The bioconcentration of 131I in fresh water fish

The dynamic characteristics of the radionuclide concentration process in fresh water fish have been studied. The experimental data for the tilapias were fitted using a simple compartment model to get characteristic parameters such as concentration factors, elimination rate constants, and initial concentration rates, which are 3.08 Bq kg-1/Bq L-1, 0.00573 h-1, and 12.42 Bq kg-1 h-1, respectively. The relative concentrations of 131I in different parts, i.e., head, gills, flesh, bone and internal organs, of the tilapias are also determined, which are found to be 10.8, 15.4, 26.1, 11.0, and 37.0%, respectively. The effects of different factors on the transfer of radionuclides in fresh water fishes are also discussed. Experiments on the tilapias and the common carp show that the variation of concentration factors for different species may be significant even for the same radionuclide and the same ecological system. On the other hand, the variation in the concentration factors for the flesh of the tilapias is not significant for a certain range of 131I concentrations in the water.