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This quarter's measurements of groundwater elevations were contoured and indicate a delineated line between MW-1 id;n -4 The area above the delineation [me defined direcbonal flow in a north-northea�rly�nentation while the area below the delineation line defined directional flow in a northeasterly orientation The hydraulic gradient averages 0 01202 feet per foot across the well field (above the delineation line)and 0 00214 feet per foot across " the well field (below the delineation line) A groundwater elevation summary and directional flow map for the second quarter groundwater measurements are shown on Figures 4 and 5 The groundwater elevation data collected during this event is typical of the site, and is consistent with historical data and seasonal trends 52 Groundwater Sample Analysis ' This section presents the results of the most recent(12/17104)groundwater sampling event, and synthesizes these data with other data previously collected Table 2 summarizes the groundwater monitoring well analytical results from the most recent groundwater monitoring event Certified analytical laboratory reports and chain-of-custody documentation are included as Appendix C I TPH-diesel appeared in MW-1 at a concentration of 2800 ppb, a slight decrease from last quarter All other constituents were below the reporting limits = I MW-2 found continued contammabon from BTEX, TPH-diesel, and TPH-motor oils TBA, s DCA12, DIPE, TPH-gasoline, MTBE, EDB, ETBE and TAME were below the reporting ' limits r MW-3 continues to remain free of contamination I • Sj! 3 TPH-diesel and TPH- motor oils in MW4 remain below the reporting limits, while BTEX and TPH-gasoline remain consistent in their contamination levels DCA12 appeared at 108 ppb and LDIPE at 993 ppb TBA,EDB,MTBE,ETBE,and TAME were below reporting limits All groundwater samples secured by EI were logged in a chem-of-custody form, placed in an ice chest and picked up by a California Department of Health Services (DHS) certified 4 laboratory for analysis 5.3 Free Product A September 1998 sample of groundwater monitoring well MW-2 found black, floatmg oil that appeared to be typical of used motor oil Floating oil has been removed from MW-2, using disposable bailers and absorbent socks, periodically since that time Approximately 20 1 gallons of floating oil have been removed(Table 3) `} 6.0 Dicussion f 6.1 Conclusions € 5.1.1 MW-4 MW-4 was installed down gradient (at the time) from MW-2 to detect possible movement of used motor oil in the groundwater from the contamination source (former waste oil USTs at $ I