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, • GROUNDWATER MONITORING On January 23, 1997, a Smith Technology technician measured the water levels in wells MW-1 through MW-5, well RW-1, and piezometer PZ-1 No floating product was noted in any site well Groundwater monitoring data are summarized in Table I 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 4 12 feet since October 21, 1996 Groundwater flow direction was generally to the northeast at a gradient of approximately 0 004 ft/ft as depicted on Figure 3 On January 23, 1997, 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 in 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 in the sample from well MW-1 at a concentration of 4,700 parts per billion (ppb) No TPHg was detected in any other site monitoring wells Benzene, ethylbenzene and xylenes were detected in well MW-1, most notably benzene at 1,900 ppb Toluene decreased to a nondetectable level (<25 ppb) in MW1 for the first time since monitoring of the well began in December 1988 Benzene and toluene concentrations increased to concentrations of 0 65 ppb and 0 90 ppb, respectively this quarter in well MW-5 Benzene was detected in MW5 for the first time since August 1995, and toluene was detected for the first time since monitoring of the well began in October 1993 No other BTEX constituents were detected in any of the wells TPHd was detected in wells MW-1, MW-2, MW- 3 and MW-5 at concentrations ranging from 67 ppb in MW-2 to 1,200 ppb in MW-1 TPHd concentrations in MW3 increased to the highest levels since monitoring of the well began in December 1988 The laboratory results of TPHd were reported as unidentified hydrocarbons in the C9-C24 range No TPHd, TPHg, or BTEX were detected in monitoring well MW-4 Results of laboratory analyses are summarized in Table 2 SUMMARY The groundwater flow direction and gradient was generally consistent with those evaluated during previous events Dissolved gasoline hydrocarbons were detected in the samples from well MW-1 Dissolved hydrocarbons in the diesel range were detected in wells MW-1, MW-2, MW-3 and • MW-5 during the reporting period TPHd concentrations in well MW3 increased to the highest w 194367194367\IQSR97 doc 2 • SMTH