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1 3 RESULTS Results of the June 2004 monitoring event are presented in Tables 1 and 2 and are also summarized in Figures 1 and 2 Complete laboratory reports are reproduced in Appendix B For comparative purposes, cumulative potentiometric elevations are presented in Table 4 and cumulative groundwater results for TPHd and TPHg and BTEX are included in Table 5 During the June 2004 monitoring event all seven wells contained water and were purged and sampled for analysis Potentiometric elevations for the site varied from -2 28 to -2 52 ft below MSL We interpret the groundwater flow direction to be toward the south The groundwater gradient was calculated to be approximately 0 0009 ft/ft in June 2004 These results are consistent with values measured during previous groundwater sampling events The highest value of TPH as diesel this quarter was 16,000 µg/L in monitoring well MW-2 Historically, the highest value of TPH as diesel at this site was 94,000 gg/L detected at MW-2 in May 1999 ' This quarter, TPH as gasoline was detected in two wells and was not detected in five wells The highest value of TPH as gasoline this quarter was 16,000 µg/L in monitoring well MW- 2 Historically, the highest value of TPH as gasoline at this site was 370,000 lig/l_ detected at MW-2 in September 2001 This quarter, toluene was detected in three wells and was not detected in four wells The highest value of toluene this quarter was 600 wg/L in monitoring well MW- 3 Historically, this value represents the highest value for toluene detected at this site Benzene, ethylbenzene and xylenes were not detected in groundwater samples collected this quarter The toluene result at MW-3 is inconsistent with historical analytical data at the site (toluene has generally been non-detect), and appears anomalous given the absence of any benzene, ethylbenzene, or xylene detections A thin layer of free product was encountered in MW-2 during this quarter's sampling activities A thin layer of free product was also encountered in MW-2 during the previous groundwater monitoring event in June 2002, as well as other monitoring events in 2000 and 2001 Additional groundwater sampling needs to be conducted to confirm the results from this quarter's groundwater monitoring event, particularly the toluene results at MW-2 and the TPHd results at MW-5 and MW-6, given that this is the first groundwater monitoring event to be conducted in two years The next round of groundwater sampling is scheduled for the third quarter of this year G IProjects129629 StocktoMJune 2004 Quarterly Monitoring Reporffinal braft\Penny Newman June-04 TEXT doc i 1AUY& i ALDFJCH 6