Radon-in-Water Sampling Problems

Numerous past studies of waterborne radon sampling and measurement techniques have concluded that today's most frequently used sample collection methods are cumbersome and/or require highly trained and careful technicians. All are prone to error if there is the slightest deviation from the prescribed procedure. Obtaining reasonable accuracy and precision requires a high skill level on the part of the individual collecting the water sample, a skill level that is impossible to expect from persons who are likely to perform sample collections very infrequently. This paper summarizes the studies conducted by Vitz (1991), Burkhart, Gray and Martin (1991), and Hightower and Watson (1995) that show where most of the problems lie. It will also describe a new and proprietary sampling technique developed by the staff at Air Chek, Inc. (hereafter referred to as Air Chek) which is designed to eliminate most if not all of the sample collection problems. The problems of water sample transfer at the laboratory, as pointed out in the above-mentioned studies and revealed by our in-house studies, have also been solved by the Air Chek staff but will not be detailed here because of the highly proprietary nature of the method. The latest release of the U.S. EPA radon-in-water MCL and AMCL is likely to bring many newcomers into the water testing industry. The impending final adoption of these Federal standards intensifies the need to incorporate better sampling techniques and standardized sample collection protocols, and to lay out a set of minimum guidelines which a measurement service must be able to meet in order to ensure that high-quality measurements are the ultimate result.