activity concentrations were observed to increase rapidly and to decline slowly throughout the residence time of persons at Rongelap and Utirik Atolls (Co75, Le80b). These observations led to the selection of a declining continuous intake model. An exponential decline in the amount of activity ingested each day from The following general equations were derived the dietary sources was assumed. (Le80b). They may be applied to each nuclide of concern: uv hP® = S$, _ Xk, Loi fy (zr. k,-k 0° ' , e -(A+k)t or Ape 1 ” fy fz, ~Chtky)t e ~(Atk; )t )) =CA\tks)t a7 4° (ixie Kip eink (2) Chee | e OHKG Ey)” (e \) where t = time post onset of intake (time from day of return of each atoll population), d, A = instantaneous fraction of atoms decaying per unit time, d Pp° = initial daily atom ingestion rate on day of return, atoms s , , k = instantaneous fraction of atoms removed from compartment i in the body by biological processes, at, X = compartment i deposition fraction,