Environmental behaviour of radioactive particles: Transfer to animals.

Field data on behaviour of artificial polydisperse radioactive silica particles in the components of the cattle food chain are presented. The model fused radioactive particles reproduced the spherical shape of particles in the local deposition during nuclear tests, including their specific gravity and polydispersity. It is shown that the composition of radioactive particles entering the body of animals differs from those initially deposited on the surface of pasture grass. The intake of particles into the body of animals decreased with increasing particle size. The intake for particles of 400-800 µm was about 10 times lower than that for fine particles sized 0-100 µm. It was found that the excretion rate of radioactive particles from the animal body also depends on particle size. The deposition of radioactive particles on the fundal surface of the wall of the ventral rumen sac and reticulum, as well as the long-term retention of radioactive particles of all sizes in the abomasum was noted. This can result in substantial damage in the GIT system, in particular, in these parts of the cattle digestive tract the focal ulcerative lesions of the mucous membrane can be formed by « hot ¼ radioactive particles.

[The Patterns of Behavior of Radioactive Particles in the Food Chain of Cattle and Transport in the Gastrointestinal Tract of Animals].

The analysis of the patterns of behavior of polydisperse radioactive silicate particles in the components of the food chain of cattle is presented. It is shown that the composition of the size distribution of radioactive particles taken into animal organisms differs from the original composition of the particles deposited on the surface of pasture vegetation, and from dispersion of the particles in the aboveground biomass of vegetation at the time of grazing. The intake of particles into animal organisms is reduced with the increase of their size, and for the particle fraction of 400-800 microns it is about 10 times less than for the fine fraction (< 100 microns). The mathematical compartment model ofthe transport of polydisperse radioactive particles in the digestive tract of cattle has been developed. It is found that the elimination rate of radioactive particles from the animal organism depends on their sizes. Deposition of particles on the fundic surface of the wall ventral sac of rumen and reticulum as well as their long stay in comparison with the chyme in abomasum was noted. The maximum levels of irradiation are formed in these parts of the digestive tract of cattle.