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\ ri Mr Harlin Knoll Page 2 of 4 dedicated disposable bailers after physical parameters stabilized, and water levels recovered to at least 80% of pre-purged levels The samples were decanted into 40-m1 glass vials preserved with 1 1 hydrochloric acid solution The samples were subsequently placed in an ice chest refrigerated to a temperature of approximately 4°C The samples were transported to Argon Laboratories (ELAP 42359) under chain of custody protocol and analyzed for TPI-Ig and BTEX utilizing EPA methods 8015B and 8021B, respectively Purged groundwater was contained in labeled 55-gallon drums pending disposal Copies of field purge logs and water level measurements are included in Attachment A Drilling, Soil Sampling,and Well Installation On November 21, 2003, Spectrum Exploration (Spectrum, C57-512268) installed groundwater monitoring well MW9 under the supervision of Ground Zero geologist Sean Garvey and project manager John Lane (RG-6795) The well was installed approximately 220 feet northeast (downgradient) of the former underground storage tanks Figure 2 shows the location of well MW9 relative to the other site wells Spectrum utilized a drilling rig equipped with hollow stem augers to advance the boring and install the well A five-foot long core sampler was used to continuously collect soil samples for subjective evaluation of contamination and lithologic classification Soil encountered during drilling consisted of interbedded sand, silt, and clay Sandy soil was encountered between the depths of 6 and 10 feet bgs and 22 and 32 feet bgs No soil was retained in the sampler retrieved from the depth interval of 45 to 50 feet bgs, implying that soil in that interval is also likely sand Groundwater was initially encountered at a depth of approximately 39 feet bgs during drilling Based on the lithology and the initial depth to groundwater observed during drilling, well MW9 was screened from approximately 34 feet bgs to 54 feet bgs The well was constructed of 2-inch diameter, Schedule 40 PVC casing and 0 010 slot screen 42/12 sand filter pack was placed from the bottom of the well to approximately 2 feet above the screened interval The annular seal consisted of 2 feet of hydrated bentonite pellets overlain by neat cement grout The well was completed with a traffic-rated, grade-level well box, and a locking well cap Mr Harlan Knoll of San Joaquin County Environmental Health Department(EHD) observed field activities and inspected the grout seal A boring/well construction log is included in Attachment B All drilling and sampling equipment was decontaminated prior to use and between sample collection to minimize cross contamination Waste soil and water generated during drilling activities was placed DOT certified 55-gallon drums Both waste streams are currently stored on site pending disposal Soil samples collected at depths of approximately 35 feet and 54 feet below ground surface (bgs) were sealed, labeled and immediately placed in an ice chest cooled to a temperature of approximately 4° C The samples were subsequently transported to Argon Laboratories under chain of custody protocol and analyzed TPHg using EPA Method 8015B, BTEX and methyl-tert-butyl ether (MTBE) using EPA 8021B, and total lead using EPA 7420 Well Development and Sampling An experienced Ground Zero technician monitored the depth to groundwater and developed and sampled well MW9 on November 26, 2003 The depth to groundwater in well MW9 was 38 91 feet btoc The G 1GROUNDZEIKNOWLES HAMIREF0RTSIQMRU00314QM2003 doc