Protocol for the Collection, Transfer and ANSI/AARST MW-RN 2020 Measurement of Radon in Water 14 5.6 Collection Method 2—Syringe Method This collection method applies for laboratory methods that require creating what is known as a “ cocktail ” by mixing a specific volume of sampled water with a scintillation fluid. The following procedure pertains to extracting 10 mL of water. If a laboratory uses a different volume, the procedure shall be adjusted accordingly. Clear tubing shall be used so the collector can visually confirm that there are no air pockets or bubbles in the tubing. Informative advisory —When air is observed in the tubing, one can typically pinch the tubing near the air pocket to release the trapped air prior to sample collection. Note—Proper methods to collect water for a radon measurement have been published. A procedure for sampling potable water from a faucet 4 is frequently used to produce liquid scintillation cocktails , and not for filling of bottles for a laboratory. 5.6.1 Upright funnel—Syringe method Immediately after a thorough flushing of the water system in accordance with Section 4 , the following Steps 1-10 are required: (1) Remove all aeration and filter devices from the faucet where the sample will be taken. (2) Attach a sampling funnel (9” or 23 cmmax. diam.) and clear tubing ( ½ ” or 1.25 cmmax. diam. and 24” or 60 cmmax. leng th ) to the faucet. (3) Turn on the water and allow a steady flow for several minutes. Remove all bubbles in the tubing. Figure 5.6.1 Upright Funnel U.S. EPA recommended collection method that utilizes an inverted funnel and a syringe to extract the sample for injection into a liquid scintillation cocktail . (4) Slow the water flow and hold the funnel open end up. Adjust the flow such that the water entering the bottom of the funnel is not turbulent but overflows the funnel. 4 U.S. Environmental Protection Agency (1978). Radon in Water Sampling Program, Eastern Environmental Radiation Facility, EPA/EERF-Manual-78-1.