ARRRG/FOOD, Doses from Radioactive Release to Food Chain

1 - Description of problem or function: ARRRG calculates radiation doses to humans for radionuclides released to bodies of water from which people might obtain fish, other aquatic foods, or drinking water, and in which they might fish, swim, or boat. FOOD calculates radiation doses to humans from deposition on farm or garden soil and crops during either an atmospheric or water release of radionuclides. Deposition may be either directly from the air or from irrigation water. With both programs, doses may be calculated for either a maximum- exposed individual or for a population group. Doses calculated are a one-year dose and a committed dose from one year of exposure. The exposure is usually considered as chronic; however, equations are included to calculate dose and dose commitment from acute, one-time, exposure. 2 - Method of solution: The radiation doses from external exposure to contaminated farm fields or shorelines are calculated assuming an 'infinite' flat plane source of radionuclides. A factor of two is included for surface roughness, and a modifying factor is used to compensate for finite extent in the shoreline calculations. The radionuclide concentrations in aquatic and irrigated food products are based on the radionuclide concentration in the contaminated water, which is based on the release rate of radioactive contamination and the characteristics of the receiving water body. Concentration of radionuclides in plants depends on the concentrations in the soil, air, and water. Concentration of radionuclides in farm animal products, such as milk, meat, or eggs, depends on the animal's consumption of feed, forage, and water containing radionuclides. For persons swimming in contaminated water, the dose is calculated assuming that the body of water is an infinite medium relative to the range of emitted radiations. Persons boating on the water are assumed to be exposed to a dose rate half that of swimmers. Internal doses are calculated as a function of radionuclide concentration in food products, ingestion rates, and a radionuclide-specific factor. The equations for calculating internal dose and dose commitment are derived from those given by the International Commission on Radiological Protection (ICRP) for body burden and maximum permissible concentration (MPC). 3 - Restrictions on the complexity of the problem: Maxima of: 23 possible body organs or tissues (ARRRG and FOOD), 5 organs and 100 radionuclides in a mixture (ARRRG and FOOD), 5 ingestion pathways (ARRRG), 3 external pathways (ARRRG), 14 food type pathways (FOOD), 1 external pathway (FOOD)