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Groundwater Monitoring Plan 5 <br /> 3.5.2 Groundwater Purging and Sampling <br /> Prior to sampling each groundwater monitoring well, the water level will be measured and the <br /> volume of water in the well casing will be calculated. A minimum of three well casing volumes will <br /> be purged using a bailer or low flow submersible pump (or equivalent methods). During the purge <br /> cycle, field measurements such as pH, conductivity, temperature, and visual observations will be <br /> recorded to verify well stabilization. The groundwater in the well will be considered stabilized when <br /> three successive field parameter measurements are within 10 percent of the previous measurement. <br /> Groundwater will continue to be purged if the field measurements have not stabilized or until a <br /> maximum of 5 casing volumes have been removed. <br /> If a well has poor recovery and goes dry during purging, the groundwater will be allowed to recover <br /> to 80 percent of it's original well volume or for a maximum of 15 minutes. The well will then be <br /> purged again and allowed to recover to 80 percent or a maximum of 1 hour prior to sampling. <br /> Instrument calibration will be conducted at the beginning of each field day, and thereafter if suspect <br /> or erroneous readings occur. <br /> Samples will be collected by submersible pump or bailer (or equivalent methods) and transferred to <br /> laboratory-provided containers appropriate for the analyses to be conducted. Samples collected for <br /> dissolved metals will be filtered at the laboratory prior to analysis. <br /> Groundwater sample will be analyzed for the following parameters: <br /> ■ Total Petroleum Hydrocarbons for diesel (YPH-d).using EPA Test Method 8015 <br /> modified for diesel. <br /> ■ Total and dissolved chromium using EPA Test Method 6010B. <br /> ■ Dissolved chromium VI using EPA Test Method 7199. <br /> 3.6 Sample Transport and Handling <br /> Sample containers will be labeled with the site name, sample identification, sample depth, date and <br /> time of sampling,and initials of the sampler. The sample will be placed in a sealable plastic bag and <br /> placed on ice in a cooler pending transportation to the laboratory. The sample information will also <br /> be logged on a chain of custody form along with the analyses to be run. The chain-of-custody will <br /> accompany the samples from the time of collection to delivery to the laboratory. <br /> P:\wp\jobs\20587\CAO GW\Vorkplm.doc—DCN 12495 January 2002 <br />