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R � k 2 . 0 GROUNDWATER FLOW DIRECTION AND GRADIENT On October 31, 2001, ASE measured the depth to water in each site groundwater monitoring well using an electric water level sounder The surface of the groundwater was also checked for the presence of free-floating hydrocarbons or sheen using an oil/water interface probe and a product thickness bailer Free-floating hydrocarbons were observed in monitoring wells MW-5, MW-6, and piezometer P-4 Groundwater elevation data is presented as Table One Groundwater elevation (potentiometric surface) contours are plotted on Figures 2, 3 and 4 Groundwater in the shallow zone (less than 20-feet bgs) has historically shown a northern flow ASE installed a "pump and treat" interim remediation system in September 2000 to influence the offsite downgradient flow pattern in the shallow zone The remediation system is causing a "coning effect" in the northern portion of the site This "coning effect" is visible in the shallow groundwater contour m a p (Figure 2) The groundwater, in general, flows toward the recovery wells Groundwater in the middle zone (55-70-feet bgs) appears to flow towards the cluster of wells near the northeastern corner of the site building which includes MW-6, MW-7, and MW-8 Groundwater in the middle zone also appears to flow to the southwest at the northern portion of the site property The groundwater flow in the deep zone (greater than 100-feet) appears to flow to the southwest this quarter at a gradient of approximately 0 00027-feet/foot Potentiometric surface differences in wells adjacent to each other but screened in different zones (such as the above mentioned monitoring wells MW-6, MW-7 and MW-8) show a decreasing hydraulic head with depth, suggesting the potential for downward groundwater flow 3 . 0 GROUNDWATER SAMPLE COLLECTION On October 31, 2001 , ASE collected groundwater samples from nine ( 9 ) of the site monitoring wells for analysis The reduction in the number of wells to be sampled was proposed in ASE's letter to the San Joaquin County PHS-EHD dated September 2, 2001 and approved during a subsequent telephone conversations with Lori Duncan of the PHS-EHD Prior to sampling, the site monitoring wells were purged of four well casing volumes of groundwater using a Grundfos pump and/or dedicated .f polyethylene bailers The pH, temperature, and conductivity of the purge water were monitored during evacuation, and san1ples were not collected Frank's One Stop Quarterly Report -- October 2001 Sampling -2-