title: Parameterization of a dynamic specific activity model of 14C transfer from surface water-to-humans.
abstract: Carbon-14 is a particularly interesting radionuclide from the perspective of dose estimation because it mixes readily with stable CO2, and hence enters the food-chain as fundamental biomolecules. A model was developed for the situation of 14C releases to surface waters, where there are distinct changes in the water 14C activity concentrations throughout the year. The model computes the specific activity in water, phytoplankton, fish, crops, meat, milk and air, following a typical irrigation-based food-chain scenario. This paper describes the derivation of the required 14C-specific parameter values. Many of the key parameters are not commonly measured, at least not in the context of dose assessment. Thus, inference from other sources of data was required, and this is the scientific contribution described in this paper. The best estimates and appropriate measures of statistical dispersion are provided. This required consideration of both the temporal and spatial averaging domains to ensure they were correct for parameters as defined in the model. The model coupled with these parameter values represents several new developments for modelling 14C transfers.
authors.affiliation: ECOMatters Inc., 24 Aberdeen Avenue, Box 430, Pinawa, Manitoba, Canada, R0E 1L0. sheppards@ecomatters.com
authors.forename: S C
authors.initials: SC
authors.lastname: Sheppard
authors.forename: M I
authors.initials: MI
authors.lastname: Sheppard
authors.forename: F
authors.initials: F
authors.lastname: Siclet
mesh_terms: D000398:Air Pollution, Radioactive / Q000009:adverse effects*; D000818:Animals; D002245:Carbon Dioxide / Q000737:chemistry; D002250:Carbon Radioisotopes / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D004784:Environmental Monitoring; D005399:Fishes; D005507:Food Contamination, Radioactive / Q000032:analysis*; D006801:Humans; D008892:Milk / Q000378:metabolism / Q000528:radiation effects; D008954:Models, Biological; D010945:Plants, Edible / Q000378:metabolism / Q000528:radiation effects; D013997:Time Factors; D014878:Water Pollution, Radioactive / Q000009:adverse effects*; D015048:Zooplankton / Q000378:metabolism / Q000528:radiation effects
chemical_list: D002250:Carbon Radioisotopes; D002245:Carbon Dioxide