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Quarterly Report - 152 East 11th Street, Tracy Page 4 July 1993 to establish their elevations relative to a common datum, are compiled in Table 3 ) After the depth to groundwater had been measured in all of the Navarra wells, wells NAV-2, NAV-4, NAV-5, NAV-6, NAV-7 and NAV-8, were purged prior to sampling by pumping a minimum of five well volumes of water from them The purge water from wells NAV-2, NAV-5, NAV-6, NAV-7 and NAV-8 was decanted into closed-top, 50-gallon drums Based on data from earlier rounds of sampling, this water was expected to be clean When this was confirmed by the results of laboratory analysis, this water was discharged to the municipal sewer Purge water from well NAV-4, which was known to be contaminated, was decanted into a closed, 1100-gallon, PVC tank on the 152 East Street property where it will be stored until sufficient volume has been accumulated for its economical disposal at a permitted facility After all wells that were to be sampled had been purged, the depth to groundwater in each was measured again prior to sampling to ensure that a representative sample was obtained In all cases the water levels in the well fully recovered between the time of purging and the time of sampling Groundwater samples were recovered from wells NAV-2, NAV-4, NAV-5, NAV-6, NAV-7 and NAV-8 using dedicated, PVC bailers that had been installed during previous sampling rounds (Note These wells include all Navarra wells designated for sampling during the wet- and dry-season sampling rounds specified in the sampling plan plus well NAV-4 This well was included as a substitute for well ULT-9, access to which is no longer available to the Navarras Analysis of samples from well NAV-4 permits groundwater quality in the interior of the hydrocarbon plume to be monitored according to the requirements of the plan ) Water was decanted from the bailers 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 for transport, within 24 hours, to Chromalab Inc 's laboratory in San Ramon, California for analysis Following receipt at the laboratory, each groundwater water sample 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 . Ethylbenzene EPA Method 8020