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�• Mr. Ron Rowe Page 2 is shown on Figure 2. Groundwater monitoring data for the Valley Volkswagen well are presented in Table 1. Groundwater monitoring data for 601 East Miner Avenue are presented in Table 2. Monitoring well construction details are listed in Table 3. Prior to sampling, approximately three well casing volumes were purged from monitoring well MW I. Temperature, pH and electric conductivity were measured while purging. Samples were collected after parameter stabilization, and 100%water level recovery. Purge water was contained in an appropriately labeled DOT-approved 55-gallon drum, which is currently being stored onsite. The purge log for MW 1 is included in Attachment A. Groundwater samples were delivered under chain of custody protocol to Argon Laboratories (FLAP #2359). Analysis consisted of BTEX by EPA method 8020, TPHg by EPA method 8015 and gasoline oxygenate additives and VOCs by EPA method 8260. Analytical Results TPHg, BTEX, and VOCs were at non-detectable concentrations. MTBE was detected at a level of 22 parts per billion (ppb) a decrease of approximately 50 percent since last sampled. No other gasoline oxygenate additives were detected. Analytical data are presented in Table 4. Laboratory data reports and chain of custody documentation are included in Attachment B. Rationale for Closure No TPHg, BTEX or VOCs were detected in the water sample from MWI. • The low levels of MTBE detected in the groundwater from well MW 1 are decreasing and approaching the California primary MCL. The lateral and vertical extent of soil contamination has been defined. Soil contamination is confined to an area of approximately 700 square feet within close proximity to the former UST location. Impacted soil is present between the depths of approximately 17.5 and 32.5 feet below grade. The contaminant consists of highly weathered gasoline range hydrocarbons depleted in BTEX. Since the installation of MW I in May 1995, groundwater levels have risen into the zone of residual soil contamination; however, no TPHg/BTEX currently exists in well MW 1 or was detected in boring HP4, which was located immediately downgradient of MW 1. This provides evidence that soil in the vicinity of the tank pit is not leaching contaminants into the groundwater. We do not believe that the low Ievels of TPHg (180 ppb) and benzene (27 ppb) detected in the grab water sample from boring HPI are indicative of contamination originating from the site. Soil samples collected from MWl and the initial, disturbed, water sample from MW 1 both contained TPHg without any detectable benzene. Benzene comprised 15% of the sroLmazewn V,gm20W