Protocol for the Collection, Transfer and ANSI/AARST MW-RN 2020 Measurement of Radon in Water 17 SECTION 6.0 FIELD OPERATIONS— HANDLING WATER SAMPLES 6.1 Forward samples immediately to the laboratory Informative advisory —Collectors should coordinate collection, transport, and measurement of the sample with the laboratory. When samples are shipped to a laboratory to be analyzed, the sample should be packaged and shipped within 24 hours of collection or at the first available opportunity. Note—Due to the relatively short half-life of radon, analytical measurement of a water sample commonly commences within 4 days (96 hours) from the time of collection in order to be considered a valid test result. 6.2 Sample transport Informative advisory —For both local handling and shipping, be aware that: a) Breakage of glass sample containers may occur (due to freezing) during winter months. b) Bubbles can form in the sample-collection bottles when exposed to heat during summer months. These bubbles can impact test reliability. See Section 5.4 and Table 11.1.5 . c) Packaging of water samples for mailing should include containment (e.g., sealable bag) and sufficient absorbent to prevent wetting of adjacent mail in case of breakage. d) Mailing of cocktails containing liquid scintillation fluid should be avoided. 6.3 Temperature during sample storage and transport Informative advisory —The person responsible for handling the samples in the field (and in the laboratory) should take measures to avoid compromising the integrity of the sample that can result due to the temperature in the environment where the sample is stored or transported. The solubility of dissolved gases in the water is directly related to its temperature. Groundwater taken directly from a well will be below 60˚ F (15˚ C). While the water sample does not need to be kept cooler than the initial (extracted) temperature, whenever possible the sample should be stored, transported, and shipped in a cool environment to minimize the formation of bubbles, since dissolved gases may come out of solution if the sample is warmed. Some U.S. states may require the use of coolers. Alternatively, when water samples are susceptible to freezing, expeditious handling and transference to the laboratory is advised. 6.4 Bubbles following collection or storage Occurrence of bubbles in the water collection bottle shall be documented. Informative advisory —If properly collected with no visible air bubbles in the collection bottle, water can often be stored at room temperature for several hours without adverse effects. If the sample warms such that bubbles form in the collection bottle, cooling of the sample will not “redissolve” the gas back into solution. 6.5 Onsite cocktails Note —Cocktails for liquid scintillation measurement may be prepared onsite by transporting scintillation vials containing pre-measured fluid. Preparation onsite eliminates the need for a sample transfer in the laboratory. This method is primarily used for research or laboratory purposes.