Tritium

There are 6 isotopes of hydrogen /tritium/. Hydrogen-1 and hydrogen-2 are naturally occurring and stable. Hydrogen-3 is naturally occurring and radioactive. Hydrogen isotopes with mass numbers 4-6 are artificially produced and are radioactive.

Hydrogen-3 /tritium/ half-life: 12.33 years

DECAY PATHWAY: Hydrogen-3, half-life 12.32 years, decays via beta(-) emission (18.590 keV) to helium-3, half-life stable

Half-life: 12.26 yr; decay constant: 1.765X10-9/sec; maximum beta energy: 18.6 keV; mean beta energy, 5.7 keV; maximum specific activity: 1078.9 GBq/mmol; molar activiity: 2157 TBq/mol

For more Other Experimental Properties (Complete) data for TRITIUM, RADIOACTIVE (12 total), please visit the HSDB record page.

Source: Cosmic rays interacting with air molecules; Nuclear fission with a yield of about 0.01%; Neutron absorption of lithium-6 atoms; [Argonne] Half-Life: 12 years Effective Half-Life: 12 days Specific Activity: 9,800 Ci/gm Decay Mode: Beta GI Absorption: Completely absorbed; Critical Organ: Total body Internal Toxicity: Low Annual Limit on Intake: 80 mCi Radiation Energy (MeV): Beta 0.0186 (100%) Radiation Accidents: 2 accidents with 7 people exposed and 2 deaths; [See Glossary for references.] See Hydrogen. See Radiation, ionizing.

USDOE; Primer on Tritium Safe Handling Practices DOE-HDBK-1079-94 (December 1994). Available from: http://www.eh.doe.gov/techstds/standard/hdbk1079/hdbk1079.pdf as of July 27, 2006.

Pacific Northwest National Laboratory; HANFORD: Radiation and Health Technology Methods and Models of the Hanford Internal Dosimetry Program. PNNL-MA-860 (2003) Available at http://www.pnl.gov/eshs/pub/pnnl860/pnnl860.pdf as of October 4, 2006

Multi-Agency Radiological Laboratory Analytical Protocols Manual Volume II: Chapters 10-17 and Appendix F. (July 2004) NUREG-1576, EPA 402-B-04-001B, NTIS PB2004-105421. Available at http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1576/sr1576v2.pdf as of October 12, 2006

Under the implementing regulations of the Resource Conservation and Recovery Act (RCRA) [specifically at 40 CFR 261.4(a)(4)], source, special nuclear and by-product material as defined by the Atomic Energy Act of 1954 (AEA) is excluded from the definition of solid waste (and thus, from the RCRA hazardous waste management requirements). ... Accelerator-produced tritium, on the other hand, does not qualify for this exclusion (since the tritium is produced by a linear accelerator, and does not involve the production or utilization of special nuclear materials or the extraction or concentration of source material). ... Pursuant to the RCRA regulations, it is the responsibility of the generator of a waste to determine if that waste is subject to the hazardous waste requirements [40 CFR 262.11].

Hydrogen-3

Radioactive material

Atomic number: 1；Reportable quantity: 100 (3.7) [Curie(Terabecquerels)]

Tritium has a high coefficient of diffusion. It readily diffuses through porous substances such as rubber and can also diffuse through metals. As tritium decays in a container of constant volume at a constant temperature, the tritium partial pressure decreases and the partial pressure of 3He increases. The pressure in the container approaches twice that of the original container pressure.

Plain carbon steels and alloy steels must not be used for tritium service. These steels have high strength and (normally) a body-centered-cubic crystal structure, both of which make the material less ductile and much more susceptible to hydrogen embrittlement. Ferritic stainless steels (such as Type 430), martensitic stainless steels (both quench-and-tempered (such as Type 410) and precipitation hardening (such as 17-4 PH and PH 13-8 MO)) and precipitation hardened austenitic stainless steels (such as AM-350) should not be used for general tritium service; they are all more susceptible to hydrogen embrittlement than the austenitic stainless steels. Additionally, freemachining grades of austenitic stainless steel (such as Type 303) should not be used.

Other materials that must not be used for tritium service are any material that forms hydride near room temperature and atmospheric pressure. Examples include zirconium, tantalum, niobium, and many alloys of these materials.

All polymers degrade when exposed to radiation. Both tritium and tritiated water permeate all polymers, and permeated tritium deposits the beta decay energy throughout the polymer bulk. (Although the tritium beta energy is very low and has a small penetration depth in matter, permeation allows tritium atoms to be near enough to polymer chains throughout the bulk to cause changes in the polymer by radiation.) Types of radiation-induced changes in polymer properties include either softening (degradation) or hardening, ductility loss, color change, dimensional change, and gas evolution. Because of these effects, polymers should only be used in tritium systems where no metal alternatives exist.

Low-Density polyethylene (LDPE) is very permeable by tritium and tritiated water and should not be considered for use in tritium systems. Polytetrafluoroethylene (PTFE ...) degrades and decomposes in tritium, thus resulting in HF. In humid air, hydrochloric and hydrofluoric acid is then formed, which is highly corrosive. Generally, chlorofluorocarbon polymers should not be used in tritium service. Polyvinyl chloride (PVC) and vinylidene chloride ... are among several polymers used in tritium protective clothing, but should not be used for process equipment because they contain chlorine.

Kel-F is a common chlorofluorocarbon polymer and is incompatible with tritium. It, like PTFE, degrades in tritium gas and should not be used.

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 100 Ci or 3.7x10+12 Bq. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b).

(AL) ALABAMA 20000 pCi/l

(CA) CALIFORNIA 20000 pCi/l

(CT) CONNECTICUT 20,000 pCi/l

(IL) ILLINOIS 20,000 pCi/l

For more State Drinking Water Standards (Complete) data for TRITIUM, RADIOACTIVE (6 total), please visit the HSDB record page.

Leak testing (normally employing a sniff test method) is required for radioactive materials shipments in Type B packages. The package must be leak-tight ... as defined by American National Standards Institute (ANSI) N14.5. ...

/For work with tritium convered under DOE requirements/ Once an item has met the DOE and U.S. Department of Transportation (DOT) requirements for shipment (properly packaged, radioactively surveyed, properly marked, properly filled out shipping papers, etc.) then the item inside the approved shipping package can be shipped to a new location. During shipment, the item inside the approved shipping package is expected to be subject to the normal activities associated with its movement from one location to another; for example, loading and unloading the package from vehicles, transport to a shipping area, storage in the shipping area prior to transport, loading and unloading the package onto trucks/trains/airplanes, and storage in the receiving area after arrival at the new destination. The packaging required by DOT/NRC regulations is designed to protect the workers, the public, and the environment from the radioactive material during normal package handling, transport, and shipping/receiving storage. ... Limited quantities of tritium can be packaged and shipped in strong, tight containers (paper boxes, paint cans) with proper markings. Type A Quantity (21.6 to < 1080 Ci): Type A quantities of tritium use DOT Specification 7A containers, properly marked and surveyed prior to shipment. A number of different packages are available from small cans, 55 and 85 gallon drums, 4 x 4 x 7-foot steel boxes, up to and including oversized, specially designed containers. These containers are relatively inexpensive. Type B Quantity (> 1080 Ci): Type B quantities of tritium must be shipped in a certified DOT Type B package. There is only a limited number of these expensive Type B packages available for tritium shipment (e.g., UC-609), and special routing (i.e., prescribed routes employing highway route control such as using major highways, bypassing cities, etc.) is required.

Gaseous tritium at or near atmospheric pressure occupies 22.414 L/mole at 0 °C, and approximately 24.2 L/mole at room temperature, and requires approved packages for shipment in either Type A or B quantities. If the containers are not properly designed or if they are damaged, the gas can leak from the container into the environment.

Pursuant to the Atomic Energy Act, discharges and releases of tritium to waters from DOE facilities are regulated by DOE and those from licensed nuclear facilities are regulated by NRC or NRC Agreement States. Under the Safe Drinking Water Act, the Environmental Protection Agency (EPA) has established the standard for tritium in water from drinking water systems. EPA and States also use this standard for protection of ground water that may be used as drinking water. DOE requirements prohibit DOE operations from releasing effluents that would cause a drinking water system to exceed this standard.

Gaseous tritium at high pressure takes up less space but is more difficult to contain in part due to the potential for tritium and helium embrittlement of the vessel materials. This embrittlement increases the probability of a tritium leak or catastrophic container failure. Unloading high pressure gas requires specifically designed systems and experienced, skilled operators.

Metal tritides reduce the overall volume of the stored tritium, but some of the finely divided metals used are pyrophoric. Some metals form low melting point alloys with the materials used in the construction of the metal tritide containers. Others require extremely high temperatures in order to recover tritium from the material.

Tritium in the form of T2O may be difficult to store for long periods due to its corrosive properties. Experiments with T2O indicate that pure T2O is corrosive. This corrosiveness is likely due to tritium oxide generating free radicals (OH-) from radiolytic decomposition of water in addition to extra energy from beta decay impinging on surrounding molecules. Additionally, pure T2O, like distilled H2O, will dissolve many materials.

Large quantities of tritium (3-H /in the laboratory/ should be stored in double containers. The inner container holding the labeled material should be in a larger, tightly covered outer container that contains absorbent material, such as kitty litter or cotton balls. ... Long term storage of aqueous material may be done in freezers if no damage to the labeled material will ensue. Storage of double containers in fume hoods is also acceptable. When such materials are stored in refrigerators or freezers, it is normal for condensation and frost to become contaminated. These should be checked by smears of condensation or collection of frost with counting in a liquid scintillation counter.

Following a tritium spill involving a liquid with high specific activity, the area may have to be isolated and other protective measures taken before cleaning up the liquid. Monitoring for possible airborne tritium must be started to determine the need for respiratory protection or skin protection. After the spill has been cleaned up, residual contamination will remain. Depending on the level of contamination, any further steps needed to prevent the spread of contamination and reduce the level to an acceptable value should be determined. Following a release of tritium gas, surfaces would not be expected to be heavily contaminated. If tritiated water vapor is released, the contamination may be greater, depending on the amount and activity of the released vapor. In any case, smear and air surveys will be used to determine the course of action needed to control and reduce the contamination safely.

/For small spills/ Absorb liquids onto kitty litter, then transfer to metal cans. /From table/

The common method of solidification of tritium-contaminated wastewater for disposal is to solidify the water on clay so that it can be classified as solid waste. Clay will hold approximately 60 percent water by volume. Waste disposal sites generally require the use of 100 percent more clay than required to solidify the water, and, as a result, the water is generally limited to 30 percent of the volume of the clay for waste solidification purposes. Water absorbed on clay is not corrosive and may be stored for long periods without damage to the container wall.

Disposable beakers, pipettes, and tools should be placed in plastic bags that are tied or taped closed for disposal into normal radioactive waste. Ensuring a complete bagging of radioactive waste will minimize tritium vapors in the waste storage containers.

Gas (T2): Waste disposal sites generally will not accept packages containing pressurized gases or those in which a potential exists for generating 1.5 atmospheres (absolute) of pressure over time.

Glove boxes should be used for millicurie quantities of volatile cmpd or for 25 mCi or more of tritiated water. Fume hoods or dry boxes should be used for volatile cmpd or when 100 mCi or more is used at one time in volatile form. /From table/

Work with curie levels of tritium should be done in a glove bag or dry box ... inside a fume hood or connected to it. ... Outlet air should pass through a prefilter, then a suitable tritium trap, such as a water bubbler. ... Drip trays are a must. Absorbent paper should be used to line trays and hoods.

Hoods should operate at 125-150 ft/min face velocity. Wherever possible, dry boxes should have separate exhaust blowers that exit directly into the fume hood duct. The flow rate of the hood should be adequate to ensure that thetritium concentration exiting the hood stack is below 2X10-7 uCi/ml.

Disposable labware is recommended.

For more Preventive Measures (Complete) data for TRITIUM, RADIOACTIVE (17 total), please visit the HSDB record page.

Hydrogen-1 half-life: >28X10+23 years

Hydrogen-3 half-life: 12.33 years

Tritium is a beta emitter. It decays to 3He by emitting a beta particle (electron) and a anti-neutrino from one of the neutrons in the nucleus. The energy of the beta particle varies from 0 to 18.6 kiloelectron- volts (keV) with an average energy of 5.69 keV. For scientific purposes, the generally accepted value for the half-life of tritium, as measured by Mound Laboratories, is 12.323+/-0.004 years (4500.88+/-1.46 days).

The Derived Air Concentration (DAC) for tritium is the airborne concentration that, if inhaled over a one-year period, would produce approximately a 5-rem dose to the average worker. The DAC is derived by the formula: DAC = ALI/2400 where DAC = derived air concentration (uCi/cu m3), ALI = annual limit of intake (uCi), 2400 = breathing volume for the average worker over 1 year in cu m= 0.02 cu m/min x 60 min/hr x 40 hr/wk x 50 wk/yr. The DACs for elemental tritium and tritiated water are: HT 5E-01 uCi/mL or 2E10 Bq/ cu m and HTO 2E-05 uCi/mL or 8E05 Bq/cu m, respectively.Recent work in the area of special tritium compound (STC) defined as any compound, except for H2O, that contains tritium, either intentionally (e.g., by synthesis) or inadvertently (e.g. by contamination mechanisms), has been undertaken. These compounds may exhibit unique properties when ingested, absorbed, or inhaled into the human body.

In general, only supplied-air respirators are effective in preventing inhalation of airborne tritium. Two types of air-supplied respirators are available: self-contained breathing apparatus (SCBA) and full-face supplied air masks.

Experience at tritium laboratories has shown that many tritium exposures to personnel occur as a result of contact with highly contaminated surfaces. ...Lab coats and coveralls (fabric barriers) are worn in most tritium facilities. Lab coats are routinely worn to protect personal clothing. Coveralls are sometimes worn for added protection instead of a lab coat when the work is unusually dusty, dirty, or greasy. The protection afforded by lab coats and coveralls is minimal (except for short exposures) when tritium is airborne, but they are more effective in preventing skin contact with contaminated surfaces. Disposable water-proof and water-resistant lab coats and coveralls have been tested at various laboratories. They are not popular for everyday use because of the cost and excessive discomfort inflicted on the worker.

Shoe covers can offer both a degree of personnel protection and control over the spread of contamination on floors. However, in modern facilities where tritium is largely controlled by the use of secondary containment, shoe covers may not be required. Such facilities can easily maintain a clean laboratory environment by the use of regular smear surveys and good housekeeping. Using liquid-proof shoe covers until spills are cleaned up should be considered following spills of tritium-contaminated liquids and solids to prevent the spread of local contamination.

The proper use and selection of gloves are essential. Many factors should be considered in selecting the proper type of glove. These include chemical compatibility, permeation resistance, abrasion resistance, solvent resistance, glove thickness, glove toughness, glove color, shelf life, and unit cost. Gloves are commercially available in butyl rubber, neoprene, polyvinyl chloride (PVC) plastics, latex, etc. The most common gloves found in tritium laboratories are the light-weight, disposable short glove (usually PVC or latex) used for handling lightly contaminated equipment. Depending on the level of contamination, such gloves may be changed frequently (every 10-20 minutes), a second pair may be worn, or heavier gloves may be used instead. When using gloves for this purpose, the work should be planned so that contaminated gloves doe not spread contamination to surfaces that are being kept free of contamination. When working in a glove box using the box gloves, disposable gloves are worn to prevent uptake of HTO contaminating the outside of the box gloves. Again, depending on the level of contamination, more than one additional pair may be required, one of which may be a longer, surgeon's length, glove.

Maximum contaminant levels for radionuclides. ... MCL for beta particle and photon radioactivity. ... The average annual concentration of beta particle and photon radioactivity from man-made radionuclides in drinking water must not produce an annual dose equivalent to the total body or any internal organ greater than 4 millirem/year (mrem/year).

For humans, the estimated maximum permissible total body burden of tritium is 37 MBq (1 mCi)(1).

International Commission on Radiological Protection: MPC (maximum permissible concn), 185 kBq/ml (5 uCi/ml) in breathing air (continuous exposure for 40 hr/wk); maximum permitted body burden, 37 MBq (1 mCi).

Tritium was detected in 4% of 200 portions of foods (raw vegetables, fruits, fish, and milk) collected near 33 nuclear reactors from October 1986 to September 1992(1). The maximum concentration observed in these positive detections was 70 Bq/kg, and most of the positive detections occurred in fish and vegetables in the vicinity of 4 sites(1).

Tritium is an isotope of hydrogen, which allows it to readily bind to hydroxyl radicals, forming tritiated water (HTO), and to carbon atoms. Since tritium is a low energy beta emitter, it is not dangerous externally (its beta particles are unable to penetrate the skin), but it is a radiation hazard when inhaled, ingested via food or water, or absorbed through the skin. Beta particles are able to penetrate living matter to a certain extent and can change the structure of struck molecules. In most cases, such change can be considered to be damage, with results possibly as severe as cancer or death. If the struck molecule is DNA, it can cause spontaneous mutation. (Wikipedia)

/AQUATIC SPECIES/ Using an integrated approach linking different levels of biological organization, the genotoxic, cytotoxic, developmental and survival impact of tritiated water (HTO) were investigated in the embryo-larvae of marine mollusc Mytilus edulis. One-hour-old embryos were exposed to a range of concentrations (0.37-370 kBq/mL) of HTO, which delivered a dose between 0.02 and 21.41 mGy over the exposure period for different end points. Detrimental effects, if any, were monitored at different levels of biological organisation (i.e. DNA, chromosomal, cellular and individual). Genotoxic effects were assessed using molecular and cytogenetic approaches which included analysis of random amplified polymorphic DNA (RAPD), induction of sister chromatid exchanges (SCEs) and chromosomal aberrations (Cabs). Cytotoxic effects were evaluated by determining the proliferative rate index (PRI) of the embryo-larval cells. Developmental and survival effects were also monitored every 24 hr up to 72 hr. Results in general indicated that HTO significantly increased cytogenetic damage, cytotoxicity, developmental abnormalities and mortality of the embryo-larvae as a function of concentration or radiation dose. The analysis of RAPD profiles also revealed qualitative effects in the HTO exposed population compared to controls. However, while the embryo-larvae showed dose or concentration dependent effects for mortality, developmental abnormalities and induction of SCEs, the dose-dependent effects were not apparent for Cabs and PRI at higher doses.

/AQUATIC SPECIES/ In this study, ...the genotoxic effects and tissue-specific concentration of tritium (added as tritiated water, HTO) in the adult life stage of the edible mussel, Mytilus edulis /were evaluated/. The genotoxic effects were quantified in terms of the induction of: (a) micronuclei (MN), and (b) DNA single-strand breaks/alkali-labile sites using alkaline single-cell gel electrophoresis (Comet assay) in the hemocytes of exposed animals. The assays were optimised and validated using a range of concentrations (18-56 mg/L) of ethylmethane sulfonate (EMS), a direct-acting reference genotoxic agent, over different exposure periods. Mussels were exposed to a series of concentrations of HTO equivalent to a dose range from 12 to 485 muGy/hr for 96 hr, and different tissues and organs were then extracted and analysed. The study revealed a dose-dependent increase in the response for both the MN test and the Comet assay and for both EMS and HTO. In addition, HTO delivering dose rates below 500 muGy/hr was shown to be capable of inducing genetic damage in the hemocytes of these bivalves. The study also showed that inorganic tritium accumulated differentially in mussel tissues in a dose-dependent manner, with the gut accumulating the highest amount of radioactivity, followed by the gill, mantle, muscle, foot and byssus thread. The feces and pseudo-feces accumulated least radioactivity over the exposure period.

/AQUATIC SPECIES/ Barnacle embryos were reared in millipore cytology monitors containing approximate tritiated water (HTO) concentrations of background plus 0, 10-5, 10-4, 10-3, 10-2, 10-1, and 100 uCi/mL. After 32 days the cultures were fixed and the numbers of larvae counted. A "molting index," the percentage of larvae that molted at least once, was used to evaluate the effects of HTO on normal development. Effects were observed at concentrations as low as 7x10-6 uCi/mL, and were exponentially related to HTO concentration.

/AQUATIC SPECIES/ Permanence of suppression of the primary immune response in rainbow trout, /Oncorhynchus mykiss/, sublethally exposed to tritiated water during embryogenesis /was studied/. /Doses tested were 0.04, 0.4, 4, and 40 rads/. /After 10 weeks,/ at levels in the range of the maximum possible concentration, tritium produced measureable, dose dependent, and irreversible suppression of immune capacity in affected fish.

For more Ecotoxicity Excerpts (Complete) data for TRITIUM, RADIOACTIVE (9 total), please visit the HSDB record page.

The World Health Organization has estimated the total amount of tritium released from atmospheric testing of nuclear weapons through 1980 was approximately 1.2X10+20 to 2.4X10+20 Bq(1). The total environmental discharge of tritium in the effluent of pressurized water reactor (PWR), boiling water reactor (BWR), heavy water reactor (HWR) and gas cooled reactor (GCR) nuclear power plants operating worldwide in 1980 was estimated as 4X10+15 Bq(1). The total tritium activity discharged into the environment by nuclear fuel reprocessing plants operating in Windscale, UK, La Hague, France and Marcoule, France were 2X10+15 Bq in 1978(1). Annual tritium airborne release rates from the Savannah River Plant in South Carolina have ranged from 1.4X10+16 Bq to 9.9X10+16 Bq from 1974 to 1977 with an average of 4.1X10+16 Bq(1). An accidental pulse release of approximately 2X10+13 Bq of tritium from an industrial plant in Northern Switzerland moved through the sewers, to a sewage treatment plant, and was ultimately released to the River Glatt(2).

The optimum routine bioassay sampling frequency for tritium is once every 2 weeks (biweekly) for periodic acute intakes of tritium. Where exposure conditions are well established and anticipated tritium doses are low (e.g., <100 mrem for the year), less frequent intervals (e.g., monthly to quarterly) are adequate. However, the uncertainties with dose estimates associated with longer sampling intervals become much higher. Because of the 10-day effective half-life and the uncertainties associated with a possible organically bound tritium component, sampling intervals for HTO greater than 90 days are specifically not recommended. If the potential exposure to tritium is anticipated only for a very limited interval, starting and ending bioassay samples might be more suitable than participation in a continuing monitoring program.

Weekly urine counts for users of 10 mCi or more at any one time. Use liquid scintillation counting. /From table/

Special Monitoring for HTO Special monitoring may be required after unplanned or unusual exposures. When an unusual exposure has been suspected or reported, arrangements should be made to collect a urine specimen within a reasonably short period of time following the exposure, allowing for the achievement of body water equilibrium. For potentially high exposures, this sample might be a single voiding sample collected at the workplace. For less serious exposures, an overnight (simulated 12-hour) or simulated 24-hour sample provides confidence that body equilibrium has been achieved and may be more convenient. Follow-up sampling should be performed to confirm the initial sample results if implied doses might exceed 100 mrem. Additional follow-up samples may be warranted to verify the applicability of the 10-day retention half-time in the individual, or to assess a more suitable half-time. ... Once an exposure has been evaluated, elevated urine samples might be expected for some time (several months). If the worker returns to work that involves potential tritium exposure, a more frequent sampling program may be required until normal baselines are reestablished. During this time period, consideration may need to be given to the possibility that additional low-level uptakes of tritium might occur, which could be undetectable due to variability in the excretion pattern of tritium retained from the earlier intake.

Tritium is a radionuclide uniformly absorbed by the body. The purpose of cytomorphological and cytochemical leukocytes examination in tritium-affected workers was early detection of initial health disorder caused by tritium contamination. Cytoplasm and nuclear morphological changes were analyzed by colored blood smear microscopy. The enzyme activity in granulocytes was examined by cytochemical methods. Morphological changes were found in 47.17% of the subjects (N=53) and in 2% (N=52) of the controls. Chromosomal aberrations in lymphocytes were found in 49.05% of the exposed workers and in 2% of the controls. The granulocytes enzyme activities were significantly diminished in the exposed workers (p < or =0.001). The average level of beta radiation found in the urine of those affected by tritium was 3.46 kBq/L, while it was significantly lower in the others: 0.35 kBq/L. The enzyme activity decreases after 5 yr of tritium exposure. Nuclear and cytoplasm changes as well as lowered enzyme activity in granulocytes were found in tritium-contaminated workers. Interdependence of cytomorphological and cytochemical changes was established. There was no correlation between cytochemical changes and granulocytes count.

Tritium is a weak beta emitter that is not detectable by normal survey instruments or by whole body counting. Detection of exposure is by urine samples, which show excretion immediately after exposure. The first voiding water exposure should not be used because dilution by preexposure urine may cause a falsely low reading. The sample is counted by liquid scintillation techniques. A conservative rough rule of thumb based on the peak urine concentration after a single acute exposure, is that 37 Bq (1 nCi)/L of tritum equates to a total integrated whole-body dose of about 100 uSv, if the person is not treated by forcing fluids.

Currently, the tritium present in the environment /from natural sources/ ... estimated to be about ... 10 to /100/ ... megacuries ... .

Tritium occurs naturally to the extent of about 1 atom per 10+18 hydrogen atoms(1) as a result of nuclear reactions induced by cosmic rays in the upper atmosphere(1,2).

The principal source of natural tritium is the nuclear reactions induced by cosmic radiation in the upper atmosphere, where fast neutrons, protons, and deuterons collide with components of the stratosphere to produce tritium. Tritium has also been observed in meteorites(1).

A significant amount of tritium from the sun's surface is believed to be brought to the earth by solar wind and flare emissions. This tritium is rapidly incorporated into water molecules and mixed into the water of the atmosphere, hydrosphere, and biosphere(1).

Under normal conditions the total atmospheric content of molecular T2 gas is only 11 g(1).

The level of tritium in atmospheric hydrogen increased from 3800 TU in 1948-9 to 490000 TU in 1959. /TU (Tritium Unit) signifies a ratio of 1 atom of tritium per 1X10+18 atoms of hydrogen/(1).

SOURCE DOMINATED: The concn of tritium in the atmosphere over the Bikini Atoll increased by over hundredfold when thermonuclear testing was being conducted in March, 1954(1). It has since subsided as a result of the ban on atmospheric weapon testing and also due to the half-life of the isotope(1).

Under the implementing regulations of the Resource Conservation and Recovery Act (RCRA) [specifically at 40 CFR 261.4(a)(4)], source, special nuclear and by-product material as defined by the Atomic Energy Act of 1954 (AEA) is excluded from the definition of solid waste (and thus, from the RCRA hazardous waste management requirements). ... Accelerator-produced tritium, on the other hand, does not qualify for this exclusion (since the tritium is produced by a linear accelerator, and does not involve the production or utilization of special nuclear materials or the extraction or concentration of source material). ... Pursuant to the RCRA regulations, it is the responsibility of the generator of a waste to determine if that waste is subject to the hazardous waste requirements [40 CFR 262.11].

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 100 Ci or 3.7x10+12 Bq. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b).

(AL) ALABAMA 20000 pCi/l

(CA) CALIFORNIA 20000 pCi/l

(CT) CONNECTICUT 20,000 pCi/l

(IL) ILLINOIS 20,000 pCi/l

For more State Drinking Water Standards (Complete) data for TRITIUM, RADIOACTIVE (6 total), please visit the HSDB record page.

Pursuant to the Atomic Energy Act, discharges and releases of tritium to waters from DOE facilities are regulated by DOE and those from licensed nuclear facilities are regulated by NRC or NRC Agreement States. Under the Safe Drinking Water Act, the Environmental Protection Agency (EPA) has established the standard for tritium in water from drinking water systems. EPA and States also use this standard for protection of ground water that may be used as drinking water. DOE requirements prohibit DOE operations from releasing effluents that would cause a drinking water system to exceed this standard.

The biological half-life of tritium in the body following intake of tritiated water has been found to range from 2.4 to 18 days among 300 individuals. /Tritiated water/

The body excretes tritium with a biological half life of 8-14 days (10.5 day avg), which can be reduced significantly with forced fluid intake.

In two chronically-exposed tritium dial painters, ...effective half-lives for tritium of two separate tritium pools ranging from 21 to 26 days for the first pool and 280 to 550 days for the second pool of tritium /were reported/. ...Biological half-lives for tritium in chronically exposed tritium dial painters of 12.1 to 13.4 days /were also reported/.

Tritiated water (HTO) has a short biological half-life in the human body of 7 to 14 days, which both reduces the total effects of single-incident ingestion and precludes long-term bioaccumulation of HTO from the environment. Biological half life of tritiated water in human body, which is a measure of body water turn over, varies with season. Studies on biological half life of occupational radiation workers for free water tritium in the coastal region of Karnataka, India show that the biological half life in winter season is twice that of the summer season. (Wikipedia)

Because of the low energy and short range of the beta particles, tritium does not pose an external radiation hazard; the radiation is not sufficiently energetic to pass through skin. However, tritium is readily taken into the body, presenting an internal radiation hazard.

When exposed to tritiated water vapor via inhalation, people will absorb 98-99% of the activity inspired through the respiratory system. Uniform distribution throughout body fluids occurs within 90 min. Also, when exposed to such an atmosphere, tritium entering the body through the total skin area will approx equal that entering the lung. Elemental tritium (T2 or HT) is much less readily assimilated. Approx 0.004% of such activity inspired is absorbed, apparently after preliminary oxidation in the lung. Negligible amt of elemental tritium are absorbed through the skin. /Tritiated water/

Tritium, as tritiated water, is readily absorbed into the bloodstream from the gastrointestinal tract ... and distributes as body water. /Tritiated water/

The /radiation/ dose to the body if tritiated material is uniformly deposited in body water is approx 190 mrem/mCi.

For more Absorption, Distribution and Excretion (Complete) data for TRITIUM, RADIOACTIVE (20 total), please visit the HSDB record page.

Used to boost fission or fusion in nuclear weapons; Also used in tracers for biological and environmental studies and in luminous paints for exit signs, airport runways, and watch dials; [Argonne]

EPA has set the maximum contaminant level in drinking water at 20,000 pCi/L. Surface waters usually contain about 10-20 pCi/L. [Argonne]

Significant uses for tritium are in fission bombs to boost their yield, in thermonuclear weapons (the hydrogen bomb), in luminescent signs, and in night-vision military applications. Tritium absorbed on metals are a source of neutrons when bombarded with deuterons. Mixed with zinc sulfide, it produces radioluminescence that is used in luminescent paint and on watch dials. Gaseous tritium in the presence of zinc sulfide produces a small, permanent light source found in rifle sights and exit signs. Tritium is also a good tracer because it does not emit gamma radiation. Hydrological studies with HTO are used to trace geological water and the movement of glaciers. It is also used as a tracer for hydrogen in chemical studies and biological research. In medicine, it is used for diagnosis and radiotreatment.

Bombarding particle in cyclotrons, activator in self-luminous phosphors, in cold cathode tubes, tracer in biochemical research and various special problems in chemical analysis, luminous instrument dials, thermonuclear power research.

In fusion-based thermonuclear weapons (hydrogen bombs) ... Widely used as a radioactive tracer in chemical, biochemical, biological and hydrological research.

As source of irradiation in electron capture detectors.

First prepd by the bombardment of deuterophosphoric acid with fast deuterons: Oliphant et al; Proc Roy Soc A144, 692 (1934); Bonner, Phys Rev 53, 711 (1938). Produced commercially from (6)Li by slow neutron bombardment. ... Prepn by neutron irradiation of lithium fluoride: Jenks et al, US Patent 3,079,317 (1963).

Numerous reactions are available for the artificial production of tritium and it is now made on a large scale by neutron irradiation of enriched lithium-6 in a nuclear reactor. The lithium is in the form of an alloy with magnesium or aluminum which retains much of the tritium until it is released by treatment with acid. Alternatively the tritium can be produced by neutron irradiation of enriched LiF at 450 degrees in a vacuum and then recovered from the gaseous products by diffusion through a palladium barrier.

A small quantity of tritium is produced through neutron capture by deuterium in the heavy water used as moderator in /nuclear/ reactors.

Tritium is produced as a minor product of nuclear fission. The yield of tritium is 1-2 atoms in 10,000 fissions of natural uranium, enriched uranium, or a mixture of transuranium nuclides.

Tritium: ACTIVE

US Patent 4173620, assigned to Doryokuro Kakunenryo Kaihatsu Jigyodan, Japan describes a method of producing a high purity tritium gas by extracting tritium from tritium-containing heavy water.

The principal USA site of production is the Savannah River Plant near Aiken, SC. /Former/

The United States has not produced tritium since 1988, when the Department of Energy's (DOE's) production facility site in South Carolina closed. Immediate tritium needs are being met by recycling tritium from dismantled U.S. nuclear weapons. According to DOE, resumption of tritium production is essential for maintaining the U.S. nuclear weapons stockpile. ... On December 22, 1998, the DOE Secretary announced that he had chosen the light water reactor technology as the primary means for tritium production; the accelerator design will be retained as a backup. He selected the Tennessee Valley Authority's (TVA's) Watts Bar Nuclear Plant and Sequoyah Nuclear Plant, Units 1 and 2, in Tennessee as the preferred facilities for producing future supplies of tritium. ... The tritium will still be shipped to (in the form of tritium producing burnable absorber rods) and extracted at the Savannah River site.

Tritium /can be concentrated/ by electrolysis of tritiated water. ... Low temp (20-25 K) distillation ... has been successfully applied to the separation of tritium from the other hydrogen isotopes. ... Concentration by gas chromatography has also been demonstrated.

The ordinary isotope of hydrogen, H, is known as protium. In 1932, Urey announced this discovery of a stable isotope, deuterium (2H or D) with an atomic weight of 2. Deuterium is present in natural hydrogen to the extent of 0.015%. Two years later and unstable isotope, tritium (3H) with an atomic weight of 3 was discovered.