Radium geographic distribution

Data on the geographic distribution of surficial radium concentrations were acquired by the National Airborne Radiometric Reconnaissance (NARR) survey, part of the National Uranium Resource Evaluation (NURE) program conducted by the U.S. Department of Energy in the mid-1970s. The data were originally collected and tabulated by 1° by 2° quadrangle map area, and the data cover approximately 450 out of a total of 474 such quadrangles... 

Jaworowski, Z. Temporal and geographical distribution of radium D (lead-210). Nature 212, 886—889 (1966). 

Radium is a naturally-occurring metal and is almost ubiquitous at low concentrations in air, water, soil, rocks, and food. The median concentrations of radium-226 and radium-228 in drinking water are generally low, but there are geographic areas where higher concentrations of radium are known to occur. The utilization of coal and uranium has resulted in re-distributing radium in the environment, but the overall effects appear to be small. Estimated levels of average human exposure to radium of nonoccupational populations are presented in Table 5-1. 

---