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contents. The PID reading will be noted on the log for the boring from which the sample was <br /> collected. <br /> Samples will be collected, placed in containers, preserved, and analyzed within the time <br /> constraints of applicable local,provincial, and federal procedures. Upon collection, each sample <br /> will be labeled with a unique sample identification number, sampler's initials, date, and time, <br /> listed on the chain of custody, and then placed in a cooler with ice. Custody of the samples will <br /> begin at the time of sample collection and maintained by the sampling team supervisor until <br /> samples are relinquished to the laboratory. Laboratory analyses will be performed by a <br /> California Department of Health Services-certified laboratory. <br /> 3.3.3 Boring Abandonment <br /> Following the completion of all sampling activities, each of the direct push sampling locations <br /> will be backfilled with cement containing up to five percent prehydrated bentonite. If <br /> groundwater is encountered, the cement-grout mixture will be tremied into the open boring. The <br /> tremie pipe will be placed approximately two feet above the bottom of the open boring until <br /> undiluted grout flows from the boring at the ground surface. If the tremie pipe must be raised <br /> during grouting,it will remain submerged at least 10 feet below the surface of the grout. Each of <br /> the borings will be marked with a traffic cone until the cement has set, and the surface restored to <br /> a reasonable facsimile of the surrounding surface area. <br /> 3.3.4 Groundwater Sampling <br /> Grab-groundwater samples will be collected by bailing a sample from within the drive casing, a <br /> driven stainless steel screen, or from a temporary casing and screen installed in a cased or open <br /> boring. The bailed sample will be immediately decanted to a container appropriate for the <br /> analysis to be performed, as shown in Table 2. Labeling and handling of the grab samples will <br /> be similar to the protocol used for soil samples. <br /> 3.4 GROUNDWATER MONITORING <br /> Three groundwater monitoring wells are used to characterize groundwater quality in the former <br /> UST area. Versar will collect samples from the wells to assess the present condition of <br /> groundwater. In the 2000 PA/SI, Versar recommended closure of the wells due to the minimal <br /> impact to this groundwater resource which is not used in the AASF area. Data from this <br /> groundwater sampling event will be used to further substantiate closure for this issue. <br /> Each monitoring well will be purged of approximately three casing volumes of water, the water <br /> level allowed to recover to at least 80 percent of the pre-purge level, and then the wells will be <br /> sampled. During purging activities, the pH, temperature, and conductivity of the purged water <br /> will be monitored and recorded at regular intervals to assess the influx of representative <br /> formation water into the well. Data collected prior to and during purging and sampling will be <br /> 9 <br /> 3027-03/104700.4766.230/JUL23'03 <br />