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30 FIELD SERVICES AND LABORATORY ANALYSIS Geocon performed groundwater monitoring and sampling on October 2, 2003 to determine water table elevation and the distribution of dissolved hydrocarbons in groundwater monitoring wells Two offsite domestic wells were sampled to determine if potable water supplied to adjacent residents are impacted with petroleum hydrocarbons Groundwater elevation data and contaminant concentrations in groundwater are reported in Tables 1 and 2 Operation and maintenance (O&M) services were performed for the SVE and ozone sparge systems ' for the reporting period between July 16 and October 15, 2003 ' 31 Water Table Elevations And Gradient On October 2, 2003, Geocon personnel measured the depth to water in each of the ten Site-related groundwater monitoring wells A water level indicator was used to gauge the wells to the nearest ' 0 01 foot A groundwater elevation contour map indicates that groundwater flow was generally toward the south at a gradient of 0 002 ft/ft as depicted in Figure 4 Groundwater monitoring data is presented in Table 1 32 Quarterly Groundwater Samplinir Groundwater monitoring wells were purged using a submersible pump until pH, temperature, and conductivity readings had stabilized Temperature, conductivity, and pH readings were recorded for Meach well for each casing volume removed using a field instrument Water purged from the wells is stored in a 500-gallon above ground storage tank within the remediation system compound Domestic wells DW-2R and DW-3 were purged by opening a spiget at the well head woi ks, draining the well's holding tank, and allowing the tank to re-fill with fresh water pumped from the aquifer ' Once the tank had been recharged, water samples were collected directly from a spigot at the holding tank Domestic wells DW-211, DW-3, and DW-4 are on a quarterly sampling schedule and DW-1 is ' on a monthly sampling schedule However, the residence that is serviced by domestic well DW-4, located at 23665 South Santa Fe Road, was served with an "Eviction and Restoration Notice " Thus, the home at 23665 South Santa Fe Road was vacant and no serviceable line to the potable water ' supply was available at the time of the quarterly sampling event Onsite domestic well DW-1 has nitrate concentrations that exceed the drinking water standard San Joaquin County Environmental ' Health has requested the abandonment and replacement of domestic well DW-1 The replacement is scheduled for October 2003 Based on the abandonment schedule, Geocon did not collect a sample from DW-1 in October 2003 Fiee floating product was observed in each monitoring wells MW-1 and MW-3 The free product was measured in each well to be approximately 114 inch thick Due to the presence of free product no groundwater samples were collected from MW-1 and MW-3 Protea No 58643-06 01 -4- NovuTiber 3,2003