MAX. PERMISSIBLE CONCENTRATION IN AIR: 0.002 p. Ci/ml (3H2);
0.000005 I~Ci/ml (3H20)
C
ONCERNS
The major concern with using H-3 is that it cannot be easily
monitored during its use, therefore, special precautions are needed to
keep the work environment clean. The regular use of wipe testing is the
only way to insure that your work space is not contaminated.
Contamination on the skin will not likely cause a significant dose to
the dead layer of skin, however, it could lead to the internal
absorption of H-3. The maximum permissible body burden to the whole body
is 1 mCi.
S
HIELDING
Glass and plastic are the best shields for beta particles from H-3.
D
OSIMETRY
Millicurie (37 MBq) quantities of
tritium do not present an external exposure hazard because the
low-energy beta emitted cannot penetrate the outer dead layer of skin.
Exposure to an atmosphere containing
tritiated water results in intake of 3H
by both inhalation and absorption through the intact skin.
Three to four hours after intake,
ingested, inhaled or absorbed tritiated water is uniformly distributed
in all body water.
On average, tritiated water is
eliminated with a 10-day biological half-life. Elimination rates can be
increased by increasing water intake.
O
CCUPATIONAL LIMITS
Annual Limit on Intake(ALI):
80 mCi (3 GBq)
(Ingestion or Inhalation)
Derived Air Concentration (DAC):
2E-5 µCi/mL (740 kBq/m3).
D
ETECTION
A tiny drop of contamination containing H-3 can be
easily detected with a wipe test from a liquid scintillation counter. A
Geiger counter will not detect the presence of H-3.
G
ENERAL HANDLING
PRECAUTIONS FOR TRITIUM
(3H)
Many tritium compounds readily penetrate
gloves and skin. Handle these compounds remotely, wear two pairs of
gloves and change the outer layer at least every 20 minutes. Tritiated
DNA precursors are considered more toxic than tritiated water depending
on their route of intake. However, they are generally less volatile and
do not normally present a significantly greater hazard.
1. Designate areas for handling
3H and clearly label all containers.
2. Prohibit eating, drinking, and smoking in room
where 3H is handled.
3. Use transfer pipettes, spill trays and absorbent
coverings to confine contamination.
4. Handle potentially volatile compounds in
ventilated enclosures.
5. If enhanced containment is necessary, handle
volatile compounds in closed systems vented through suitable traps.
6. Sample exhausted effluent and room air by
continuously drawing a known volume through a membrane filter followed
by an impinger containing water.
7. Wear disposable lab coat, gloves and wrist guards
for secondary protection.
8. Select gloves appropriate for chemicals handled.
9. Maintain control by regular monitoring and prompt
decontamination of gloves and surfaces.
10. Use open-window ionization detector or liquid
scintillation counter to detect 3H.
11. Submit periodic urine samples for bioassay to
determine uptake by personnel.
12. Establish air concentration, surface
contamination, and bioassay action levels below regulatory limits.
Investigate and correct any conditions that may cause these levels to be
exceeded.
13. On completing an operation, secure all
3H; remove and dispose of protective
clothing and coverings; monitor and decontaminate self and surfaces;
wash hands and monitor them again.
E
QUIPMENT/SUPPLIES
The following equipment and supplies must be available:
A liquid scintillation detector
Disposable latex or plastic gloves
Full-length lab coat
Containers for radioactive waste
Pipettes dedicated to the use of H-3
Commercial decontaminate
S
AFETY RULES
If the following safety precautions are used, personnel radiation
exposure will be As Low As Reasonably Achievable.
Designate a specific area of the lab for H-3 handling.
Full-length lab coats must be worn by all persons who
handle Tritium.
Protect the skin of your hands from becoming
contaminated from spills by wearing two pairs of disposable gloves .
Never pipette H-3 by mouth (DUH).
Only use pipettes which have been dedicated to your
specific use of H-3; pipettes will easily become contaminated and
therefore, should not be shared with others .
If you have reason to believe that your gloves are
contaminated, immediately dispose of them in the radioactive waste
container.
P
OST-USE
PROCEDURES
Conduct a wipe test and count the wipes in a Liquid
Scintillation counter.
Check all equipment, centrifuges, water baths for
contamination.
If any contamination is found, use a commercial
radiation contamination remover with paper towels to clean up the
equipment .
Place the towels in the radioactive waste receptacle.
If contamination cannot be removed, place a
"radiation" label on the equipment indicating that it is H-3, maximum
cpm found, and the date you measured the level.
Check the work bench and floor.
If contamination is found, it can usually be removed
easily.
If it cannot be removed, contact the RSO to obtain
shielding materials
Inform your fellow lab workers if any irremovable contamination is
found.
Check the normal trash container to make sure no
radioactive waste has been accidentally placed there.
Store waste temporarily in specially marked
containers.
Wash your hands thoroughly.
TRITIUM 
