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I 7 Mr Ron Rowe Page 2 of 5 gvapor P groundwater was also measured in or wells VW1 and VW3 through VW6 Wellhead elevations have not been determined for the vapor wells Water levels rose an average of 1 80 feet since last monitored on February 2, 2000, and are now at the highest levels recorded Groundwater flow direction was generally towards the east with a gradient averaging approximately 0 003 feet per foot A groundwater gradient map generated using the May 9, 2000 monitoring data is shown on Figure 2 Recent groundwater monitoring data are summarized in Table 1 Monitoring logs and well construction information are included in Attachment A On May 9, 10 and 11, 2000 Ground Zero collected groundwater samples from groundwater monitoring wells MW 1 through MW 11 and MW 13, and vapor wells VW 1 and VW3 through ' VW6 Except for MW9, at least three well casing volumes were purged from each well prior to sampling Physical parameters (pH, conductivity, temperature) were monitored during purging and allowed to stabilize prior to sampling Samples were collected after groundwater recharged ' to 100% of the original level Purged water was contained in 55-gallon drums approved by the Department of Transportation and stored onsite in a locked enclosure Purge logs are included in Attachment A Samples were placed on ice and transported under chain of custody to Argon Laboratories (FLAP 42359) Samples were analyzed for TPHg using modified EPA method 8015 and BTEX using EPA method 8020 Oxygenates, EDB and 1,2 DCA were analyzed using EPA method 8260 Analytical results for TPHg, BTEX and MTBE are summarized in Table 2, oxygenate results are summarized in Table 3 Attachment B contains laboratory reports and chain of custody ' documentation Groundwater Analytical Results 1 Groundwater Monitonng Wells The potentiometric surface was above the top of the screened intervals to all monitoring wells except MW13 Petroleum hydrocarbons were detected in groundwater samples collected from all wells Well MW 12 was inaccessible and not sampled, however, MW 12 has historically been at non-detectable concentration for petroleum hydrocarbons The highest concentrations of TPHg and BTEX were detected in samples collected from wells MW3, MW4, MW5 and MW13 Except for a noticeable increase in well MW2, petroleum hydrocarbon concentrations generally remained stable in wells affected by the onsite release Wells MW3 and MW4 are located along the southern boundary of the subject property and are ' affected by offsite release(s) MW7, located slightly north of MW3, and well MW11 located to the east are now apparently also affected Hydrocarbon concentrations in MW3 and MW4 are showing continual increases TPHg and BTEX concentrations are summarized in Table 2 ' roeklgmr12QM2000