An Overview of Hanford and Radiation Health Effects
Hanford is the name of a former nuclear weapons production site located in south central Washington state. Established in 1943, Hanford released radioactive materials into the air, water and soil. The releases occurred mainly as the result of routine operations but were also due to accidents and intentional releases. Many of those who lived in the areas downwind from Hanford or who used the Columbia River downstream from Hanford received doses of radiation. Those doses may have caused health problems or might cause them in the future. The basic assumption of radiation protection is that any dose of radiation poses a health risk. This publication presents some basic information about hanford, the radiation it released and how people were exposed to the radioactive contamination. It also provides an introduction to the possible health effects from radiation exposure. because the largest estimated exposure from Hanford could affect the thyroid gland, this publication includes a special section on thyroid disease. Also included are descriptions of hhin publications that offer further information.
Because of the secrecy surrounding nuclear weapons production, the public did not know much about hanford's operational details until 1986. by february of that year, citizen pressure had forced the u.s. department of energy to release 19,000 pages of hanford historical documents that had been previously unavailable to the public. These pages revealed there had been huge releases of radioactive materials into the environment that contaminated the columbia river and more than 75,000 square miles of land. many people were outraged at the four decades of secrecy and deception.1 They felt they had been betrayed by their own government. They demanded to know how the government could have kept such dangers secret for so long.
After the plutonium was removed from the reactors, it had to be separated and purified for use in nuclear weapons. Separating the plutonium resulted in radiation being released into the air. Winds carried hanford's airborne radiation throughout eastern Washington, northeastern Oregon, northern Idaho and into Montana and Canada. Food grown on contaminated fields, and milk cows grazing there, transferred the radiation to people who ate the food and drank the milk. The years of highest releases to the air were 1944 through 1951, with 1945 being the largest. Hanford Radiation Studies Begun Because of public concern and anger over the once-secret information, a
scientific panel, the Hanford health effects review panel, was convened in September
1986 to examine the newly released documents. The panel recommended that two
studies be done to determine To determine how much radiation people were exposed to, the U.S. Department of Energy began the Hanford environmental dose reconstruction project (HEDR) in 1987. Funding for HEDR was transferred to the centers for disease control and prevention (cdc) in 1992. The reason for this transfer was the Department of Energy's conflict of interest since the department also is in charge of Hanford operations. Some people remained skeptical because CDC kept Battelle Memorial Institute as the contractor to do most of the hedr work. Battelle has been a Hanford contractor since 1965.
In addition to the hedr project (to determine how much radiation people were exposed to), the federal government sponsored a second study, the hanford thyroid disease study (HTDS). CDC began HTDS in 1989 and plans to complete it in late 1998. CDC has contracted with the Fred Hutchinson cancer research center in Seattle to carry out the study. The HTDS is investigating whether thyroid disease, including thyroid cancer, is increased among people who were exposed as infants and children to iodine-131 from hanford. By its completion, the study will have examined over 3,000 people for thyroid disease. Radiation Health Effects: How Radiation Causes Harm To understand why cancer and thyroid disease are of concern, it is useful to know how radiation can cause harm to the body. When radiation enters the body and hits a cell, one of four things can happen:
(2) It may damage the cell, but the cell may be able to repair the damage before producing new cells; (3) It may damage the cell in such a way that the damage is passed on when new cells are formed; or (4) It may kill the cell.
If the damage to a cell is not repaired and is passed on to new cells (number 3 above), a cancer can begin to grow. It may take years or even decades for a cancer to grow large enough to be discovered. This period between exposure to radiation and the discovery of cancer or other health effects is called the latent period. The latent period varies for different types of health effects and different types of radiation doses. When radiation kills a cell (number 4 above), there will be acute (immediate) health effects if the dose is high and many cells die. An example of an acute effect is death within days or weeks from radiation sickness, as happened to the highly exposed people in the atomic bombings in japan. Other acute effects include vomiting and loss of hair. From what is currently known, doses to people from Hanford's environmental releases were not enough to produce immediate or direct effects.
cancer Radiation can cause most types of cancer. Some cells or organs - breast tissue and the thyroid, for example - are very sensitive to radiation. Others, such as bone cells, are not as sensitive. Whether or not exposure to radiation will cause cancer depends on a variety of factors. These include: the amount and type of radiation DOSE; individual characteristics that make some people more susceptible to cancer than others; age; gender; whether the exposure occurred over a short or a long time; and the presence of other substances that enhance the cancer-causing power of radiation. There has been much controversy over the extent to which low-dose radiation causes cancer. One of the more widely-known reports was published in 1990 by the fifth committee on the biological effects of ionizing radiations (known as BEIR V).2 BEIR V concluded that information from scientific studies about people receiving low doses was insufficient to determine cancer risk. Overall, BEIR V concluded that cancer risk from radiation exposure is higher than regulatory and advisory groups had previously described. BEIR V estimated cancer risk but acknowledged uncertainty concerning these risk estimates. BEIR V estimated that for every 10,000 adults exposed over a short time period to 1 rem of radiation, eight would die from radiation-induced cancer.3 If the exposure took place during childhood, the risk for fatal cancer was estimated to be twice as high. BEIR V also concluded that when the dose was received over a long time, the lifetime risk of death from cancer was lower by a factor of 2 or more than if the same dose had been received over a short time. Most hanford exposures occurred over long times (months, years or decades). Additionally, two other scientists have been sharply critical of BEIR V. Rudi H. Nussbaum and Wolfgang Kohnlein have pointed out a number of inconsistencies within the beir v report. They also argue that studies published after beir v support the position that there is a greater risk of health effects from chronic low doses than is reflected in current radiation protection regulations.6 Why there aren't clear answers Scientists are unable to determine with certainty the relationship between cancer and radiation exposure. Many people find this frustrating. However, it is important to know.
Thyroid Disease The type of radiation that caused the highest doses downwind from Hanford, iodine-131, concentrates in the thyroid gland. Exposure to some types of radiation has been shown to cause thyroid disease, including cancerous and noncancerous thyroid growths. The htds is gathering information on all types of thyroid disease, whether or not previous studies have suggested links between radiation exposure and thyroid disease. While the htds will not be completed until late 1998, thyroid disease studies from other types of radiation exposures may offer some comparisons to the hanford situation. Studies of environmental exposure to iodine-131
Nevada-Utah downwinders people who lived downwind (downwinders) from the nevada test site were exposed to nuclear fallout, including iodine-131, caused by atmospheric testing of nuclear weapons. A study of these downwinders suggests a dose-response relationship between the occurrence of thyroid growths (nodules and cancer) and iodine exposure. In this setting, a "dose-response relationship" means that the risk of having a thyroid growth (the response) increases as the dose increases. In other words, people with higher doses have greater risk than people with lower doses. The scientists who did the study concluded that the radioactive iodine exposure "probably caused" between one and 12 of the 19 cases of thyroid growths among the study population of about 2,500.7 Marshall Islanders In 1954 Marshall Islanders were exposed to radioactive fallout from a nuclear weapon test in the south pacific. They were exposed to some iodine-131, but most of the thyroid exposure came from other radioactive forms of iodine. the Marshall Islanders suffered both acute and delayed effects from radiation. eight years after the blast, some marshall islanders developed thyroid disease. After 27 years, the Marshall Islanders had an increased rate of hypothyroidism (underactive thyroid gland) and both noncancerous and cancerous thyroid growths. It is difficult to say that it was the iodine-131 or the other radioactive iodines alone that caused these thyroid problems because the Marshall Islanders also received external radiation. children living near Chernobyl In 1995 scientists reported that the rates of thyroid cancer were significantly increased among young people who were exposed to Chernobyl's radioactive fallout.8 before the 1986 accident, childhood thyroid cancer in the areas around Chernobyl was rare. The current rates are up to 200 times higher than normal. The rates in the table below are the number of thyroid cancers per million people. Childhood thyroid cancers are those thyroid cancers diagnosed before the children turn 15 years old. Most (about 85 percent) of the chernobyl thyroid dose came from iodine-131 and was received over a short time. The rest of the thyroid dose came from other radioactive isotopes of iodine. At Hanford, nearly all of the thyroid dose was from iodine-131 and was received over a number of years. HEDR estimated that children living downwind from Hanford received total thyroid doses in the range of 3 to 235 rad for the period 1944 through 1951. Because of uncertainties, the estimated dose could have been as high as 870 rad.10 Until further studies around chernobyl are completed, it is not clear if
radioactive iodine was the only cause of the
high rates of thyroid cancer. Among other possible contributors were an iodine deficiency in the exposed
population before the accident and a higher than normal sensitivity to the harmful effects
of radiation exposure among some of those exposed.11 Another contributor could have
been the greatly increased number of thyroid examinations after the accident.12
Medical Exposures to Iodine-131 Much of what is currently known about the health effects of iodine-131
comes from studies of the medical uses of iodine-131. one group of people exposed to
iodine-131 received a one-time high dose (thousands of rad) to treat hyperthyroidism (an overactive
thyroid gland). Another group
received a one-time low dose (50-100 rad) of iodine-131 for tests to diagnose thyroid
disease. Studies of these two groups of people do not show any link between iodine-131 and thyroid cancer.
However, the length of time people were studied varied. The longest study
followed people an average of 20 years. Scientists believe that the latent period for thyroid cancer
can range from five to more than 40 years. They believe that the very high doses of
iodine-131 used to treat people with hyperthyroidism result in killing off cells so that
cancer cannot develop.
External Gamma and x-ray
Radiation of the Thyroid
While there is not conclusive evidence linking iodine-131 and thyroid cancer, there is a link between
thyroid cancer and exposure to x-rays and gamma radiation. studies of
people who received x-ray treatments of the head and neck show that x-rays can cause
thyroid cancer. Thyroid cancer was the first solid tumor to show an increased rate in
Japanese atomic bomb survivors who were exposed to gamma radiation.
Parathyroid Disease
Parathyroid
glands help maintain the level of calcium in the body and are located around the
thyroid. studies of people
receiving x-ray treatments to the head and neck have demonstrated a higher rate of hyperparathyroidism
than expected. Further, those people who had hyperparathyroidism and a history of
radiation treatments also had a greater frequency of thyroid disease than those who had
hyperparathyroidism but did not have radiation treatments.13 Radioactive iodine in the thyroid
exposes the parathyroid which may cause tumors in the parathyroid glands. The Hanford thyroid disease study is
investigating whether hyperparathyroidism is increased among people exposed to
hanford's radioactive releases.
Other Radiation Health
Effects
Although cancer is the most studied of all radiation health effects, exposure to
radiation can harm the human body in other ways. The following are brief summaries of
some other radiation health effects. Publications are available from the network on some
of these health effects.
Immune System
The immune system is a complex network in the body that helps fight diseases
and foreign substances. Studies have shown that radiation exposure can weaken the
immune system. Autoimmune diseases are those in which a person's own
immune system attacks one or more tissues or organs. These diseases include multiple
sclerosis and lupus. While there have not been any studies concerning hanford and
autoimmune diseases, some Hanford-area residents are concerned that their exposure to
radioactive materials has triggered such diseases. They believe that there are a higher
than normal number of autoimmune disease cases among those who were exposed. For
more information on the immune system and radiation's effects on it, see Immune System and Radiation.
Genetic Effects and Birth
Defects
Genetic
effects of radiation exposure occur when radiation damage to a parent's DNA
code is transmitted to a child. (The DNA code contains information required for the
development and maintenance of all organisms.) Genetic effects caused by radiation fall
into two categories: For more information about these health effects, see HHIN'S genetic effects and birth defects from radiation exposure.
This publication includes a summary of a birth defects study of children born in the
hanford area. The study found an increase in one kind of birth defects, neural tube defects.
but the study's scientists did not attribute this increase to hanford radiation exposure.
Nervous System
Other Effects on the Lives of
Those who were Exposed
The secrecy surrounding the hanford releases, the involuntary nature of the
exposure and the lack of information about radiation health effects have left some people
understandably frustrated, mistrustful and angry. Many people report feeling that the
emotional and economic toll has been great. This is especially true for those who have thyroid diseases and other illnesses
and whose family members, friends and neighbors are ill or have died. For additional
reading on these aspects, see HHIN"S Coping with
Uncertainty and Illness: Concerns of Hanford Downwinders.
Many callers to the hanford health information lines have reported concerns
about their health. Scientific research has not - or at least not yet - related health
problems to exposure to radiation released from hanford. however, some DOWNWINDERS
do have health problems and believe that these problems are related to hanford. The
following personal perspective is offered to help readers understand these experiences
and concerns.
"When I arrived in Richland in 1954, I was healthy, happy, full of energy and a
bride of two weeks. It wasn't long before I began having horrific migraines, and
unexplained attacks of vomiting and diarrhea that sent me to the hospital because I was
dehydrated. tests could not explain my symptoms - yet they persisted. I was weak to the
point of exhaustion. And I lost an alarming amount of weight.
Within a few years it became impossible for me to participate in family and social
events. More often than not, I stayed home and on more than one occasion, my husband
and children went on vacation trips without me. Two of my pregnancies ended in
miscarriages. By my early 30s, i was a semi-invalid. I was diagnosed with endometriosis
(growth of uterine tissue outside the uterus). When I was 35, I was rushed to the hospital
unconscious and hemorrhaging. An emergency hysterectomy saved my life. Seven years
ago, I was diagnosed with fibromyalgia. Was it connected to living there (near Hanford)?
the doctors didn't connect it - yet?
Both of our children were born with immune dysfunctions. A simple cold was an
alarming matter. They were often anemic and our pediatrician tested them for Leukemia.
both had skin cancer. My adult daughter has endometriosis. Connected? I wonder...
Without warning, my husband was diagnosed with prostate cancer. It had
already metastasized to his kidney, then to his liver. he died in 1990. His question was,
"are our medical problems because we lived in Richland for 25 years?" It weighs heavily
upon my heart. Is there a connection? Studies and medical monitoring may one day
answer his question. We greatly miss his loving presence in our lives."
- name withheld by request. notes 1 - for further reading about hanford,
secrecy and
deception, see Atomic Harvest: Hanford and the lethal toll of america's nuclear arsenal
by Michael D'Antonio (crown pub. 1993); The Dragon's Tail: Radiation Safety in the
Manhattan Project, 1942-1946 by Barton C. Hacker (University of California 1987); On the
Home Front: The Cold War Legacy of the Hanford Nuclear Site by Michele Stenehjem
gerber (University of Nebraska 1992); and Sordid Sorcery: The History of Hanford's
Deception by The Hanford Education Action League (HEAL 1992).
2 - National Research Council (BEIR V). Health effects of exposure to
low levels of ionizing radiation. National Academy Press, 1990. BEIR V was a
committee of 17 scientists from the National Academy of Sciences. The chair of BEIR V
was Arthur C. Upton.
3 - BEIR V, p. 162.
4 - T. Straume, et al. "Neutron Discrepancies in the DS86 Hiroshima
Dosimetry System." Health Physics, October 1992, vol. 63, no. 4, pp. 421-426. in 1992,
Straume was with Lawrence Livermore National Laboratory. His colleagues were from
SAIC in San Diego, the University of Rochester (N.Y.) and Hiroshima University.
5 - J.W. Gofman. Radiation-Induced Cancer from Low-Dose Exposure:
An independent analysis. Committee for Nuclear Responsibility, 1990, chapter 25, p. 15.
Gofman is professor Emeritus of Molecular and Cellular Biology at the University of
California, Berkeley.
6 - R.H. Nussbaum and Wolfgang Kohnlein. "Inconsistencies and open
questions regarding low-dose health effects of ionizing radiation." Environmental
health perspectives, vol. 102, no. 8, August 1994, pp. 656-667. Nussbaum is professor
Emeritus of Physics and Environmental Sciences at Portland (OR.) State University.
Kohnlein is professor and director of the Institute for Radiation Biology at the University of
Munster in Germany. see also "Health Consequences of Exposures to Ionizing Radiation
from External and Internal Sources: Challenges to radiation protection standards and
biomedical research," medicine and global survival, vol. 2, no. 4, December 1995, pp.
198-213.
7 - R.A. Kerber, et al. "A Cohort Study of Thyroid Disease in Relation to
Fallout from Nuclear Weapons Testing." Journal of the American Medical Association,
vol. 270, no. 17, November 3, 1993, p. 2082.
8 - V.A. Stsjazhko, et al. "Childhood Thyroid Cancer since accident at
Chernobyl" (letter). British Medical Journal, vol. 310, march 25, 1995, p. 801.
9 - table is adapted from V.A. Stsjazhko, et al. "Childhood Thyroid
Cancer since accident at Chernobyl" (letter). British Medical Journal, vol. 310, March 25,
1995, p. 801.
10 - Technical Steering Panel of the Hanford Environmental Dose
Reconstruction Project. Representative Hanford Radiation Dose Estimates, revision 1.
April 21, 1994, p. 2.
11 - M. Balter. "Children become the
first victims of fallout." Science,
vol. 272, April 19, 1996, p. 359.
12 - E. Ron, J. Lubin, and A.B. Schneider. "Thyroid Cancer Incidence."
nature, vol. 360, November 12, 1992, p. 113. Ron and Lubin are with the Epidemiology
and Biostatistics program at the National Cancer Institute. Schneider is with Humana and
Michael Reese Hospitals at the University of Illinois.
13 - A. Katz and G.D. Braunstein. "clinical, biochemical, and
pathologic features of radiation-associated hyperpara-thyroidism." archives of internal
medicine, vol. 143, January 1983, pp. 79-82.
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Are My Health Problems Caused
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This is one of the most-often-asked questions when people call the Hanford Health Information Network (HHIN). Many people exposed to the radioactive releases from Hanford want to know if this exposure caused their health problems. Some people who were exposed have developed cancers and other diseases.
Why the "Cause" Is Hard To Know
There are several reasons why it is hard to know if Hanford's releases were the cause of a person's health problems. One reason is that a number of factors may be involved in producing a disease. Another reason is that there are no tests or measurements that show past exposures to radiation.
Another Way To Look at the Question of What Caused Health Problems
Medical scientists respond to this question in terms of risk. Risk is the likelihood of getting a disease. Many scientists and public health officials believe that any radiation dose could increase the risk for cancer and possibly other health problems. (Dose is the amount of radiation absorbed by a part of the body.) Having an increased risk does not always lead to developing a disease. Having an increased risk means that the chances of getting a disease are higher than if the exposure had not occurred.
Hanford Doses and Risk
Two studies focus on radiation doses from Hanford and the risk of health effects.
The Hanford Environmental Dose Reconstruction (HEDR) Project sought to find out the amount and types of radioactive materials Hanford released between 1944 and 1972, and how people were exposed. HEDR also provided estimates of the range of radiation doses people may have received. The HEDR Project found that Hanford released more than 200 kinds of radioactive elements (radionuclides). The study concluded that a radioactive form of iodine, iodine-131, accounted for more than 98 percent of the radiation dose that most people received outside the Hanford site.
The Hanford Thyroid Disease Study (HTDS) is a health study. Its purpose is to investigate whether thyroid disease is related to levels of estimated radiation dose among persons exposed as children to Hanford's air releases of iodine-131 during the 1940s and 1950s. The Fred Hutchinson Cancer Research Center conducted the research. CDC sponsors the study.
For the NAS report, visit http://www.national-academies.org
Published March 2000
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Important Notice: The Hanford Health Information Network (HHIN) closed in May, 2000. HHIN Web pages are provided as archived information only, and are not currently maintained. Information contained on the HHIN Web pages may be out-of-date. All HHIN publications are available.
Production of plutonium at the Hanford Site released many radioactive substances into the environment for more than 40 years. This publication discusses the way that exposure to radiation occurs, how the body handles internal radiation exposure, and which tissues and organs received most of the dose from the radioactive materials released from Hanford. Dose is the amount of radiation, or energy, absorbed by the body.
HANFORD'S RADIOACTIVE RELEASES
In producing plutonium, Hanford released radioactive materials into the air and the Columbia River. Much of the information about the radiation released from Hanford comes from the
The HEDR Project estimated that six radioactive materials released into the air account for nearly all the radiation dose a person may have received from the air
pathway. The Project also estimated that five substances account for most of the dose a person may have received from the
water pathway. (The air and water pathways are the key ways in which people received radiation exposure.) These 11 substances are listed in the tables later in this publication. The HEDR Project also calculated dose estimates for representative (typical) individuals. The Project's Technical Steering Panel published the summary results and representative dose estimates in April 1994.
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| Radioactive substances released to the air for which doses are being estimated by the Dose Reconstruction Project. | ||||
| Substance | Amount Released from Hanford |
Main Routes of Exposure |
Organs Receiving Main Dose |
Half-life |
| Iodine-131 | 762,000 curies* | ingestion | thyroid | 8 days |
| Ruthenium-103 | 1,160 curies | external inhalation |
whole body lungs |
39.4 days |
| Ruthenium-106 | 388 curies | inhalation ingestion |
lungs GI tract |
368 days |
| Strontium-90 | 64.3 curies | ingestion | bone surfaces
red bone marrow |
28.8 years |
| Plutonium-239 | 1.78 curies | inhalation | lungs bone surfaces |
24,100 years |
| Cerium-144 | 3,770 curies | inhalation ingestion |
lungs GI tract |
284 days |
*For comparison: The Three Mile island nuclear power plant accident in 1979 released between 16 and 24 curies of iodine-131. The 1986 accident at the Chernobyl plant released between 35 million and 49 million curies of iodine-131. The nuclear bomb fallout from aboveground tests at the Nevada test Site (1951-1970) released approximately 150 million curies of iodine-131.
Note: Scientific experts for lawsuits against Hanford contractors have estimated that Hanford's iodine 131 releases were higher (900,000 curies) than the HEDR estimate shown above.
| Radioactive substances released to the Columbia River for which doses are being estimated by the Dose Reconstruction Project. | ||||
| Substance | Amount Released from Hanford (as estimated by the HEDR Project)* | Main Routes of Exposure |
Organs Receiving Main Dose |
Half-life |
| Phosphorus-32 | 229,000 curies | ingestion | red bone marrow | 14.3 days |
| Zinc-65 | 491,000 curies | ingestion | whole body | 245 days |
| Arsenic-76 | 2,520,000 curies | ingestion | GI tract stomach for infants |
26.3 hours |
| Sodium-24 | 12,600,000 curies | ingestion | stomach | 15 hours |
| Neptunium-239 | 6,310,000 curies | ingestion | GI tract | 2.4 days |
*From a 1994 HEDR Project report (Heeb, PNWD-2223 HEDR, January 1994).
FOR MORE INFORMATION
This information sheet serves as an introduction to the topic of how certain radioactive substances released from hanford are handled by the body. Other network publications can provide further information:
The Release of Radioactive Materials from Hanford: 1944-1972 provides more detailed information about Hanford's radioactive releases.
An Overview of Hanford and Radiation Health Effects offers a brief history of Hanford's releases and information on the potential health effects of radiation.
Potential Health Problems from Exposure to Selected Radionuclides: Plutonium, Strontium, Cerium and Ruthenium discusses four radionuclides Hanford released to the air.
Radionuclides in the Columbia River: Possible Health Problems in Humans and Effects on Fish discusses five radio-nuclides Hanford released to the river.
Heeb, C. M. Radionuclide Releases to the Atmosphere from Hanford Operations, 1944-1972. PNWD-2222 HEDR, January 1994.
Heeb, C. M. and D. J. Bates. Radionuclide Releases to the Columbia River from Hanford Operations, 1944-1971. PNWD-2223 HEDR, January 1994.
Phipps, A.W., G.W. Kendall, J.W. Stather, and T.P. Fell. Committed Equivalent Organ Doses and Committed Effective Doses from Intakes of Radionuclides. National Radiological Protection Board of the United Kingdom, NPRB-R245, 1991.
Roessler, Genevieve. "Radiation Dose," Radiation Dose Newsletter by the Technical Steering Panel of the Hanford Environmental Dose Reconstruction Project. Oct. 1993.
Till, John and H. Robert Meyers, ed. Radiological Assessment: A Textbook on
Environmental Dose Analysis. Washington, D.C.: U.S. Government Printing Office,
1983.
Published Spring 2000
| A PUBLICATION OF THE Hanford Health Information Network |
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| HERE YOU'LL FIND... |
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Introduction
Ernest Sternglass: Radiation Relatively More Harmful at Low Levels Alice Stewart: Total Risk of Radiation Exposure Underestimated |
Introduction
This publication discusses the question of whether there is an increased risk for developing cancer among people who were exposed to radiation released from Hanford. It offers the opinions of three scientists: Drs. Ernest J. Sternglass, Alice M. Stewart and Gregg S. Wilkinson. Their essays follow in alphabetical order.
In your opinion, what kind of dose range from Hanford could have posed a public health risk by causing cancer?
Comment specifically on the various nuclides for which doses will be calculated by the Hanford Environmental Dose Reconstruction Project.
Each scientist has approved the edited version of their essay and selected
references follow each piece. A complete bibliography of all the references used by the
three scientists is available from the Network.
ERNEST J. STERNGLASS, Ph.D. has been Professor Emeritus of Radiology at the University of Pittsburgh's School of Medicine since 1983. He has held professorships in radiology and physics at several universities, including Stanford, Indiana University, and the Institute Henri Poincare in Paris, France. Dr. Sternglass was the Director of the Apollo Lunar Scientific Station Program while at Westinghouse Research Laboratories. His doctorate in Engineering Physics (1953) comes from Cornell University, as does his post-graduate and undergraduate degrees in Engineering Physics and Electrical Engineering, respectively. He taught physics at George Washington University and held a research fellowship at Cornell University. Dr. Sternglass has received many academic and professional honors, is a member of several professional societies and holds 13 patents. He is the author of several books on low-level radiation.
Exposure to radioactive substances, such as those released from Hanford, increases the risk of cancer. There is increasing evidence that the risk of cancer is proportionately greater at low doses. These low doses are only a thousandth of the dose levels of the Japanese atomic bomb survivors. The atomic bombs exposed the Japanese to short bursts of external radiation.
Internal radiation doses from contaminated food and water over a long time appear to damage the body much more than the same doses from short external exposures, such as X-rays. Around Hanford, people received internal exposure over a long time.
Highly toxic forms of oxygen, called free radicals, can increase the harmfulness of radiation exposure. The power of free radicals to do harm increases as the dose levels decrease. The lower the dose per year, the higher the risk. The increasing harmfulness of free radicals has been found down to levels of 20-200 millirem per year. This level of exposure is equal to the amount received from background radiation.
This evidence shows that constant, low levels of radiation are relatively more harmful than higher levels of exposure over a short time. This is especially important for people who were exposed to the radiation releases from Hanford.
Selected References
Gould, J.M., E.J. Sternglass, "Nuclear Fallout, Low Birthweight, and Immune Deficiency." International Journal of Health Services: 1994; 24 (2): 311-335.
Mangano, J.J. "Cancer Mortality Near Oak Ridge, Tennessee." International
Journal of Health Services: 1994; 24 (3).
ALICE M. STEWART, M.D., has been a Senior Research Fellow at Birmingham University in England since 1974, where her work continues on the Oxford Survey of Childhood Cancers. This study began over 30 years ago while she was pursuing her career in scientific research in social medicine at Oxford University. Her epidemiological findings while at Oxford linked the use of pre-natal X-rays to childhood leukemias. She continues to speak out against the risks of low-dose radiation exposure to workers in the nuclear industry. Dr. Stewart was a founding member of both the International Epidemiological Society and the Society for Medicine. She received her medical degree from Cambridge University in 1932 and was the youngest woman to be elected to the British Royal College of Physicians before 1947. She continues to study the health of workers in U.S. nuclear weapons facilities.
Exposure to radiation can harm the immune system. A weakened immune system can result in an exposed person catching an infection and possibly dying from it or any infection-related cause of death. Such a person might also have developed a cancer from the radiation exposure. But because the person died from another illness first, the cancer did not have time to fully develop and be diagnosed. By not accounting for deaths from weakened immune systems, current risks of cancer deaths from radiation exposure underestimate the harmfulness of radiation.
It is unlikely that the harmfulness of radiation is reduced at low-dose levels. Rather, it is possible that the mutations to cells caused by repeated and unavoidable exposures to background radiation are the most common cause of cancer. In addition, a large British study of childhood cancer deaths (Oxford Survey of Childhood Cancers) has found many reasons why detection of cancers caused by constant low-level radiation is always a complex problem.
According to data from the Oxford Survey, childhood cancers include a relatively large number of embryomas, cancers of the embryo. These may be the result of exposure while in the womb to background radiation, as well as medical X-rays. Furthermore, for all cancers that began in the womb, there was evidence of mounting sensitivity to infections while the cancers were growing. Consequently, deaths during the latency period (the time it takes for cancers to develop) of a childhood cancer are common. The latency period deaths also result in falsely low rates of leukemia and lymphoma for children who have survived high rates of infant mortality. Leukemia and lymphoma are cancers of white blood cells.
Besides causing early cancer deaths, infections can also shorten the latency period. In countries with low rates of infant mortality, cases of leukemia and lymphoma are relatively common. However, these cases are distributed unevenly: there are higher rates in rural areas and in people who are well-to-do.
According to the Oxford Survey, immunizations against infectious diseases have reduced the risk of an early cancer death. However, African children who live in areas of holoendemic malaria and have survived a high risk of dying during infancy rarely develop leukemia. Therefore, it is possible that, even in children, the spread of cancer cells can be prevented by immune system reactions to the dangerous situations created by the malarial parasite. Based on this evidence, the number of cancers depends less upon the level of exposure to background radiation than upon the nature and intensity of indigenous infections. In addition, the number of cancers depends on such things as levels of family income, population density and the availability of immunizations.
The only measurable effect of the Hanford releases could be the one caused by the releases of iodine-131. By its effect on the thyroid gland, these releases would increase the risk of cancers that are normally rare. Thyroid cancers accounted for only three of the 22,351 cancers eventually included in the Oxford Survey. Therefore, even a single case of thyroid cancer among persons exposed (in the womb or as young children) to the iodine releases from Hanford would be a highly suspicious finding.
Evidence of a special association between radioactive iodine and thyroid cancers has already been obtained from Marshall Islanders and Ukrainian children. Therefore, I recommend that a study identify all live births for the period of 1944-1955 in the regions covered by the Hanford Environmental Dose Reconstruction Project, as well as all cancer deaths in this population. This relatively simple procedure would detect any thyroid cancer effect of the reconstructed doses. Remember, even one case of thyroid cancer would be highly suspicious. Comparing the thyroid cancer effect to other populations and other cancers could be done to estimate the overall effect of all the Hanford releases.
Selected References
Bithell, J.F., A.M. Stewart, "Pre-Natal Irradiation and Childhood Malignancy: A Review of British Data from the Oxford Survey." British Journal of Cancer: 1975; 31: 271-287.
Gilman, E.A., G.W. Kneale, E.G. Knox, A.M. Stewart, "Pregnancy X-rays and Childhood Cancers: Effects of Exposure Age and Radiation Dose." Journal of the Society for Radiological Protection: 1988; 8 (1): 3-8.
Kneale, G.W., A.M. Stewart, L.M. Kinnier Wilson, "Immunizations Against Infectious Diseases and Childhood Cancers." Cancer Immunology and Immunotherapy: 1986; 21: 129-132.
Stewart, A.M., G.W. Kneale, "The Immune System and Cancers of Fetal Origin." Cancer Immunology and Immunotherapy: 1982; 14: 110-116.
Stewart, A.M., J. Webb, D. Giles, D. Hewitt, "Malignant Diseases in Childhood and
Diagnostic Irradiation In Utero." The Lancet: 1956; ii: 447.
Gregg S. Wilkinson, M.A., Ph.D. is a Professor of Epidemiology in the Department of Preventive Medicine and Community Health, and Director of the Division of Epidemiology and Biostatistics at the University of Texas Medical Branch (UTMB) in Galveston, Texas. Prior to joining the faculty at UTMB, Dr. Wilkinson was an Associate Epidemiologist with Epidemiology Resources, Inc., and he also served as the Principal Investigator for the nationwide study of U.S. plutonium workers at the Los Alamos National Laboratory. He received his doctorate in 1973 from the State University of New York at Buffalo and held a post-doctoral fellowship at Duke University Medical Center. In addition to his research concerning low- dose effects from ionizing radiation, Dr. Wilkinson's research interests include the epidemiology of neural tube and other birth defects, environmental and occupational epidemiology and epidemiological methods.
At what levels of exposure to radioactive materials is there an increased risk of cancer? Two factors must be known before that question can be answered. First, information on exposures (or doses) to individual members of the population under consideration must be calculated. Second, health problems that the population experienced after the exposure must be identified. From this information, a risk estimate can be made.
Regarding the list of radioactive materials for which doses are being calculated, I am limiting my comments to the radioactive elements with which I have some experience: plutonium-239 and iodine-131.
Plutonium-239
Plutonium causes cancer in animals. One human study suggested that Rocky Flats workers who had plutonium uptakes of more than two nanocuries had increased risks of dying (Wilkinson 1987). A similar study of Hanford workers, however, found no increased risks (Gilbert 1989). Unfortunately, the Hanford study had little chance of detecting anything other than huge increases in risk. This was due to the relatively small number of exposed workers and the skewed nature of the exposures. There were few workers with recorded body burdens greater than 5% of the maximum permissible body burden (2 nanocuries). The U.S. Department of Energy sets the standard for the maximum permissible body burden at 40 nanocuries of plutonium.
Generally, workers experience higher exposures to plutonium than the public. Thus, doses for the population exposed to the Hanford releases are probably not high enough to result in detectable increases in disease rates. This does not mean that there is no increase in risk. Rather, it is very difficult to detect anything other than very large increases in risk. This is due to the limitations of existing information and the methods that epidemiologists have available to them.
Most studies that have measured plutonium uptake by the potentially exposed public have been inconclusive or have not found increased levels of plutonium in human tissues that could be attributed to the operations of weapons facilities (Cobb 1982, Nelson 1993). Unfortunately, in recent years the emphasis of programs that were monitoring the amount of plutonium taken up by the public and by workers has shifted almost exclusively to only monitoring nuclear workers (Nelson 1993).
Iodine-131
Potential risks associated with iodine-131 are a serious concern. Researchers have found an increased rate of thyroid growths in people who were exposed as children. Their doses were as low as nine rads (Ron 1989). The thyroid easily absorbs iodine-131 through the food chain. Scientists have recently identified an increased thyroid cancer incidence among people in Los Alamos County, New Mexico. No one has begun a comprehensive dose reconstruction at Los Alamos. The sustained high level of thyroid cancer in a population living near that nuclear weapons plant is cause for concern.
There is a low chance of dying from thyroid cancer because it can be successfully treated. Because of this, researchers should study cancer incidence rather than cancer deaths to determine if increased risks of thyroid cancer are present. A further complication in determining risk is that many tumor registries do not collect information on benign growths or other types of illnesses. Studies show that there is also an increase in benign growths among radiation-exposed individuals. Other thyroid abnormalities may be present. Thus, the sum of thyroid problems which may be due to iodine-131 exposure will be difficult to determine.
Conclusion
A valid estimate of the health risk posed by Hanford releases will require accurate individual dose estimates, accurate measures of disease incidence and at least a moderate number of affected individuals. Risk estimates may only be possible for thyroid disease from exposure to iodine-131. For other health problems and for other radioactive materials, valid estimates of disease rates and exposure levels are unlikely. Because exposures from Hanford are unique, comparisons with other exposures, other health problems or animal studies may be of limited value and often misleading.
Selected References
Cobb, J.C., B.C. Eversole, P.G. Archer, et al. "Plutonium Burdens in People Living Around the Rocky Flats Plant." Final Report submitted to Environmental Monitoring Systems Laboratory, U.S. Environmental Protection Agency, P.O. Box 15027, Las Vegas, NV 89114. June 1982.
Gilbert, E.S., G.R. Petersen, J.A. Buchanan, "Mortality of Workers at the Hanford Site: 1945-1981." Health Physics: 1989; 56:11-25.
Nelson, I.C., V.W. Thomas, R.L. Kathren, "Plutonium in South-Central Washington State Autopsy Tissue Samples: 1970-1975." Health Physics: 1993; 64 (4): 422-428.
Ron, E., B. Modan, D. Preston, et al. "Thyroid Neoplasia Following Low-Dose Radiation in Childhood." Radiation Research: 1989; 120: 516-531.
Wilkinson, G.S., G.L. Tietjen, L.D. Wiggs, et al. Mortality Among Plutonium and Other Radiation Workers at a Plutonium Weapons Facility. American Journal of Epidemiology: 1987; 125: 231-250.
Published Summer 1994
