Intake and Dose Assessment for Soluble OBT

DOE-HDBK-1184-2004

Soluble forms of OBTs are considered to be instantaneously absorbed into the

body, therefore, urinalysis can be used to assess soluble OBT intakes. This

approach is adequate to demonstrate compliance with the dose limits established in

subpart C of 10 CFR 835. To determine the soluble OBT intake, the individual's

average urine excretion volume (if not available, the ICRP 23 Reference Man value

of 1.4 liter per day should be used) and the ICRP 78 expected excretion rate per

unit intake of soluble OBT should be used.

Internal soluble OBT doses should be assessed by either:

1. Using the CEDE DCF listed above for soluble OBT (LuDEP may also be used to

calculate individual organ CDE DCFs); or

2. Using LuDEP to convert the intake amount to final CEDE (LuDEP may also be

used to calculate individual organ CDEs).

NOTE: LuDEP can accommodate injection and ingestion intakes of soluble

materials, as well as inhalations of particulates, and can be used to

document the soluble OBT dose calculations. Using the ICRP 78 biokinetic

model for soluble OBT above, LuDEP calculates 4.2 10-11 Sievert CEDE

per Bequerel intake by injection or ingestion, which is the same as the

ICRP 78 CEDE DCF for soluble OBT intake by ingestion. This value is

slightly larger than the DCF for soluble OBT (based on inhalation) quoted at

the beginning of this section (4.1 10-11 Sv/Bq). Therefore, using LuDEP for

soluble OBT intakes provides a slight overestimate of the CEDE, compared

to that which would be obtained by simply using the DCF listed above.