ARCHIVED REPORTS_XR0005851 CASE 2

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r Ground Water Sampling 2.6.2 Sample Custody Seal iIn cases where samples leave the RPs immediate control (shipment to laboratory, for example), a custody seal should be placed on the shipping container or on the individual sample bottles Custody seals provide prevention or easy detection of sample tampering The custody seal should bear the signature of the collector and the collection date It can be placed on the front and back of a cooler, around the mouth of a polyethylene overpack bag or on the lid of each sample container before it is taped shut for shipping Caution should be exercised in doing any of the above Experience has shown that the seal may not always adhere to some plastic coolers,and the cooler may arrive at the destination without the appropriate seal Sometimes the sample containers become wet from melting ice or condensation, thus, while their labels will stick, their custody seals may not Taping over the seal with a transparent tape generally solves this problem A ' similar solution can be applied to the cooler lids 2.6.3 Field Logbook If a sample analysis produces an unexpected or unexplainable result, it will be necessary to determine if the circumstances of sample collection, rather than a change in the ground-water quality, are responsible Examination of the field logbook is critical in this process The field logbook should document the following o Well identification, O Condition of well and surface completion, o Well depth, o Static water level depth and measurement technique, O Presence and thickness of immiscible layers and detection method, ' O Well purging procedure and equipment, D Purge volume and pumping rate, a Time well purged, U Well yield (high or low), O Well recovery after purging (slow, fast), ' O Collection method for immiscible layers, o Sample withdrawal procedure and equipment, ' o Date and time of collection, 25