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In August 1993, wells MW-1, MW-2, and MW-3 were momtored and sampled Analytical results showed that MW-1 had no measurable concentrations of petroleum hydrocarbons in the groundwater Wells MW-2 and MW-3 contained detectable levels of petroleum hydrocarbons A program of quarterly groundwater monitoring and sampling was begun in March 1994 In August 1995, Snuth Environmental conducted a subsurface site investigation to further define the extent of contamination in groundwater at the site Smith Environmental supervised the installation of monitoring wells MW-4, MW-5 and MW-6 These three new wells were developed and sampled along with monitoring wells MW-1, MW-2, and MW-3 Analytical results of groundwater samples from the six monitoring wells indicated the presence of elevated concentrations of petroleum hydrocarbons in the vicinity of wells MW-3 and MW-6, on the northeast corner of the site SAMPLING ACTIVITIES On July 10, 1996, groundwater samples were collected by Srruth Environmental personnel from monitoring wells MW-3 and MW-6 The locations of the monitoring wells are shown on Figure 2 Monitoring wells MW-1, MW-2, MW-4 and MW-5 were not sampled this quarter because PHS/EHD agreed in a correspondence mailed June 20, 1996 to reducing the sampling frequency of the wells to semiannual Prior to collection of groundwater samples, the depth to water, pH, electrical conductivity, and temperature were measured in the monitoring wells and recorded A minimum of three well casing volumes were purged from each well prior to sampling The wells were allowed to recover and samples were collected from each well using dedicated disposable bailers The groundwater samples collected from each well were submitted to Argon Mobile Laboratories (FLAP cert no 1873) for analysis of total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, xylenes (BTEX), and methyl-tertiary-butyl-ether (MTBE) utilizing EPA methods 8015/8020 Groundwater well purge and sample logs are provided in Attachment I ANALYTICAL RESULTS Petroleum hydrocarbon constituents were detected above laboratory method detection linuts in the samples collected from both wells sampled The samples collected from wells MW-3 and MW-6 contained TPHg at concentrations of 72,000 micrograms per liter [ug/1] and 600 ug/l, respectively MTBE was not detected in any of the wells although well MW-3 had a higher detection limit due to dilution factors A summary of analytical results is presented in Table 1 Laboratory data sheets and chain-of-custody documentation are provided in Attachment II GROUNDWATER FLOW DIRECTION Water level measurements were collected from wells MW-1, MW-2, MW-3, MW-4, MW-5 and MW-6 on July 10, 1996 Water levels ranged from 23 61 to 24 39 feet below the tops of the well w 194373*uarflyl3gr-1996 doe 2 SNrFH