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------------- <br /> V I <br /> A S S O C I A T E S I N C . <br /> =' 2.1 Soil Borin Advancement and Sarn lin <br /> Drilling was conducted on March 9, 1999 by V & W Drilling (State C57 license no. 720904) <br /> utilizing a hollow stem auger drill rig. Soil boring MW-4 was advanced to 28 feet bgs and soil <br /> borings MW-5 and MW-6 were advanced to 26 feet bgs. Soil samples were collected at five-foot <br /> intervals or significant changes in lithology using a 2-inch diameter split-spoon sampler containing <br /> three brass tubes. A photoionization detection meter (PID) was used as a field-screening device <br /> for the detection of petroleum hydrocarbon vapors. Soil borings MW-4, MW-5, and MW-6 were <br /> =-_-i completed as groundwater monitoring wells. A field geologist logged drill cuttings and soil <br /> samples utilizing the Unified Soil Classification System. Descriptions of soil types encountered <br /> and sample collection intervals are included on the boring/well construction logs contained in <br /> Appendix A. Drill cuttings were temporarily stored on site in 55-gallon DOT approved steel <br /> drums. <br /> 2_2 Soil Sample Analysis <br /> Selected soil samples were placed on ice and transported under chain-of-custody to Sequoia <br /> Analytical (FLAP #1210) of Redwood City, California for analysis. All soil samples were <br /> analyzed for total petroleum hydrocarbons as gasoline (TPHg), and benzene, toluene, <br /> _ ethylbenzene, and xylenes (BTEX) utilizing EPA 8015 and 8020 methodologies, and oxygenate <br /> >s-f fuel additives utilizing EPA 8260 methodology. The analytical results for soil samples are <br /> summarized in Table 1. Laboratory data sheets and chain-of-custody documentation are included <br /> -' in Appendix B. <br /> 2.3 Groundwater Monitoring Well Construction <br /> Soil borings MW-4, MW-5, and MW-6 were subsequently completed as groundwater monitoring <br /> wells to assess impacted groundwater beneath the site, and to provide additional measurement <br /> E--# <br /> points for the determination of groundwater flow direction and hydraulic adient. The new <br /> p g Y �' <br /> wellheads were surveyed on March 11, 1999 and tied to the existing monitoring wellhead <br /> elevations. Survey data is contained in Table 3. <br /> Each well was constructed with 2-inch PVC casing to depths of 26 feet bgs. The screened <br /> r- interval of each well was positioned from approximately 5 feet above to 15 feet below the <br /> encountered water table to allow for seasonal water level fluctuations. The screen slot size is <br /> 0.020 inch. Well construction details are depicted on the well logs contained in Appendix A. <br /> 2.4 Monitoring Well Development <br /> :j Groundwater monitoring weIIs MW-4, MW-5, and MW-6 were developed on March 11, 1999. <br /> -a Each well was purged until the extracted water was relatively sediment free. Development/purge <br /> logs are included in Appendix C. Purgewater was temporarily stored on site in 55-gallon drums. <br /> After fluid levels had been allowed to stabilize, groundwater levels were obtained from wells <br /> F'-J MW-1 through MW-6. Fluid levels were taken on March 11, 1999, utilizing an electronic water <br /> wa130991reports\sumwet.doc 3 <br />