THE CARCINOGENIC, MUTAGENIC, TERATOGENIC
AND TRANSMUTATIONAL EFFECTS OF TRITIUM
CITIZENS AWARENESS NETWORK
WWW.NUKEBUSTERS.ORG
A P R I L 1 9 9
4
Updated January 2001
Abridged by
Contact:
Deborah Katz
Executive Director
Citizens Awareness Network
Compiled by:
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TRITIUM
Tritium is a radionuclide
emitted as waste from pressurized water nuclear reactors, heavy water nuclear
reactors and the new generation of nuclear reactors. It has been an integral part of the nuclear
weapons industry: tritium was released into the atmosphere as part of weapons
testing in the 1950's and 60's. It is a
beta emitter and has a half-life of 12.5 years.
It decays to an isotope of helium, releasing a neutrino and a beta
particle (an electron). The electron is
slow-moving and has a very short range.
Tritium was believed to be a
relatively benign radionuclide because of the weakness of the beta radiation
emitted when it decays. The beta
electron is a small particle that passes readily through most barriers. The dangers of tritium come from inhalation,
ingestion, and absorption.
Tritiated water (HTO) passes
through the human body in 12 days.
However, when the radionuclide unites with carbon in the human body,
plants, or animals, it becomes organically bound (OBT) and can remain in the
human body for 450 to 650 days. One
study found traces of tritium in the body 10 years after exposure.(24)
As tritium makes its way up
the food chain it may become more concentrated.(16) Pigs fed with tritiated
food themselves became tritiated, as did their offspring. The blood, heart, and kidneys of the piglets
were more tritiated than the mother .(23)
Tritium is carcinogenic,
mutagenic, and teratogenic. (21) Human beings can receive chronic exposure to
OBT through the ingestion of plants and animals exposed In the effluent
pathway, in addition to direct uptake through inhalation, absorption and
drinking contaminated water. Especially
sensitive to the effects of tritium are rapidly growing cells such as fetal
tissue, genetic materials and blood forming organs. (2,12,19, 21, 20)
Tritium is dense and has a
short track length. It releases all its
activity at one time. This makes it more
potent and similar to soft x-rays, which are more effective than hard x-rays.
(15) When and where it deposits its radioactivity, it creates
at least one lesion in the cell.
This lesion must be repaired within 24 hours or the cell will be carcinogenic
when it eventually divides.(26, 30) There may be a threshold below which the
repair mechanism is not activated in the body, (13,15,27, 32) therefore, low
levels of chronic radiation exposure can accumulate in the body without the
repair system being activated. (11, 25, 27,30,32, 36)
Tritium has a transmutational
effect which is mutagenic. After the
particle releases its radioactivity into the cell, a helium ion is formed. The helium springs away from the 9-particle
and severs the bond with the compound to which the tritium had attached
itself. The compound acquires a positive
charge and becomes chemically active.(22)
It then can attach itself to
a ring of a protein precursor that will make up the chromosomal strands in the
DNA. Depending on the ring it attaches
to, it can affect the protein precursors and damage the DNA. This would create a mutational effect.(22)
Radiological research has
found a correlation between tritium and cumulative genetic injury. (21) There
was found in successive generations a reduction in relative brain weight,
reduction in litter size, and increased reabsorption of embryos. Correlations have been found in
epidemiological research between tritium and Down’s' Syndrome. Associations have also been found between
low-level radiation and Down's Syndrome.(6,7,8,10,31)
____________________________________________________________________________________________
Annotated bibliography of
low-level radiation studies and tritium research
Down’s Syndrome
I E. Alberman, J.A. Polani, Fraser Roberts, C.C. Spicer, M.
Elliot, E. Armstrong, 'Parental Exposure to X-irradiation and Down’s
Syndrome."
Effect of radiation on
increase in Down's Syndrome was greatest in subgroup where X-rays were received
more than ten years before conception.
There was significant increase of 'ever" X-rayed mothers in Down's
Syndrome group. The size or dose of
X-ray was less important than the cumulative effect, as if damage was not
followed by repair.
2.· V. BEIR, 'Health Effects of Exposure to Low Levels of
Ionizing Radiation."
Report stated that there was
no threshold for the effects of radiation when the brain is in its most
sensitive stage of development. This was
especially true from 8-1 5 weeks through 22 weeks of gestation.
3.· Susan Harlap, 'Down's Syndrome in
Research found that there
were environmental factors involved in the etiology of Down's Syndrome. Harlap compared rates of Down's Syndrome in
different groups in
4.· N. Kochupillai,I.C. Verma, M.S. Grewal, V. Remalinggaswami,
'Down's Syndrome and related abnormalities in an area of high background
radiation in coastal Kerala.' Nature, 262 (1976) 60-61.
Research compared high
background population to control with low background radiation. The observed frequency was higher than in
controls and significant. Higher
frequency of cases of Down's Syndrome born to mothers aged 30-39. There was an association suggested between
low dose radiation exposure of older maternal age, suggesting that the damaging
event accelerates oocyte aging and causes primary trisomy rather than
translocation trisomy.
5· CN Rasmey, Ellis, and Zeally, 'Down's Syndrome in the
Lothian Region of
Observable increases in
Down's Syndrome were noted in Lothian Region of
6· Sheehan, M. Patricia and B. Hillary Irene, 'An Unusual
Cluster of Babies with Down's Syndrome Born to Former Pupils of an
Sheehan found a cluster of
children born with Down's Syndrome (8) to mothers who attended a girls school
as adolescents, during the Windscale fire at that reprocessing reactor. The school was in the effluent pathway and
the radionuclide released was tritium.
There were 30 birth abnormalities in all in this small population.
7 A.T. Sigler, et al 'Radiation exposure in parents with
children with mongolism (Down's Syndrome).' Bulletin of
Radiation exposure increased
the risk of mongolism in parents. There
was validation of the view concerning cumulative radiation damage to genetic
material. Exposure was result of fluoroscopic
and therapeutic radiation.
8 K. Sperlind, J. Pelz,RD.
Wegner, 1. Schulzke and E. Srruck, 'Frequency of Trisomy 21 in
Increases in Down's Syndrome
were observed in
9.· Uchida, Irene and
Elizabeth and J. Curtis, 'A Possible Association Between Maternal Radiation and
Mongolism.' Lancet (10/14/61):848-850.
There is a strong association
between the incidence of mongolism and a history of maternal abdominal
radiation. Radiation effect may be
age-dependent.
10 T. Zuftan and W. Luxin, 'An Epidemiological investigation of
Mutational Diseases in the High Background Radiation Area of
There were increases in
Down’s Syndrome found in high background radiation area. Increases in cancer were not found. Average background dose was 330 mR/yr and 114
mR/yr in control group. There was a
higher rate of cancer in control group, which had received a greater number of
medical X-rays.
Tritium
11 D.F. Cahill and C.L. Yuile, 'Tritium Irradiation of Mammalian
Fetus." Radiation Research 44
(1970) : 727.
Offspring conceived by
parents subjected to low level lifetime exposure manifest effects at HTO
activity levels 10-100 times lower than those required during exposure in utero
only.
12 L.A. Carsten and S.L. Cummerfored, 'Dominant Lethal Mutations
in Mice Resulting from Chronic Tritiated Water lngestion.' Radiation Research
66(1973):609.
Two successive generations of
mice were exposed to continued ingestion of tritiated water. In second-generation females, there was a
significant reduction in the number of viable embryos.
13 A.L. Carsten, et al, ' 1989 Summary Update of the Brookhaven
Tritium Toxicity Program with Emphasis
on Recent Cytogenic and Lifetime-Shortening Studies in
Proceedings of the Third Japan-US workshop on Tritum Radiobiology and Health
Physics.' (Edited by S. Okada),
There may be an effect at
very low doses where the radiation inhibits the repair mechanism. This may occur during tritium
irradiation. Theory consistent with the
track structure calculations of Goodhead using very weak X-rays. There was significant reduction in the number
of viable embryos resulting from matings between animals maintained on tritium
diet. There was no effect on breeding
effectiveness.
14R.L. Dobson and M.E.
Cooper, 'Tritium Toxicity - Effects of low-level 3HOH Exposure in Developing
Female Germ Cells in the Mouse,' Radiation Research 58. p. 91.
Adult female mice were
maintained on tritium levels 8.5, 0.85 and 0.085 Ci/ml of body water from day
of fertilization. In female offspring
exposed to tritium from conception and sacrificed at 14 days, primary oococytes
were decreased below control number by 90% at 8.5, and significantly at 0.085
level.
15 D.T. Goodhead and H. Nikjoo, "Current Status of
Ultrasoft X-ray and Track Structure Analysis as Tools for Testing and
Developing Biophysical Models of Radiation Action.' Radiat. Prot.
Dos. 31, No. 1/4 (1990) 343-352.
Authors conclude that
ultrasoft X-rays are more effective than equal doses of hard X-rays. Their RBEs increase with decreasing X-ray
energy down to very small track lengths of 7 nm. Low energy electron track ends are a
predominate cause of cell inactivation in all low LET radiations. (Ultrasoft
X-rays are very similar in energies and track lengths to tritium 8-radiation).
16 Kirchman, et al, 'l 973 Studies on the Food Chain
Contamination by Tritium.' In Tritium, editors Moghissi and Cater, Messenger
Graphics,
Tritiated grass eaten by cows
has been shown to be effectively transferred to their milk. OBT levels in their milk were 10 times higher
in cows fed on tritiated grass than cows fed on HTO.
17 D. Macintosh, S. Lung, F. Tsai and J. Spengler, 'A
Preliminary Assessment of the Potential Human Exposure to Tritium Emissions
from the Yankee Atomic Electric Company Nuclear Power Facility Located Near
Rowe, MA.' Harvard University School of Public Health, Dept .of Environmental
Health 7(1993)
Graduate students, under the
supervision of J. Spengler, conducted a preliminary assessment of potential
exposures and doses to the
18 ].W. Laky, et al, 'Some Effects of Lifetime Parental Exposure
to Low-Levels of Tritium on the F2 Generation." Radiation Research 56,
(1973) :1 71.
Research done on effects of
low-level exposure to tritiated water.
Continued exposure calculated as whole body dose rates 3 to 3,000
mrads/day produced a 30% reduction in adult Fl male testes, but no impairment
in growth or reproductive ability.
Statistically significant effects on F2 neonates were: reduction in
relative brain weight, decreased body weight, decreased litter size and
increased reabsorption. Brain and testes
contained approximately 1 00% and 50% greater tritium activities than the
average in other tissues.
19 J.W. Lasky, and S.J. Bursian, Radiation Research 67, (1976) :
314.
Rats were exposed to constant
tritium activities of 10 uCi/ml of body water for 42 days beginning first day
of pregnancy or birth. In males exposed
from birth or first day, there was a significant reduction in the testes weight
and sperm content. In females exposed
there was a significant reduction in F2 litter size and an increase in the
number of reabsorbed embryos. The group
most sensitive to low-level exposure was the one exposed from first day of
pregnancy.
20 D.J. Mewissen, 'Cumulative Genetic Effects from Exposure of
Male Mice to Tritium for Ten Generations.' IAEA Symposium on Biological
Implications of Radionuclides Released from Nuclear Industries, (1 979).
Data established the
existence of cumulative genetic injury and the existence of cumulative genetic
injury at the 9th generation. Their F2
offspring (unexposed) exhibited a significant increase in dominant lethal
mutations resulting in a decrease in litter size.
21 T .Straume, ' Health Risks from Exposure to Tritium.'
UCRL-LR-105088,LawerenceLivermoreLaboratory,
Tritium is more hazardous to
health than other types of low-level radiation.
Tritium is about 1.5 times as carcinogenic, 2-5 times as mutagenic, and
2 times as teratogenic.
22 G. Tislajar-Lentulis, P.Hennenberg and L.E. Feinendegen, 'The
Oxygen Enhancement Ratio for Single and Double
Researchers found that a
third of single strand DNA breaks caused by the decay of tritium in 6-thymidine
were due to transmutation. This is over
and above the radiational effect.
23 M. Van Hees, et al, 'Retention in Young Pigs of OBT Given
During Pregnancy and Lactation.' Radiat. Prot. dos. 16, no 1-2, (1971) : 123-126.
Pigs fed with tritiated food
themselves became tritiated. They passed
on tritium to their offspring. The
blood, heart, and kidneys of the young piglets were more tritiated than the
tritiated foods fed their mother.
24 H. Wasserman, and K. Solomon, 'Killing Our Own," N.Y.
Dell. (1982) :190-193.
There is a long residency
period in the body of very low concentrations of tritium. A 1981 study of former American atomic
workers showed a majority with tritium levels still ten times above normal. Study found that tritium can remain in the
body for up to ten years.
Low-Level Radiation
25 K.F. Baverstock, D. Papworth, and J. Vennart, 'Risk of
Radiation at Low Dose Rates." Lancet, 1, (1981) 430-433.
Researchers studied workers
involved in assemblage of instrument-dials made luminescent with radium. Significance found for breast cancer induced
by gamma radiation. Exposure at rate
of 0.1 rad per 8 hours, allowing
adequate time for repair from exposure.
Although the luminizer appears to be a high dose study, it demonstrates
the inability of the body to adequately repair after exposure to low-level
radiation.
26 M.A. Bender, 'Significance of Chromosome Abnormalities.'
(1984) :281-289 in boice.
Bender investigated the
repair of chromosome breaks incurred through exposure to radiation. In discussing repair of chromosome breaks, he
reports repair half-times which are 'typical of the order of 1 or 2 hours.'
27 L.W. Brackenbush, and
Researchers state that 'Since
most cells repair radiation damage with a characteristic time ranging from a
few minutes to a few hours, it is evident that irreparable or mispaired damage
must dominate the low-LET radiation effect at low dose rates.'
28 I.D. Bross, et al, 'A Dosage Response Curve for the One Rad
range: Adult Risk for Diagnostic Radiation.' Amer. ]our. Pub.
Health, 69, no. 2, (1979).
Bross investigated the effects
of diagnostic medical trunk X-rays on 220 men with non-lymphatic leukemia and
270 controls. Research suggests that
most heart disease is 'prompted' by radiation exposure. The doubling dose of radiation for leukemia
was determined to be 5 Rems.
29
Dr. Cobb analyzed raw health
statistics in the
30 H.J. Evans, K.E. Buckton, G.E. Hamilton and A. Garothers,
'Radiation-induced chromosome aberrations in nuclear-dockyard workers.' Nature,
277, (Dec. 1979) : 531 -S34.
Researchers demonstrated a
significant dose-dependent increase in chromosome aberrations in peripheral
blood leukocyte chromosomes in a population of monitored nuclear-dockyard
workers, subject to occupational radiation exposure within maximum permissible
limits 5 rem per year. The observed increase
in dicentric aberrations is not large but is a direct expression of increased
genetic damage caused by radiation exposure.
It is possible to detect a biological effect at the chromosome level to
ionizing radiation below the internationally agreed maximum permissible levels.
31 L.E. Feinendegen, et al, 'Biochemical and Cellular Mechanisms
of Low-Dose Radiation Effects.' Internationa Jjournal of Radiation, Biology 53,
no. 1, (1988) : 23-27.
Researchers studied the
ability of irradiated cells to repair themselves. Feinendgen states, 'Whereas the majority of
single-strand breaks and base changes are very efficiently and quickly repaired
with half-times less than 1 hour, the reconstitution of a double-strand break
probably lasts much longer, perhaps up to several hours, and not all double-strand
breaks are fully repaired.'
32 J. Gentry, et al, 'An Epidemiological Study of Congenital
Malformations in
Congenital malformation rates
were studied in association with high and low background areas in
33 D.T. Goodhead, 'Spatial and Temporal Distribution of Energy.'
Health Physics, 55, (1988) : 231-240.
Goodhead studied the ability
of cells to repair themselves after exposure to radiation. He suggests that the repair system may need a
'kick' to get started. He states: '...it
is conceivable that the cell would repair relatively more efficiently if there
were more damage to stimulate its repair process.'
34 A.J. Grosovsky, and J. Little, 'Evidence for linear response
for the induction of mutations in the human cells by X-ray exposures below 10
rads.' Proc. Natl. Acad.
The induction of thioguanine
resistance was studied in continuous human lymphoblast cultures exposed to
daily X-ray exposures of 1, 2.5, 5 or 10 rads for periods up to one month. The effects of small daily fractions were additive
suggesting that doses as small as 1 rad are mutagenic in human
lymphoblasts. A liner increase in
mutation frequency was observed over this dose range with no apparent
threshold. Results suggest that for
human lymphoblasts, the mutagenic risk of low dose of X-rays can be accurately
estimated by linear extrapolation from high dose effects.
35 M. Otake, and W. Schull, 'In utero exposure to A-bomb
radiation and mental retardation; an assessment.' British ]our. Radiol., 5 7, (May 1984) : 409414.
Otake and Schull studied the
incidence of mental retardation in Japanese A-bomb survivors. They found that the 8th through the 15th week
of gestation was especially significant.
Implication that 1 rad absorbed by the fetus during this period may
double the rate of mental retardation.
36 A. Upton, "Prevention of Work-Related Injuries and
Disease: Lessons from Experience with Ionizing Radiation." Amer.
)our. Indust. Med., (1987) : 300-301.
37 C. Waldren, et al, "Measurements of low-levels of X-ray
mutagenesis in relation to human disease." Genetics, 83 : 4839-4843.
Waldren and coworkers studied
the direct measurement of the effects of low doses of radiation and other
mutagens. Extrapolation procedures were
not used to estimate effects. The data
demonstrate 'that the true mutagenesis efficiency at low doses of ionizing
radiation that approximate human exposures is more than 200 times greater than
those obtained with conventional methods.' With increasing dose, a point
reached, where the mutational effect can not be detected in the chromosomes
because the cell is killed off.
Unequivocal mutagenesis took place for dose as low as 2.4 rads. Waldren states that 'observed mutational
efficiency at low doses is considerably higher than that observed at higher
doses.'
GLOSSARY
A
Activity -
The number of atoms of a radioactive substance that disintegrate per unit of
time.
Air Inversion -
A condition in which a dense substance lies over a less dense substance. In an
atmospheric temperature inversion, the air temperature increases and therefore
the density decreases with height. Such
inversions occur locally in very still air and tend to be stable because rising
air, warmed at the surface, loses its buoyancy and is trapped when it meets air
at the same temperature and density as itself so tending to reinforce the
inversion. Pollutants entering the air
close to the ground level are similarly trapped, and so temperature inversions
are sometimes associated with severe pollution incidents.
Alpha Particle
- A positively charged particle emitted by certain radioactive material
consisting of two neutrons and two protons.
A dangerous carcinogen when inhaled or ingested.
Atom - The
smallest unit of an element, consisting of a dense central, positively charged
nucleus surrounded by a system of electrons.
The structure is usually electrically neutral and is indivisible by
chemical reactions.
Atomic Nucleus
- The core of an atom, composed of protons and neutrons.
Atomic Waste
- Radioactive solids, gases and contaminated liquids produced by nuclear
reactions. Generally classed as high, intermediate, or low-level waste,
dependent on curie per liter count.
B
Background Radiation - Ambient radiation from outer space [cosmic] and
materials found at the surface of the earth.
Beta - A
type of radiation
Beta-Emitter
- A radioactive element characterized by its beta radiation.
Beta Particle -
A high energy electron emitted by decay in a radioactive nucleus. Can cause skin burns and, when ingested,
cancer.
C
Carcinogen - A cancer causing
substance or agent.
Chromosomal Strands -
Curies -
(radiation units). Units of measurement
used to express the activity of a radionuclide and the dose of ionizing
radiation.
D
Decay -
Gradual disintegration of radioactive material over time.
DNA -
(deoxyribonnucleic acid). The genetic
material of most living organisms which is a major constituent of the
chromosomes within the cell nucleus and plays a central role in the
determination of hereditary characteristics.
Dose - The
amount of energy absorbed in a unit mass, organ, or individual from
irradiation.
Down’s Syndrome
- A congenital condition characterized by mental deficiency and related to the
tripling of certain human chromosomes.
E
Effluent
- Liquid or gaseous radioactive discharge from a nuclear reactor.
Effluent Pathway – the pathway that radioactive waste travels after it is emitted from
a nuclear reactor.
Electron - A
negatively charged atomic particle, lighter than a proton or neutron.
Epidemiology
- A branch of medical science that deals with the incidence, distribution and
control of disease in a population.
Etiology -
All of the causes of a disease or abnormal condition.
Exposure -
Being exposed to radiation.
F
Fission -
The splitting of a nucleus into two lighter fragments, accompanied by the
release of energy and generally one or more neutrons. Fission can occur either
spontaneously or as a consequence of absorption of a neutron.
Fluoroscope
- An instrument used chiefly in industry and medical diagnosis for observing
the internal structure of opaque objects (as the living body).
Fuel Rod - A
single tube of cladding filled with uranium fuel pellets.
G
Gamma Ray -
High energy, short wavelength, electromagnetic radiation emitted by a nucleus.
H
Half-Life -
The time it takes for half of any radioactive substance to disintegrate.
Half-lives range from seconds to millions of years.
I
Ion - An
atom, molecule, or elementary particle that has lost or gained one or more
electrons, therefore taking on an electrical charge. A positive ion has lost
one or more electrons; a negative ion has gained one or more electrons.
Ionization -
The process of adding or removing electrons so as to form ions. Ionization can
be caused by high temperatures, electrical discharges, or nuclear radiation.
Ionizing Radiation - Alpha, beta, or gamma radiation, which, when passing through matter
can ionize it. Ionizing radiation can cause cell damage as it passes through
tissue.
Irradiated -
Having been exposed to or treated with radiation.
Isotope - A
radioactive variant of a common element with a different atomic weight but
equivalent atomic number. Isotopes are generally created by the fission
process.
L
Latent Period
- The amount of elapsed time between exposure and the first sign of disease
symptoms.
Low-Level -
Refers to radioactivity of low intensity.
M
Micro-Dosimetry
- Dosimetry involving micro-doses of radiation or minute amounts of radioactive materials.
Millirem [mr]
- One thousandth of a rem.
Molecule - A
group of atoms held together by chemical forces.
Mongolism -
See Down's Syndrome. A sudden variation; offspring differing from its parents
in one or more heritable characteristics
Mutation - changes
within the chromosome or the gene.
N
Neutrino - A
subatomic particle of negligible mass, named by Enrico Fermi.
Neutron - An
uncharged particle in the nucleus of every atom heavier than hydrogen. A free neutron is unstable. with a
half life of 13 minutes, it will decay into a proton, electron and a neutrino.
Nondisjunction
- Failure of two chromosomes to separate subsequent to meta phase in meiosis or
mitosis so that one daughter cell has both/and the other, neither of the
chromosomes.
Nuclide -
Any atom that exists for a measurable length of time. A nuclide can be identified by its atomic
weight, atomic number, and energy state.
O
Oocyte - An
egg before maturation: a female gametocyte.
Organically Bound - Held in chemical or physical combination.
P
Photon - A
'packet' of energy with no mass, which travels at the speed of light. Photons
range from very low energies [such as infrared and visible light], moderate
energies [ultraviolet and X-rays] to high energy [gamma].
Pressurized Water Reactor (PWR) - A reactor in which the heat from the nuclear core
is transferred to a heat exchanger under constant pressure to achieve a high
water temperature without boiling. A
secondary circuit produces steam for the generators.
Proton - A
elementary particle with a single positive charge that is a part of all nuclei.
R
Rad - A
measure of exposure to, or the absorbed dose of radiation.
Rad Waste- radioactive
waste.
Radiation - The
emission of neutrons, alpha particles, beta or gamma rays from a radioactive
source.
Rem – The
unit measuring an absorbed dose of ionizing radiation in biological matter;
abbreviated from 'Roentgen Equivalent,
S
Soft X-Rays -
(soft radiation) Ionizing radiation of low penetrating power, usually used in
reference to x-rays of long wavelength.
T
Teratrogenic (Teratogen) - Any environmental factor that acts on a fetus to
cause congenital abnormality.
Transmutational
- The transformation of one element into another by bombardment of a nucleus
with particles. For example, plutonium
is obtained by the neutron bombardment of uranium.
Tritium - A
radioactive nuclear by-product, also known as H3, consisting of a hydrogen
nucleus, or proton, with two additional neutrons.