Responseto Suspected Intakes

DOE-STD-1136-2004

Guide of Good Practices for Occupational Radiological Protection in Uranium Facilities

When the CEDE for an estimated intake is between 2 rem and 20 rem, treatment should be

considered. Under these situations, short-term administration will usually be appropriate.

When the CEDE equivalent for an estimated intake exceeds 20 rem, then extended or protracted

treatment is strongly recommended, except for poorly transported material in the lung.

A useful method to enhance excretion of uranium via the kidneys is the formation of radionuclide

complexes using sodium bicarbonate. This type of complexation appears to be the only current method

that has a reasonable chance of reducing or preventing kidney damage during the early period after

incorporation of this chemotoxic heavy metal.

An initial prophylactic chelation therapy may be appropriate because bioassay measurements

(particularly urinalysis) cannot usually be completed within the response time required for effective

chelation therapy. Urinalysis becomes very helpful following administration of chelation therapy because

there is a direct correlation between urinary excretion and dose averted because of uranium excreted. This

provides a method of measuring the effectiveness of chelation therapy and determining if it is worthwhile to

continue therapy. It is probably that the efficacy of treatment will decrease with continued administration as

uranium is removed and the rate of transfer into the systemic compartment decreases.

5.10 RESPONSE TO SUSPECTED INTAKES

Experience has shown that most intakes of uranium are accidental. Uranium facilities and operating

procedures are designed to prevent intakes. Nonetheless, it is important for management to prepare for the

possibility that workers might receive an intake of uranium--even though the probability of an incident may

be very small. Prompt and appropriate action following an accidental intake of uranium will allow for

therapeutic measures to be taken to minimize the internal contamination and lessen the potential for harmful

effects. The health physicist and medical staff should work closely to ensure that the proper course of action

is followed.

All employees suspected of having received an intake of uranium should be referred for special

bioassay measurements. Because a fraction of an intake by inhalation may be retained in the nasal passages

for a few hours after exposure to airborne radioactive materials, any level of contamination on a nasal swab

indicates an intake that should be followed up by a special bioassay measurement program. However, lack

of detection on nasal smears cannot be taken as evidence that an intake did not occur either because the

nasal passages can be expected to clear very rapidly or, alternatively, because the worker could be a mouth-

breather. Special bioassay should also be initiated if uranium contamination is found on the worker in the

vicinity of nose or mouth.

Developing specific field criteria to identify the need for medical response can be challenging.

Inhalation intake estimations based on DAC-hours exposure are straightforward and discussed earlier in this

document. Early bioassay measurement levels corresponding to the action levels have been calculated at

Hanford and are summarized in Table 5-17. Another method is to develop field observation criteria (e.g.,

nasal smear or skin contamination criteria) which might imply that an action level has been exceeded. This

latter approach is highly subjective with any number chosen likely to be arguable. Knowledge of facility

operations, material forms, and past experience will likely play a key role in development of such criteria.

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