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i Site Characterization Report: 7500 West Eleventh Street, Tracy, CA. Page 14 pump islands had been previously located, and, to the extent that leakage had occurred there, down-gradient of the sites of the former underground storage tanks. MW-2 was located to the west of the location of push-probe PP-2, samples of soil and groundwater recovered from which were affected by visual and olfactory indicators of the presence of hydrocarbons. MW-2 was intended to be a short distance beyond the western t limit of a plume of fuel hydrocarbons emanating from the former pump island area. MW-3 was located so as to be a short distance down gradient of the former pump island area at which it was apparent that the majority of fuel leaks had occurred. MW-4 was located a short distance down gradient of the former fuel storage tanks and as far to the east as it could be safely situated, given the congested underground utilities in that area. (Note: Location of a monitoring well further to the east across Chrisman Road, < which would have been desirable given the clear indication from the data already available that MW-4 was located within the boundaries of a plume of affected groundwater, was prevented by the project's funding restrictions.) The locations of MW-5, MW-6 and MW-7, in the northern shoulder of West Eleventh Street, were chosen to check for the presence of analytes of concern in groundwater to the north and across that street from the former fueling station. MW-7 was located close to the site of PP-5, samples of soil from which were affected by strong visual and olfactory indicators of the presence of fuel hydrocarbons and from which a groundwater sample >: had been recovered that contained 560 µg/L of TPHg and 1,100 µg/L of TPHd. Based on that data and the distribution of hydrocarbons in soil and groundwater recovered from 1 PP-2, PP-3, PP-4, and PP-6, it was expected that MW-7 would provide a monitoring location that would be either on, or close to the central axis of the plume of affected groundwater. r -f MW-5 and MW-6 were located so as to investigate the location of the western boundary of the plume of diesel and gasoline. 4 =, Again, if the investigation program had been permitted to proceed as originally planned using the techniques of the well-established Observational Method as called for in the j Work Plan (The San Joaquin Company Inc. 1999), an additional well would have been located on the north side of West Eleventh Street, east of Chrisman Road to explore the eastern limits of the plume of affected groundwater. In addition, to explore the down- gradient limits to which petroleum hydrocarbons had migrated in the groundwater, another well would have been located on the eastern side of Chrisman Road some distance north of West Eleventh Street. 3.6.2 Soil Sampling in Monitoring Well Borin s I While the borings for the proposed monitoring wells were being drilled, the drilling equipment was used to recover soil samples in clean brass tubes at approximate 5-ft. intervals throughout the depth of each boring. Following sample recovery, each sample sic