Investigation Level and Derived Investigation Level

DOE-STD-1121-98

involve special measurements, work history review, determination of material form, and

modification of biokinetic parameters, and may culminate in a dose assessment.

Medical Referral Level, LMR - The level of intake or dose at or above which the medical staff

shall be notified. The notification should be made as promptly as possible, but does not

necessarily constitute an identified need for therapy.

Some suggested numerical values for these levels are shown in Table II. Additional discussion

about the investigation level and derived investigation levels is provided in the following sections. This

discussion is warranted by the definition of a 100-mrem investigation level in the IDG.

4.3 INVESTIGATION LEVEL AND DERIVED INVESTIGATION LEVEL

In the IDG, the investigation level is an HE,50 of 0.1 rem (0.001 Sv) from intakes occurring in a year

for general employees. Special ILs for minors, visitors, and the embryo/fetus of a declared pregnant

worker should not exceed 50 mrem (0.5 mSv). Throughout this document, IL refers to the IL for the

appropriate group unless otherwise specified.

In cases where it is practical, feasible, and affordable, internal dose evaluation programs should have

a goal of assessing intakes of radioactive materials that occur in a year and that deliver a committed

effective dose equivalent at the IL, that is, intakes of 0.02 stochastic annual limit on intake (SALI) for

general employees and 0.01 SALI (or less) for declared pregnant workers, minors, and visitors.

With the exception of the IL, which is specified in the IDG on the basis of monitoring thresholds in

10 CFR 835.402, DOE sites are encouraged to consider using the alternative reference level quantities

given in Table II.

Table II. Example Reference Level Magnitudes

General Employee, Except

Minor, Visitor, Declared

Declared Pregnant Worker

Pregnant Worker

Reference Levels

Intake

Corresponding

(Amounts of Intake, Except for DOE

Intake

Corresponding

HE,50 (rem)1

HE,50 (rem)

(SALI)

IL)

(SALI)

Verification Level, LV

0.02

0.1

0.005

0.025

DOE Investigation Level, IL

0.02

0.1

0.01

0.05

[Alternative Investigation Level]

[0.1]

[0.5]

Medical Referral Level, LMR

Note that in the case of a declared pregnant worker, the dose to the embryo/fetus is the dose to be

considered, not the dose to the worker.

4.4 DERIVED INVESTIGATION LEVELS

Derived investigation levels (DILs) are derived reference levels of routine individual monitoring

results. Examples of DILs are bioassay results, such as organ or body contents, or excreta concentrations

or excretion rates, that indicate an intake resulting in a dose exceeding an IL. Other examples of DILs are