238U and 232Th series nuclides in groundwater from the J-13 well at the Nevada Test Site: Implications for ion retardation

The activities of members of the 238U and 232Th decay chains have been determined in water from well J‐13 at the Nevada Test Site near Yucca Mountain. Using 222Rn as a measure of recoil flux, adsorption (k1) and desorption (k2) rate constants for Ra and Pb have been determined. The ratio (k1/k2), defined as the dimensionless distribution coefficient, K, is 1.3 × 104 for Ra and 2.7 × 104 for Pb and is estimated to be about 104 for Th.