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No HVOCs, other than the PCE and 1,2-DCP, were detected in any of the groundwater samples collected on-site It should be noted that 1,2-DCA, which has been detected in off-site domestic wells downgradient of the site, has not been detected in groundwater samples collected from any of the on-site monitoring wells Groundwater samples collected from recovery wells RW-1 through RW-5 contained up to 140,000 ppb TPH-G, 840 ppb benzene, 18,000 p p b toluene, 4,500 ppb ethyl benzene, 25,000 ppb total xylenes, 8,100 p p b MTBE, 21 ppb TAME, 1,100 ppb TBA, and 380 ppb ethanol It should b e noted that the highest TPH-G, BTEX and TBA concentrations were detected in groundwater samples collected from recovery well RW-1 to the west, and the highest MTBE concentration was detected in groundwater samples collected from recovery well RW-5 to the east Since the highest hydrocarbon concentrations are present in the recovery wells to the outside (RW-1 to the west and RW-5 to the east), it is not known at this time whether the full extent of the plume is being captured with these existing wells 9 . 0 GROUNDWATER ELEVATIONS AND FLOW • The round surface elevation and to of casing elevation g p g of the n e w groundwater monitoring and recovery wells were surveyed relative to mean sea level (msl) by Farley Surveying, Inc of Stockton, California on September 27, 2000 The northing and easting location of the wells a n d piezometers were surveyed relative to the California Coordinate System The benchmark used for this survey was the USGS M 1164-1960 brass c a p at the southeast corner of Airport Way and West Yosemite Avenue The survey information is presented in Appendix H Depths to groundwater were measured in each well prior to sampling on September 25, 2000 with an electric water level sounder Depth t o groundwater measurements are presented in Table Four, and groundwater elevation (potentiometric surface) contours are plotted on Figures 10, 1 1 and 12 On September 25, 2000, groundwater in the shallow zone (less than 19-feet bgs) appeared to flow primarily to the north beneath the site at a gradient of approximately 0 001-feet/foot Groundwater in the 55 t o 70-feet bgs zone flowed primarily to the south/southeast at a gradient of 0 003-feet/foot Groundwater in the deeper zone (below 100-feet bgs) flowed to the southeast at a gradient of 0 0018-feet/foot Franks One Stop Report — November 2000 -16-