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• <br /> c.W <br /> s <br /> Trsace Ati aiysis L aht)r.alory,hic• Telephone(415)783-6960 <br /> 3423 Investment Boulevard,h8 • Hayward,California 94545 Facsimile(415)783-1512 <br /> November 1, 1991 <br /> C Mr. James Lehrman <br /> DuPont Environmental Remediation Services, Inc. <br /> td 7068 Koll Center Parkway, Suite 401 <br /> Pleasanton, California 94566 <br /> la Dear Mr. Lehrman: <br /> From September 25, 1991 through October 11, 1991, Trace Analysis Laboratory <br /> received a number of soil samples for your project 40051I-SA, East Washington <br /> (a Street, Stockton. These samples were analyzed for total petroleum <br /> �s hydrocarbons as gasoline, benzene, toluene, ethylbenzene, and xylenes. <br /> 3 Chromatograms from samples with detectable amounts of gasoline, indicate a <br /> smaller portion of the more volatile compounds than contained in our gasoline <br /> calibration standard. This pattern is typical of aged gasoline which has lost <br /> some of the more volatile compounds. <br /> r A number of samples contained detectable concentrations of toluene, while <br /> gasoline, benzene, ethylbenzene, and xylenes were not detectable. This is an <br /> unusual pattern for a site at which gasoline is the most likely contaminant. <br /> p Although we did not detect toluene in our method blanks, we initiated a search <br /> for a laboratory source of the toluene. We tested reagents, glassware, <br /> f57 laboratory air, and other possible sources. No source was identified. <br /> Possible toluene contamination was identified in samples from another site and <br /> in one calibration standard. <br /> I believe that when toluene only was detected, the toluene was likely due to <br /> E-i contamination during the preparation of the sample. To help confirm this, <br /> three samples with detectable levels of toluene were reanalyzed directly, <br /> without a methanol extraction. Toluene was not detectable based on this <br /> reanalysis. Copies of the results are attached.' <br /> If you would like any additional information about these analyses, please let <br /> me know. <br /> Sincerely yours, <br /> - Lapis Dupuis - <br /> ' Vice President <br /> enclosures <br /> E-1 <br /> Founding mambor of the Association of California Testing Laboralories <br />