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Port of Stockton Groun ' ater 4- �.8 September 1987 <br /> called in a report of a leaking underground gasoline pipe. The line was <br /> uncovered and repaired, but an unknown amount of product was lost to the <br /> soil beforehand. <br /> I observed the removal of two underground tanks at ST Services on 6 <br /> August 1987. These were eac located in different areas of the <br /> facility. Ground water was visible in the bottom of the excavations for <br /> both tanks. In each case, strong gasoline odors were apparent when the <br /> tanks were removed. Ground water in the largest excavation was covered <br /> with a yellow film (see photograph in files) . Analyses of samples I <br /> took at the time show that the benzene level in the water at the largest <br /> tank was 2, 700 ppb, and at the smaller tank it was 9, 300 ppb. These <br /> results were transmitted by phone. The hardcopy is forthcoming from <br /> WESCO Laboratories. <br /> In summary, ground water contamination by fuel products and solvents was <br /> confirmed during the removal f four underground tanks in different <br /> locations at this site. The practice of emptying contaminated water to <br /> an unlined pit has resulted in soil contamination, and probably further <br /> ground water contamination. Ob ' ervations made during a 1986 inspection <br /> indicate that other incidents occurred which may also have contaminated <br /> ground water. SJLHD files contain a note that several significant <br /> spills occurred here. The amount of spillage is unknown. <br /> UNOCAL <br /> No information concerning ground water or soil quality at this site is <br /> available. A site plan shows it structure labeled as a dry well. Its <br /> use is unknown. <br /> UNION PACIFIC RAILROAD <br /> The southernmost petroleum storage facility in this area is used by <br /> Union Pacific Railroad. No information concerning ground water or soil <br /> quality at this site is available. <br /> GROUND WATER INVESTIGATION, PHASE 1 <br /> We have received a report summarizing the efforts by Woodward-Clyde <br /> Consultants (WCC) to define the 'hydrogeological setting at the Port Fuel <br /> Terminal area. The body of the report discusses results of observations <br /> collected during installation of 32 piezometers surrounding the site, as <br /> well as a discussion of some available background material. <br /> The work they have completed is preliminary to determining the entire <br /> extent of contamination at the site. Ground water flow direction was <br /> measured for January and February of 1987. Some qualitative <br /> determination of contamination extent in the piezometers was made, but <br /> at this time no mechanism is available for the measurement of <br /> contaminant levels in ground water. No monitoring wells have been <br /> installed. WCC recognizes that. they cannot presently characterize the <br /> ground water quality at the site, and states this in the conclusions to <br /> the report. <br /> RECOMMENDATIONS <br /> Activities in this area of the Port have adversely impacted the <br /> beneficial uses of ground water to an unknown extent. Impacts to surface <br />