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TEL No . Sep 23 ,96 17:17 No .022 P .02 ME IORAMDUPS CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD o CENTRAL VALLEY REGION 3443 Routier Road,Suite A Phone: (916)255-3900 Sacramento,CA 95627-3098 CAl_NET:8-494-3000 r From: Elizabeth A.ThayerTo: (am-don L.Boggs y , - UST Program Manager Associate Engineer: DATE: 23 September 1996 SIGNATURE: Subject: TrRCMEETING COMMENTS,FORMER SAFEWAYSITE,I I I I NA VY DRIVE, STOCKTON,SAN JOA QUINCOUNTY James Brathovde and I attended a Technical Review Committee(TRC}Meeting,22 August 1996,in Stockton. The purpose of the meeting was to determine whether this site is ready for closure. The Responsible Parties and their consultants presented information to the committee and atter the presentation,the committee members discussed the site. The committee majority,including Llre Regional Board,voted not to close this site In the past,the site was part of a military base(dates unknown). For a number of years(dates unknown), Safeway operated a meat pmoessing plant at the site and is the responsible party for the underground tank investigation. The property was recently sold to'tacky Farms(date unknown). Of the four tanks on site,one of the diesel tanks failed a tank test in 1987. Nine borings were drilled around the tanks with diesel contamination noted in a soil boring south of the tanks. A sandy soil layer was encountered between 6 and 13 feet,and water with floating product,was encountered in the pit 9 feet from the surface. The tank pit was overexcavated in 1988,to a depth of 24 feet. Soil contamination was noted in the southwest corner at up to 3700 ppm TPH4. When the first three monitoring wells were installed in 1987,ground water was encountered at 19 feet. No soil or ground water contamination was detected in the borings and monitoring wells,but a second sandy zone was encountered between 25 to 32 feet. Ground water samples were not collected again until October 1989,when MW-4 was installed during an investigation of the soil contamination at the southwest corner of the tank pit. Again,no ground water contamination was detected,however,soil contamination was detected southwest of the tank pit. Depth to water was 25 feet. The four monitoring wells were not sampled again until March 1991,when a Hydropunch sample was alto collected from a boring during an investigation of the soil southwest of the tank pit. Depth to water was 28 feet. All four wells contained diesel contamination at up to 370 ppb and the Hydropunch svnple contained 150,000 ppb diesel, In November 1991,MW-1,MW-2,and MW-3 were abandoned because water levels were dropping and the consultants speculated that the wells would go dry. (They would have water in them now.) The wells were also generally upgradient of the former tank pit. Two new wells were drilled;however,they were not intended to replace the abandoned wells. Four Hydropunch samples were collected whhicli contained up to 160,000 ppb diesel. Depth to water was approximately 30 feet.