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McDowell & Davis Towing <br /> Quarterly Groundwater Sampling Report November 2002 <br /> Page; 2 <br /> approximately 0.7 feet from the May 2002 monitoring event. A groundwater hydrograph <br /> is presented in Figure 4. <br /> Groundwater Elevations 11-11-02 <br /> Well Collar Elevation DTW GW Elevation <br /> MW-1 118.14 64.06 54.08 <br /> MW-2 118.79 64.65 54.14 <br /> MW-3 118.39 64.27 54.12 <br /> Groundwater flow was to the southwest (south 61 west) with a very shallow gradient <br /> (0.0011 ft/ft). The potentiometric surface and groundwater flow direction are shown on <br /> Figure 2 Site Map / Groundwater Flow. Low concentrations of gasoline range petroleum <br /> hydrocarbons, benzene, were detected in all monitoring wells. Toluene and xylenes, <br /> below water quality goals, were present in wells MW2 and MW3. MTBE was not <br /> reported in any of the monitoring wells. <br /> The dissolved oxygen concentrations show a very slight variation (8.6 to 6.6) a slight <br /> increase compared to past monitoring events which indicates continued biologic activity <br /> in the area of the soil contamination. <br /> Laboratory Groundwater Sample Results 11-11-2002 <br /> Sample I.D. I Gasoline Benzene Toluene E-Benzene Xylenes Oxygenates Oz <br /> MW-1 0,05 1.1 2.5 1.2 6.$ ND 7.0 <br /> MW-2 0.21 9.6 1 19 1 9.0 14.6 ND 8.6 <br /> MW-3 0.09 12.7 1 7.0 1 3.5 115 ND 6.6 <br /> ND—Non Detect NA=Not Analyzed <br /> Mg/L for gasoline pg/L for BTEX,MTBE,and 8260 Oxygenated Compounds <br /> Volatile aromatic hydrocarbons and petroleum hydrocarbons were detected in very low <br /> concentrations in all monitoring wells in the November 2002 monitoring event. Previous <br /> monitoring events have detected gasoline and gasoline constituents at concentrations that <br /> exceeded established water quality goals. Gasoline and gasoline constituents have been <br /> detected in soil samples collected at depths of 15 and 25 feet in the vicinity of the former <br /> dispenser island. Scheduled quarterly groundwater monitoring will continue. <br /> The above represents our best professional opinion as to environmental conditions at this <br /> site. These opinions were derived using data at hand, and standards of care common to <br /> the environmental consulting community in Northern California. There is the possibility <br /> that even with proper application of the above methodologies, there may exist on the <br /> subject property conditions that could not be identified within the scope of this sampling <br /> work or which were not reasonably identifiable from the available information. The <br />