Computer Modelling of the Chemical Speciation of Lanthanide and Actinide Elements in the Human Gastrointestinal Tract: Mouth and Stomach

JESS 53 computer modelling was used to produce biokinetic models of the gastrointestinal tract in order for the radiation dose from internally deposited radionuclides to be calculated. Preliminary estimations of the interactions of Eu and Am with all the metal binding species present in the mouth and stomach, i.e. saliva over a pH range of 5.6-7.6, and gastric juice over a pH range of 1.5-5.5, and at a temperature of 37°C, have been made. The development of the models, and initial validation results for the use of Eu as a surrogate for Am, are presented and discussed. From these aqueous studies it appears that the use of Eu as a surrogate for Am in saliva or gastric juice is doubtful. However, further speciation modelling, incorporating solids, is in process to confirm these findings.