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Groundwater Quality Monitoring - 152 East 11 th Street, Tracy Page 4 <br /> surveyed in July 1993 to establish their elevations relative to a common datum, are <br /> . compiled in Table 2 ) <br /> After the depth to groundwater had been measured in all of the Navarra wells, wells <br /> NAV-2, NAV-4, NAV-5, NAV-6, NAV-7 and NAV-8, were purged by pumping a <br /> minimum of five well volumes of water from each of them The purge water from wells <br /> NAV-2, NAV-5, NAV-6, NAV-7 and NAV-8 was decanted into closed-top, 50-gallon <br /> drums Based on data from earlier rounds of sampling, this water was expected to be <br /> clean When this was confirmed by the results of laboratory analysis, this water was <br /> discharged to the municipal sewer Purge water from well NAV-4, which was known to <br /> be contaminated, was decanted into a closed, l I00-gallon, PVC tank on the 152 East <br /> Street property where it will be stored until sufficient volume has been accumulated for its <br /> economical disposal at a permitted facility <br /> After all wells that were to be sampled had been purged, the depth to groundwater in each <br /> was measured again prior to sampling to ensure that a representative sample would be <br /> obtained In all cases, the water levels in the wells fully recovered between the time of <br /> purging and the time of sampling <br /> Groundwater samples were recovered from wells NAV-2, NAV-4, NAV-5, NAV-6, <br /> NAV-7 and NAV-8 using dedicated, PVC bailers that had been installed during previous <br /> sampling rounds Water was decanted from the bailers using a valved decanting-spigot so <br /> as to completely fill clean, laboratory-supplied glassware The sample vials were then <br /> tightly closed, labeled for identification, entered into chain-of-custody control and packed <br /> on chemical ice for transport to Chromalab Inc 's laboratory in Pleasanton, California for <br /> analysis <br /> Sample Analysis <br /> Following receipt at the laboratory, each groundwater water sample was analyzed for the <br /> following suite of analytes <br /> Analyte Method of Analysis <br /> Total Petroleum Hydrocarbons EPA Method 5030/8015 <br /> (as Gasoline) <br /> Benzene EPA Method 8020 <br /> Toluene EPA Method 8020 <br /> Ethyl benzene EPA Method 8020 <br /> Total Xylenes EPA Method 8020 <br />