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r Pomba Ranch Property Quarterly Groundwater Sampling Report October 2003 Page: 2 • j flow was to the North with a flat gradient (N15E/0.066), similar to the groundwater flow j observed in the July 2003 event. Wellhead elevations, depth to water measurements, and groundwater elevations are shown below. Groundwater elevations and flow direction are located on figure 2. Cumulative groundwater elevations are shown on a hydrograph in figure 5. Groundwater Elevations 10-10-03 Well lCollar Elevation I DTW 7GW Elevation MW-1 43.45 9.48 33.97 MW-2 43.44 9.36 34.08 MW-3 45 10.08 34.92 Gasoline petroleum hydrocarbons, volatile aromatic hydrocarbons, and fuel oxygenates were not detected by the analytical laboratory in water samples collected from the monitoring wells. Laboratory analyses are located below and on Figure 3. Laborator Groundwater Sample Results 10-10-03 Sample I.D. I Gasoline Benzene Toluene E-Benzene Xylenes Oxygenates I Dissolved 02 Mw-1 <0.05 <0.3 <0.3 <0.3 <0.6 NA 0.45 • MW-2 <0.05 <0.3 <0.3 <0.3 <0.6 NA 1.22 MW-3 <0.05 <0.3 <0.3 <0.3 <0.6 NA 0.44 ND=Non Detect NA=Not Analyzed Mg/L for gasoline&DO pg/L for BTEX,MTBE,and 8260 Oxygenated Compounds Dissolved oxygen measurements were collected as part of the groundwater monitoring to provide an estimate of the level of biologic activity in the groundwater. The dissolved oxygen was measured during this monitoring event in the field (and noted on the field logs), instead of in the laboratory, using a down hole meter that provides a more accurate (and often lower) representation of the oxygen concentrations in the groundwater. Dissolved oxygen concentrations are presented in the above table and in figure 4. CONCLUSIONS AND RECOMMENDATIONS Shallow ground water flow was to the North with a flat gradient, similar to groundwater flow in previous events. Gasoline petroleum hydrocarbons, volatile aromatic hydrocarbons, and fuel oxygenates were not detected by the analytical laboratory in water samples collected from the monitoring wells. Quarterly monitoring will continue to confirm the breakdown of the remaining contaminants.