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Emergency Remediation 2480 Tracy Blvd., Tracy, CA. • Page 14 close to the method detection limit (MDL). In the case of the latter condition, the concerned Public Works Department officials agreed to consider the discharge of such water on a case-by-case basis. In compliance with the agreement reached with the City, samples were taken from each holding tank after they had been filled with treated groundwater. The samples were recovered by submerging a clean PVC bailer to the approximate mid-height of the tank. 1 Water was decanted from the bailer using a valved decanting-spigot so as to completely fill clean, laboratory-supplied glassware. The sample vials were then tightly closed, labeled for identification, entered into chain-of-custody control, and packed on chemical ice in an ' electric sample cooler for transport to Chromalab Inc.'s laboratory in for analysis. Following receipt at the laboratory, each sample of treated water was analyzed for the following suite of analytes. Analyte Method of Analysis Total Petroleum Hydrocarbons EPA Method 5030/8015 (as Gasoline) Benzene EPA Method 8020 Toluene EPA Method 8020 Ethyl benzene EPA Method 8020 Total Xylene Isomers EPA Method 8020 ' Treated water was first released from the Baker tanks to the sanitary sewer on April 18, 1996. The discharge was by gravity flow at a maximum rate of 10 gpm. A copy of the certificate of analysis for each of the samples recovered from the tanks was transmitted by facsimile to the City of Tracy, and the approval of the cognizant Public Works Department officials was obtained before the contents of the corresponding tank was released. With the exception of two de-minimus cases, the analytical data show that none of the treated water contained any detectable concentration of any of the analytes of concern. The exceptions were samples from the first two tanks of treated water which contained barely detectable concentrations of toluene at 0.57 µg/L (parts per billion) and 1.8 µg/L. The presence of this inconsequential vestige of toluene was traced to incompletely cured glue used to attach fittings to the treatment system hoses which, to maintain the schedule of the emergency remediation program, had to be placed into service before the normal time allowed for full curing of glued assemblies had elapsed. No detectable concentration of toluene, or any other analyte of concern, was reported to be present in samples taken from any other tank of treated water.