating the well. The infiltration of sand resulted in a decrease of 0.10 feet in the measured total depth of MW-9. The water purged from MW-9 was light brown in color and cleared during redevelopment. No floating product, sheen, or odors associated with petroleum hydrocarbons were observed in MW-9. Heavy amounts of sand periodically interfered with the pump equipment. Based on the results of the redevelopment procedure applied to MW-9, the previous loss of MW-4 and MW-5 to sand infiltration, and the historic high sediment content observed in all the site monitor wells,the decision was made not to surge or pump the remaining monitor wells. In addition, it was determined even if redevelopment was successful, the potential benefits would be limited as water level measurements collected from the site monitor wells indicated the wells contained only two to three feet of water. All well-development equipment was cleaned prior to use by washing in a solution of laboratory-grade, non-phosphate detergent and deionized water, and double rinsing with deionized water. The purge water • discharged from MW-9 during redevelopment was placed in 55-gallon drums, sealed, labeled, and Ieft on A il� CONDOR