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v o ASS O C I ATE S I N C . Monitoring well MW1 was purged a minimum of three well volumes until the electric conductivity, pH, and temperature stabilized. Subsequent to purging, groundwater was sampled and transferred to appropriate sample containers, using a clean, disposable bailer with a bottom- emptying device to reduce volatilization. Sample containers were then labeled with sample identification, placed on ice, and shipped under chain-of-custody to Sequoia Analytical. Field development/purge logs are presented in Attachment 1. Laboratory Analysis The groundwater sample from well MW 1 was analyzed by Argon Laboratories for total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, and xylenes (BTEX) by EPA Methods 801518020, and oxygenate fuel additives by EPA method 8260. Laboratory Results TPHg, ethyl benzene, and xylenes were detected above the laboratory method detection limits. No other gasoline constituents or oxygenate fuel additives were reported above their respective laboratory method detection limits. • Analytical results are summarized in Table 2. Laboratory data sheets and chain-of-custody documentation are provided in Attachment 2. OTHER ACTIVITIES In a letter received by ATC on January 8, 2001, PHS/EHD approved a workplan for supplemental subsurface investigation activities at the site. The approved scope of work includes the installation of five additional groundwater monitoring wells to delineate the vertical and horizontal extent of impacted soil and groundwater. The installation of the five monitoring wells is scheduled to take place on February 20 and 21, 2001, pending budget preapproval by the State UST bund. Following the installation and development of the additional monitoring wells, ATC will conduct a groundwater monitoring event on February 22, 2001. Measurement of depth to water in all wells will be completed to evaluate the direction and magnitude of-the groundwater gradient beneath the site. Additionally, groundwater samples will be collected from all six wells and will be analyzed for TPHg, BTEX, and oxygenate fuel additives. Results will be discussed in the First Quarter 2001 quarterly monitoring report. Details regarding well installation, development, and sampling activities can be found in ATC's Workplan Addendum for Supplemental Subsurface Investigation at Stagg High School, 1621 Brookside Road, Stockton, California, dated September 12, 2000. w:U 7292.00021reportsl4 qmr 2000.doc