The atmospheric dispersion model (Tritium-EESAD) was further modified so as to be able to predict tritium concentration in plant tissue free water (TFWT), organically-bound tritium (OBT) and groundwater. The modified model was validated by participating in the Pine Tree Scenario of the IAEA EMRAS program. Monitoring data were disclosed after submission of model predictions and compared with them. Overall time trends of the predicted tritium concentrations in almost all calculation endpoints agreed well with those of observations within a factor of two.