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ccl� l 5 The conclusions of the document were that less than 500 pounds of residual contaminant exist at the site and that 89-100% of this material is confined within the former tank excavation ' The EHD reviewed the Klemfelder report and subsequent transmittals from The Learner Company and requested that a limited groundwater investigation be conducted This investigation was to include installing three groundwater monitoring wells on the ' periphery of the zone of impact to determine if significant migration of fuel related compounds was occurring These wells were to be monitored on a quarterly basis for a period of one year Following one year of monitoring, the site status was to be ' reevaluated The Learner Company contracted Clayton to develop a workplan to implement the EHD ' request The document entitled Groundwater Monitoring Well Installation and Quarterly Monitoring Workplan (Clayton, October 2002) was reviewed and approved by the EHD in a letter dated December 4, 2002 3.0 WELL INSTALLATION Soil borings were drilled on December 5, 2002 at the locations shown on Figure 3 The EHD approved workplan prescribed installation of wells to total depths of 30 feet, however, groundwater appeared to be partially confined during drilling Based on this, the three soil borings were drilled to approximately 25 feet below ground surface (bgs) Soil boring was conducted using a track-mounted hollow-stem auger drill rig with 8-mch ' diameter augers Soil samples were collected at 5-foot intervals to the total depth of 25 feet bgs in each boring One grab soil sample from the cuttings of each boring (a total of three soil samples) was collected on January 21, 2003 and submitted to Severn Trent ' Laboratories, Inc (STL) in Pleasanton, California, a California-certified laboratory, for analysis of Total Petroleum Hydrocarbons as gasoline (TPH-g) and diesel (TPH-d) and for BTEX and MTBE using USEPA Methods 8015M and 8021B Severn Trent is accredited under the California Department of Health Services Environmental Laboratory Accreditation Program (ELAP) ' TPH-g, BTEX, and MTBE were not detected in any of the three soil samples Diesel was detected at low concentrations in each of the soil samples at 10 mg/kg (MW-1), 7 1 mg/kg (MW-2), and 2 1 mg/kg (MW-3) The analytical laboratory flagged each of these ' diesel values as being a hydrocarbon that did not match the pattern of their diesel standard ' The borings were completed as groundwater monitoring wells on December 5, 2002 under a permit from the San Joaquin County Environmental Health Department The wells consist of 2-inch diameter Schedule 40 PVC casing set to a depth of 25 feet bgs A bottom sediment trap is present in each well with 0 010-inch size slotted casing extending • to 5 feet bgs (20 feet of screen) The remainder of the casing consists of 2-inch diameter ' Schedule 40 blank casing with a locking cap placed on the top of the casing A filter 3 S 1Pmj\P022531Pmject Summary and Request for Closure doe