Evaluation of Gross Alpha and Uranium Measurements for MCL Compliance

OBJECTIVES: The objectives of this project were to determine and quantify the source of bias and error that affect the gross alphaparticle activity (GAA) and the uranium concentration of drinking water samples; determine conditions under which the GAA and the uranium concentration can exceed their true values and cause false-positive violations; provide guidance to water utility, regulatory, and laboratory personnel on how to identify the source of a GAA violation and on how to identify and respond to a false-positive violation; and suggest ways of modifying some of the current radiological methods to improve inter-laboratory consistency.