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i This quarter's measurements of groundwater elevations were contoured and indicate a delineated line between MW-1 and MW4 The area above the delineation line defined directional flow in a northeasterly orientation while the area below the delineation line defined directional flow in an east-southeasterly orientation The hydraulic gradient averages 0 0015 j feet per foot across the well field(above the delineation line)and 0 0015 feet per foot across the well field(below the delmeation line) A groundwater elevation summary and directional flow map for the second quarter groundwater measurements are shown on Figures 4 and 5 1 The groundwater elevation data collected during this event is typical of the site, and is j consistent with historical data and seasonal trends I i 5.2 Groundwater Sample Analysis This section presents the results of the most recent(06116104)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 TPH-diesel appeared in MW-1 at a concentration of 4800 ppb, an increase from last quarter All other constituents were below the reporting limits MW-2 found continued contamination from MTBE, DIPS, TPH-diesel, and TPH-motor oils 1 DCA12, measured for the first time, appears at a concentration of 185 ppb BTEX and TPH- gasoline reappeared at concentrations lower than previous quarters EDB, ETBE and TAME were below the reporting limits MW-3 continues to remain free of contamination i TPH-diesel and TPH- motor oils in MW4 remain below the reporting limits, while BTEX and i TPH-gasolme remain consistent in their contamination levels DCA12 and EDB, measured for ( the first time,appear at concentrations of 315 and 4 36 ppb respectively ' All groundwater samples secured by EI were logged in a Cham-of-custody form, placed in an ice chest and picked up by a California Department of Health Services (DHS) certified ' laboratory for analysis 5.3 Free Product A September 1998 sample of groundwater monitoring well MW-2 found black, floating oil that appeared to be typical of used motor oil Floating oil has been removed from MW-2, using j disposable bailers and absorbent socks, periodically since that trine Approximately 19 9 ' gallons of floating oil have been removed(Table 3) i I � a F • i