ARCHIVED REPORTS XR0009817 - Laserfiche WebLink

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' 3.2 Sample Collection and Analysis Water samples were collected from each well using disposable plastic bailers Each sample ' was collected in three 40-m1 EPA vials and one 1-liter amber bottle The samples were then placed in a chilled container and transported under chain-of-custody procedure to Western ' Environmental Science & Technology (WEST) in Davis, California Each water sample was analyzed for total petroleum hydrocarbons (TPH as gasoline and ' diesel) and BTE&X in accordance with EPA methods 8015m and 602, respectively ' TABLE 1 RELATIVE GROUNDWATER ELEVATIONS ' Depth to Groundwater Relative Groundwater Relative Elevation Well No Casing 3/94 6194 3193 6194 ' Elevation MW-1 4971 1072 1150 3899 3821 ' MW-2 4840 932 1011 3908 3829 MW-3 4874 948 1025 3926 3849 MW-4 4694 815 896 3879 3798 'All measurements m feet ' 4.0 FINDINGS ' 4.1 Groundwater Elevation and Gradient The elevation of groundwater in each well was calculated by subtracting the groundwater ' depth from the surveyed casing elevation (Table 1) The depth to groundwater at the site ranges from 9 to 115 feet Groundwater depth at the site has decreased approximately 0 75 feet since the March 1994 monitoring This decrease is consistent with seasonal (summer) decreases in groundwater depth in the area The flow direction continues to be north-northwest, the gradient steepens from ' approximately 0 0025 ft/ft at the south end of the site to 0 0050 ft/ft north of the site (Figure 3) ' 4.2 Petroleum Hydrocarbon Impacted Groundwater TPH as gasoline and diesel were detected in MW-1 at concentrations of 560 ppb and 320 ppb, respectively Benzene, toluene, ethylbenzene and xylenes were also detected in MW-1 at concentrations of 22 ppb, 5 2 ppb, 23 ppb and 89 ppb, respectively G_1*0-1 Aide ScN ink tic / 661 MTEWAR7'1 BBAMN OR 6.94 (�