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• a r Second Quarter Groundwater Monitoring Report June 2003 Boyett Petroleum,419 S.Main,Manteca,CA Page 2 Table 1 Summary of June 2003 Quarterly Groundwater Monitoring Results Field Activity Number of Uoundwater wells 9 Number of oundwater wells sa led 7* Number of groundwater wells 9 Date(s)monitored and sampled 6/25/2003 monitored Site Hydrology Average depth to groundwater below monitoring well measuring 20.79 feet Average increase(+)/decrease(—)in +2,82 feet Dints depths to groundwater since last sampling (Deeper) Approximate flow direction and 0Southwest as calculated using monitor oundwater gradient .00$5 ft/ft wells MW-2,MW-6, and MW-8. Groundwater Contamination Monitor wells containing free 0 Monitor wells with detected petroleum 0 product hydrocarbon odors MTBE Maximum concentrations detected in the Nature of contamination: Gasoline monitor wells: Oxygenates/ MTBE(µg/L) 10,000 Additives TAME(gg/L) 33 * Monitor wells MW-4 and MW-5 were not sampled FIELD OBSERVATIONS On June 25, 2003, a Condor representative was on site to measure water levels and collect groundwater samples from monitor wells MWA, MW-2, MW-3, MW-6, MW-7, MW-8, and MW-9. Monitor wells . MW-4 and MW-5 are damaged and slated for destruction; as a result, water level measurements and groundwater samples were not collected from these two monitor wells. The locations of the monitor wells are shown in Figure 2, attached. Field observations included water level measurement (Table 2, on the following page), appearance of samples (color, clarity, and presence of petroleum product sheen or phase in samples), and collection of water quality field parameters. Field observations are included on the Groundwater Monitoring Field Forms, attached. No floating product, sheen, or odors associated with petroleum hydrocarbons were observed in the groundwater purged from the monitor wells during the collection of groundwater samples. A moderate "cedar" odor was noted in monitor well MW-2. Clarity was good in all of the field inspection samples, with the exception of MW-1 that had moderate clarity, and MW-6 and MW-8 that had poor clarity. The purged groundwater from MW-1, MW-2, MW-3, MW-7, and MW-9 turned brown with poor clarity. GROUNDWATER ELEVATIONS AND GRADIENT Groundwater elevations fluctuated relative to the previous quarterly monitoring event(March 2003). The average groundwater elevation decreased with respect to the previous quarterly monitoring event by 2.82 feet. Groundwater elevation data is presented in Table 2, on the next page, and historic groundwater elevation data is attached. j �"� CONDOR