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Project No 034-98081 Page No 8 for this constituent Therefore, it appears that soil contamination attributed to a release of ' gasoline from the former UST is restricted to an area roughly constrained by the locations of boreholes R-1, P-4, P-3, and B-1 • Groundwater contamination appears to be restricted to the locations of boreholes B-2 and B-3, and earlier borehole P5-W (see Figure 2) No PHCs were detected westward or eastward of the former UST at borehole locations B-4 through B-7 Again, chemical constituent ratios, ,represented by very high benzene only concentrations, suggest a non-gasoline component dominates the PHCs detected at boreholes B-2 and B-3 Therefore, groundwater contaminants attributed to a release of gasoline from the former UST appear to be restricted to a similar area as that noted above for soil contaminants i * The areal distribution of contamination trending northwest-southeast across the site, the observation of possibly more permeable materials at depth along this trend, the non-gasoline "signature" of contaminants detected, and the lack of known use of a predominantly benzene- based substance by Wilbur-Ellis suggests a possible off-site source for much of the contaminants detected Based on the above conclusions, the following recommendation is made ' Installation of three permanent groundwater monitoring wells requested by SJCEHD should proceed as scheduled The proposed locations of the wells (shown on Figure 2) are such that confirmation and future monitoring of the contaminants noted it boreholes B-2 and B-3 is optimized Potentiometrc surface maps constructed from groundwater elevation data, and confirmation of currently perceived chemical constituent distribution will help determine if there is an off-site component to the contaminants detected 1 ' KRAZAN & ASSOCIATES, INC Offices Serving the Western United States 3498081 SGS