title: A review of parameter values used to assess the transport of plutonium, uranium, and thorium in terrestrial food chains.
abstract: A general methodology of predicting the food chain transport of atmospherically deposited radionuclides is reviewed with an emphasis on variation in parameter values important for realistic behavioral characterization of environmental releases of plutonium, uranium, and thorium. Parameters important to generic simulations of food chain transport, given a known constant deposition onto vegetation, include: fractional interception of particulates by vegetation, vegetation density, effective half-life of contamination on vegetation, soil-to-plant transfer factors, consumption rates by cattle and man, and transfer of nuclides from forage to meat and from forage to milk. Variation in these parameters, which has been encountered in field studies, is summarized. A partial reduction in the variation of predicted concentrations of actinides in foods can be accomplished by more accurately determining critical parameter values like fractional interception of deposition by vegetation, vegetation biomass, and the effective half-life of contamination on vegetation. Field research describing the site dependency and time dependency of probability density functions for model parameter values is needed to make probabilistic predictions concerning Pu, U, and Th transport in food chains and to reduce the uncertainty associated with model predictions and generic assessments of environmental impact.
mesh_terms: D001692:Biological Transport; D004784:Environmental Monitoring; D005507:Food Contamination, Radioactive / Q000517:prevention & control*; D011005:Plutonium / Q000493:pharmacokinetics*; D012016:Reference Values; D013910:Thorium / Q000493:pharmacokinetics*; D014501:Uranium / Q000493:pharmacokinetics*
chemical_list: D014501:Uranium; D011005:Plutonium; D013910:Thorium