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PRIVILEGED & CONFIDENTIAL Utility Clearance ' Prior to drilling, Building Analytics personnel visited the site and marked the boring location. USA and a private utility locating company were contacted to clear underground utilities at the boring location. ' Drilling and Soil Sampling ' On September 26, 1997 Building Analytics conducted the subsurface drilling and soil sampling at the subject property. The boring was advanced using a drill-rig equipped with hollow-stem augers supplied by Gregg Drilling and Testing of Martinez, California. Boring B4 was drilled to a depth of 65 feet bgs. Soil samples were collected at five-foot intervals until groundwater was encountered. The sampler was driven by a 140-pound hammer that advanced the sampler approximately 18 to 24 inches. The blow counts for ' each six inches were recorded on the boring logs. Soil samples were collected using a modified California sampler. Soil samples were collected in three six-inch long, 1.5--inch diameter brass tubes inside the sampler. ' The soil in the center-portion of the sample tube was used to describe the soil lithology. A Photovac Microtip Model No. HL-2020 photo ionization detector (PID) was used to measure volatile organic compounds (VOCs). Approximately 1/2 of the soil was removed, ' placed in a plastic bag and sealed. The sample in the plastic bag was then agitated and set aside to allow organic vapors, if present, to accumulate in the void space (headspace) of the plastic bag. The headspace was then evacuated with a PID equipped with a probe. The measurements were considered in the selection of soil samples for laboratory analyses. The PID readings were recorded on the boring log along with soil descriptions and soil classifications according to the United Soil Classifications System (USCS). Coordination and supervision of drilling and soil sampling activities were performed by a State of California Registered Geologist. The boring log is included in Appendix B. ' Following retrieval of the sampler, the bottom six-inch long tube was removed from the sampler, and the ends were covered with Teflon tape and capped with polyethylene end caps.: The sample tube was labeled with the sample number, collection date and project number, and was placed in a cooler chilled to approximately 4° C (40° F) and sent to SPL Laboratories of Houston, California via overnight courier. Sample handling, transport, and delivery to the laboratories were documented using chain-of-custody procedures, including the use of chain-of-custody forms. 1 Monitoring Well Installation Following the collection of soil samples, Boring B4 was advanced to 65 feet bgs, and converted to monitoring well MW-4. Well MW-4 was constructed with 20 feet of four- inch inside diameter (ID), 0.010-inch machine slotted, schedule 40 polyvinyl chloride ' (PVC) screen from approximately 45 to 65 feet bgs, and 45 feet of four-inch ID schedule 40 PVC blank casing from the ground surface to approximately 45 feet bgs. The annulus between the screen and the boring was filled with #2/12 Monterey Sand. The sand pack in the wells was surged with a surge block, to allow the sand to settle and draw the fine grained material out of the sand pack into the wells from the bottom of the boring to approximately two feet above the slotted portion. The wells were developed using a steel 4 197501 -S«w:kton