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Title: Modeled concentrations in rice and ingestion doses from chronic atmospheric releases of tritium

Abstract

The expansion of nuclear power programs in Asia has stimulated interest in the improved modeling of concentrations of tritium in rice, a staple crop grown throughout the far east. Normally, the specific activity model is used to calculate concentrations of tritium in the tissue water of edible plants to assess ingestion dose from chronic releases. However, because rice, like other grains, has much lower water content than most crops, the calculation must also account for organically bound tritium. This paper reviews ways to calculate steady-state concentrations of tritium in rice, including the methods of Canadian and US regulatory models, and the assumptions behind them. Concentrations in rice and resulting ingestion doses are compared for the various methods, and equations for calculating concentrations are recommended. The regulatory models underestimate doses received from ingestion of rice contaminated with tritium since they do not account explicitly for organically bound tritium. The importance of including organically bound tritium is illustrated in a comparison of doses from rice, leafy vegetables and milk for an Asian diet. Dose factors from tritium for these foods are estimated to be 135, 47, and 20 nSv y{sup {minus}1}/(Bq m{sup {minus}3}), respectively. Assuming known air concentrations, tritium concentrations in rice,more » calculated with the recommended equations, are uncertain by less than a factor 2 when tritium concentrations in the rice paddy water are known, and by less than a factor of 2.3 when concentrations in paddy water are unknown.« less

Authors:
;
Publication Date:
Research Org.:
Chalk River Labs., Ontario (CA)
OSTI Identifier:
20075782
Resource Type:
Journal Article
Journal Name:
Health Physics
Additional Journal Information:
Journal Volume: 78; Journal Issue: 5; Other Information: PBD: May 2000; Journal ID: ISSN 0017-9078
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; AIR POLLUTION; RADIATION MONITORING; TRITIUM; RADIATION DOSES; INGESTION; MATHEMATICAL MODELS; RICE; FOOD CHAINS; CONTAMINATION

Citation Formats

Peterson, S.R., and Davis, P.A. Modeled concentrations in rice and ingestion doses from chronic atmospheric releases of tritium. United States: N. p., 2000. Web. doi:10.1097/00004032-200005000-00011.
Peterson, S.R., & Davis, P.A. Modeled concentrations in rice and ingestion doses from chronic atmospheric releases of tritium. United States. doi:10.1097/00004032-200005000-00011.
Peterson, S.R., and Davis, P.A. Mon . "Modeled concentrations in rice and ingestion doses from chronic atmospheric releases of tritium". United States. doi:10.1097/00004032-200005000-00011.
@article{osti_20075782,
title = {Modeled concentrations in rice and ingestion doses from chronic atmospheric releases of tritium},
author = {Peterson, S.R. and Davis, P.A.},
abstractNote = {The expansion of nuclear power programs in Asia has stimulated interest in the improved modeling of concentrations of tritium in rice, a staple crop grown throughout the far east. Normally, the specific activity model is used to calculate concentrations of tritium in the tissue water of edible plants to assess ingestion dose from chronic releases. However, because rice, like other grains, has much lower water content than most crops, the calculation must also account for organically bound tritium. This paper reviews ways to calculate steady-state concentrations of tritium in rice, including the methods of Canadian and US regulatory models, and the assumptions behind them. Concentrations in rice and resulting ingestion doses are compared for the various methods, and equations for calculating concentrations are recommended. The regulatory models underestimate doses received from ingestion of rice contaminated with tritium since they do not account explicitly for organically bound tritium. The importance of including organically bound tritium is illustrated in a comparison of doses from rice, leafy vegetables and milk for an Asian diet. Dose factors from tritium for these foods are estimated to be 135, 47, and 20 nSv y{sup {minus}1}/(Bq m{sup {minus}3}), respectively. Assuming known air concentrations, tritium concentrations in rice, calculated with the recommended equations, are uncertain by less than a factor 2 when tritium concentrations in the rice paddy water are known, and by less than a factor of 2.3 when concentrations in paddy water are unknown.},
doi = {10.1097/00004032-200005000-00011},
journal = {Health Physics},
issn = {0017-9078},
number = 5,
volume = 78,
place = {United States},
year = {2000},
month = {5}
}