Abstract
The concentration of radon in tap water supplies varied from 47 nCi/1 to 370 nCi/1. Indoor air concentrations varied from <0.5 pCi/1 to 19.1 pCi/1 and 0.001 WL to 0.025 WL for radon and radon daughters, respectively. The transfer of radon from tap water raised the radon concentration in the bathroom air during operation of the shower. Transfer efficiencies of 37% to 70% were observed.
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