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Project No 034-98081 Page No 5 respectively Fuel oxygenate constituents were also analyzed by PPA Method 8260 in each groundwater sample Analytical results are presented in Tables IV and V (Appendix A) Copies of the Certified Analytical Results and Chain-of-Custody Record are provided in Appendix C ' Theroundwater g quality data from the current and previous investigations has been combined on Figure 4, which posts benzene and TPH-G values at each boring or well Based on this data distribution, a groundwater plume boundary has been drawn Review of the map shows that plume definition has been accomplished in all directions except to the northwest of monitoring well MW-1 5 5 Chemical Constituent Distribution and Relationships The analytical data from Krazan's monitoring well groundwater samples mimic previous anomalous grab groundwater data This anomalous data was discussed extensively in section 6 2 of Krazan's August 28, 1998 report for Phase I of the current investigation The samples contain a petroleum material that elutes within the early retention tune for gasoline chromatograph, however, the material does not snatch a gasoline "fingerprint " As with the groundwater samples from Phase I of our subsurface investigation, the exaggerated ratio of benzene compared to toluene, ethylbenzene and xylenes from monitoring well groundwater samples is quite distinct from that expected or commonly observed for a gasoline source Krazan has obtained analytical chromatograms for the soil samples from our initial set of soil borings at the former UST location (Geoprobe© boring P-2 at 10 and 20 feet bgs) and from our initial grab f� groundwater sample from beneath the UST location (P5-W) Please refer to Figure 2 for locations A review of these chromatograms (Appendix F) shows that soil samples exhibit the general "shape" of that expected for a gasoline release, with normal BTEX ratios Review of the groundwater sample chromatogram, collected essentially directly beneath these soil samples, exhibits a chromatographic pattern quite different in its few but distinct peaks and in the ratio of benzene (labeled 3T on the chromatogram) to the remaining chemical constituent peaks Compai ison of these chromatograms suggests whereas the former gasoline UST is a plausible source for the contamination noted in soils beneath it, some other non-gasoline source is suspected as the cause of groundwater contamination beneath the UST and at other locations on-site KRAZAN & ASSOCIATES, INC Offues Serving the Western United States 3498081 sg2