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� v 0 A S S 0 C I A T E S I N C 2.2 Soil Sample Analysis Selected soil samples were placed on ice, and transported under chain-of-custody to Sequoia Analytical (ELAP #1210) of Redwood City, California for analysis All soil samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg), total petroleum hydrocarbons as diesel (TPHd), and benzene, toluene, ethylbenzene, and xylenes (BTEX) utilizing EPA 8015 and 8020 methodologies, and oxygenate fuel additives utilizing EPA 8260 methodology The analytical results for soil samples are summarized in Table 1 Laboratory data sheets and chain- of-custody documentation are included in Appendix B 2.3 Groundwater Monitoring Well Construction Soil borings MW4 and MW5 were completed as groundwater monitoring wells to assess impacted groundwater beneath the site, and to provide measurement points for the determination of groundwater flow direction and hydraulic gradient Each well was constructed with 2-inch PVC casing to 35 feet bgs The screened interval of each well was positioned from approximately 5 feet above to 15 feet below the encountered water table to allow for seasonal water level fluctuations The screen slot size is 0 020-inch Well construction details are depicted on the well logs contained in Appendix A The two new wells and three existing wells were surveyed on July 16, 1999 to an arbitrary elevation Survey data is contained in Table 2 2.4 Monitoring Well Development Groundwater monitoring wells MW4 and MW5 were developed on July 16, 1999 Each well was purged until the extracted water was relatively sediment free Development/purge logs are included in Appendix C Purge water was temporarily stored on site in 55-gallon drums After fluid levels had been allowed to stabilize, groundwater levels were obtained from wells MW1, MW2, MW3, MW4, and MW5 Groundwater elevation data are presented in Table 2 2.5 Groundwater Sampling and Analysis On July 16, 1999, groundwater samples were collected from wells MW4 and MW5 The samples were collected after purging a minimum of three well volumes and stabilization of electric conductivity, pH, and temperature Field development/purge logs are presented in tAppendix C Subsequent to purging, groundwater was sampled and transferred to appropriate sample containers, using clean, disposable bailers with bottom emptying devices to reduce volatilization Sample containers were then labeled with sample identification, placed on ice, ' and shipped under chain-of-custody to Sequoia Analytical w 1130991reporMsumweh doc 3