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ti GROUNDWATER MONITORING On July 8, 1996, a Strath Environmental technician measured the water levels in wells MW-1 through MW-5, well RW-1, and piezometer PZ-1 No floating product was noted to any site well Groundwater monitoring data are summarized in Table 1 The depth to water measurements and the elevations of the well casings (Table 1) were used to evaluate the groundwater flow direction and gradient beneath the site Groundwater elevation beneath the site increased an average of 3 11 feet since February 2, 1996 Groundwater flow direction was generally to the east at a gradient of approximately 0 003 ft/ft as depicted on Figure 3 On July 8, 1996, groundwater samples were collected from wells MW-1 through MW-5 for laboratory analyses The field methods used are presented in Attachment 1 Field purge logs are included to Attachment 2 Groundwater samples were analyzed by Sequoia Analytical for total purgeable petroleum hydrocarbons (TPHg) using Environmental Protection Agency (EPA) Method 8015 modified, total extractable petroleum hydrocarbons (TPHd) using EPA Method 8015 modified, and benzene, toluene, ethylbenzene, and total xylenes (BTEX) using EPA Method 8020 Copies of the laboratory reports and chain of custody documentation are included in Attachment 3 Results of laboratory analyses indicated dissolved TPHg was detected to the samples from well MW-1 at a concentration of 3,700 parts per billion (ppb) No TPHg was detected in any other site monitoring wells BTEX constituents were detected to well MW-1, most notably benzene at 1,100 ppb Xylenes concentrations decreased to nondetectable levels this quarter to well MW-5 No other BTEX constituents were detected to any of the wells TPHd was detected to wells MW-1, MW-2, MW-3 and MW-5 at concentrations ranging from 62 ppb to MW-3 to 1,100 ppb to MW-1 The laboratory results of TPHd were reported as unidentified hydrocarbons to the C9- C24 range No TPHd was detected to monitoring well MW-4 Results of laboratory analyses are summarized to Table 2 SUMMARY AND RECOMMENDATIONS The groundwater flow direction and gradient was generally consistent with those evaluated during previous events Dissolved gasoline hydrocarbons were detected to the samples from well MW-1 Dissolved hydrocarbons to the diesel range were detected to wells MW-1, MW-2, MW-3 and MW-5 during the reporting period TPHd was detected to wells MW-2 and MW-3 for the first time to five quarters at concentrations just above the detection limit Dissolved TPHg and TPHd concentrations were below laboratory detection limits to monitoring well MW-4 W 194367043670QSR96 doe 2 • SIY�TN