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t i Ms. Dot Lofstrom Page 3 of 6 • 1,3 Recent Groundwater Sampling p g Prior to the current investigation, monitoring well MW had been most recently sampled on May 31, 2000. At the request of PHS/EHD the analytical suite included TPHg, BTEX and a full VOC scan by EPA method 8260. No analytes other than 22 parts per billion (ppb) MTBE were detected in the water sample. The wellhead elevation of MW 1 was also tied to the elevations of the monitoring wells installed as part of the investigation of the adjacent 601 E. Miner site. Groundwater flowed in an easterly direction. 2.0 PROCEDURES 2.1 Permitting Prior to initiating fieldwork, well installation permits were obtained from San Joaquin County PHS/EHD and encroachment permits were obtained from the City of Stockton. All fieldwork was performed in accordance with the Ground Zero's Site Safety Plan and Quality Assurance/Quality Control Plan. . 2.2 Drilling and Soil Sampling On August 24, 2001, Spectrum Exploration (Spectrum), a State-licensed drilling company (C57- 512268), excavated a 2 x 2 x 8 foot area with an "air knife" to clear the area of subsurface utilities in the vicinity of proposed boring location MW2. Subsequently one soil boring was advanced and converted into groundwater monitoring well. The boring/well location is shown on Figure 2. All work was conducted under the supervision of field geologist Sean Garvey and project manager Greg Stahl, a California Registered Geologist. Ms. Dot Lofstrom of PHS/EHD conducted the grout inspection and observed field activities. A drill rig equipped with hollow stem augers was used to advance the boring. Beginning at depth of 20 feet below ground surface (bgs), soil samples were collected at 5-foot intervals using an 18- inch long core sampler lined with new 2-inch diameter brass sleeves, which afforded soil identification and subjective evaluation for contamination. A photoionization detector (PID) was used to monitor the presence of volatile organic compounds in the soil. Due to a complete lack of odors and PID readings of zero in each soil sample, the samples from the 26 feet and from 41 feet below grade were selected for analysis. Soil samples selected for analysis were sealed, labeled, and immediately placed in an ice chest cooled to approximately 4°C for transport to Argon Laboratory (Argon, ELAP 2359) under chain of custody protocol. Analysis consisted of gasoline oxygenate additives, 1,2 dichloroethane (DCA) and ethyl enedibromi de (EDB) using EPA Method 8260, BTEX using EPA method 8020, and TPHg using EPA Method 8015 modified. All drilling and sampling equipment was decontaminated prior to use and between sample collection events to minimize the possibility of cross contamination. I