233
Time-Dependent Alteration of Uranium Load
The alteration in amount of uranium loaded in various body tissues/organs with
time is encapsulated in Fig. 7. Cortical bone volume and soft tissues do not reach
steady-state equilibrium even after 60 years of uninterrupted uranium exposure. In
contrast, the trabecular bone volume, kidney and liver saturate. The maximum
amount of natural uranium clings to the cortical bone volume at all times.
The log scale plot in Fig. 8 depicts clearly that during early stage, kidneys bear
more uranium load than the liver. However, after 750 days (approx.), the situation
reverses until uranium content saturates in both compartments.
Transfer Coefficients
The transfer coefficient f, also called the rate coefficient, is calculated as the ratio of
uranium content in a particular organ to amount of uranium consumed daily by the
person. In the present case study, transfer coefficients for the kidney, liver, skeleton,
GI tract, soft tissue, urinary bladder and blood have been calculated and compared
with those from previous studies in Table 4.
The value of ‘f’ observed for the GI tract is the same as that obtained by Jakhu
et al. (2016), but that for the urinary bladder shows a tenfold decrease. The transfer
factor is highest for skeleton and least for the urinary bladder, which supports the
trend of calculated uranium retention in the different tissues and organs. The wide
variation in values of ‘f’ for different tissues and organs points to the fact that the
biokinetics of uranium varies from organ to organ.
Fig. 7 Variation of uranium load in different human body compartments with time
Biokinetic Modelling and Risk Assessment of Uranium in Humans
Time-Dependent Alteration of Uranium Load
The alteration in amount of uranium loaded in various body tissues/organs with
time is encapsulated in Fig. 7. Cortical bone volume and soft tissues do not reach
steady-state equilibrium even after 60 years of uninterrupted uranium exposure. In
contrast, the trabecular bone volume, kidney and liver saturate. The maximum
amount of natural uranium clings to the cortical bone volume at all times.
The log scale plot in Fig. 8 depicts clearly that during early stage, kidneys bear
more uranium load than the liver. However, after 750 days (approx.), the situation
reverses until uranium content saturates in both compartments.
Transfer Coefficients
The transfer coefficient f, also called the rate coefficient, is calculated as the ratio of
uranium content in a particular organ to amount of uranium consumed daily by the
person. In the present case study, transfer coefficients for the kidney, liver, skeleton,
GI tract, soft tissue, urinary bladder and blood have been calculated and compared
with those from previous studies in Table 4.
The value of ‘f’ observed for the GI tract is the same as that obtained by Jakhu
et al. (2016), but that for the urinary bladder shows a tenfold decrease. The transfer
factor is highest for skeleton and least for the urinary bladder, which supports the
trend of calculated uranium retention in the different tissues and organs. The wide
variation in values of ‘f’ for different tissues and organs points to the fact that the
biokinetics of uranium varies from organ to organ.
Fig. 7 Variation of uranium load in different human body compartments with time
Biokinetic Modelling and Risk Assessment of Uranium in Humans