ABSTRACT
The occurrence of natural radionuclides in drinking water has been the subject of extensive study since 1976, when the U.S. Environmental Protection Agency (U.S. EPA) established drinking water standards for gross alpha and radium (Ra). Most of these studies have focused on "hot spots" of 226Ra and/ or 228Ra found during the first round of compliance monitoring by the states. Thus, by 1980, there was an initial indication of where 226Ra was elevated and some understanding of the factors that contributed to Ra distribution.
