Radiation Exposure

What do we really know about radiation, and the effects it has on the human body? 

First discovered in the 18th century, uranium is an element found everywhere on Earth, but mainly in trace quantities. In 1938, German physicists Otto Hahn and Fritz Strassmann showed that uranium could be split into parts to yield energy. Uranium is the principal fuel for nuclear reactors and the main raw material for nuclear weapons. (Institute for Energy and Environmental Research 2012)

Our understanding of individual radionuclides, radiation dose, and related health risk comes into fruition from decades of studying the fallout from nuclear weapons tests and x-rays. Researchers Steven Simon, André Bouville and Charles Land suggest that the data supports the notion that certain types of cancer develop as a result of the specific type of radiation exposure. The following is a statement from their feature article in the 2006 issue of American Scientist, Fallout from Nevada Weapons Tests and Cancer Risks,

“We estimate that in the U.S. the primary cancer risks from past exposure to radioactive fallout are thyroid cancer and leukemia, whereas in a very few cases—for example, the Marshall Islands—large internal doses as a result of ingestion of radionuclides have led to significant risks of cancers in the stomach and colon.” (Simon, Bouville, Land 06)

“Radioactivity” can be defined as the property of some atoms which causes them to spontaneously give off energy in the form of particles or rays (U.S. Environmental Protection Agency 2011). It appears that radioactivity and fallout have inspired more than just fear amongst our society. The science surrounding the effects of radioactive fallout in human biology is so complex because it incorporates so many areas of research. The high level scrutiny in this particular field of research also surrounds the concerns for the complexity; nuclear and radiation physics, chemistry, statistics, ecology, meteorology, genetics, cell biology, physiology, exposure and risk assessment, and epidemiology. (Simon, Bouville, Land 06)

Cancer investigators who specialize in radiation effects have, over the intervening decades, looked for another signature of nuclear testing—an increase in cancer rates. And although it is difficult to detect such a signal amid the large number of cancers arising from "natural" or "unknown" causes, we and others have found both direct and indirect evidence that radioactive debris dispersed in the atmosphere from testing has adversely affected public health. Frequently, however, there is misunderstanding about the type and magnitude of those effects. Thus today, with heightened fears about the possibilities of nuclear terrorism, it is worthwhile to review what we know about exposure to fallout and its associated cancer risks. (Simon, Bouville, Land 06)

Prior to 1980, nuclear weapon testing was being done while the public was still relatively unaware of the risks associated with radiation and fallout exposure. As the team of researchers explains in the article, by studying those populations exposed to radiation, like Hiroshima and Nagasaki bomb survivors, the data showed an increase in cancer risks.   

Nuclear testing…ended in 1980, in part because of public concerns about involuntary exposure to fallout. By that time, increased cancer risk had been established as the principal late health effect of radiation exposure, based primarily on studies of populations exposed to medical x rays, to radium and radon decay products from the manufacture of luminescent (radium) watch dials and in uranium mining, and to direct radiation from the atomic bombings of Hiroshima and Nagasaki. (Simon, Bouville, Land 06)

The United States Department of Energy showed another contributing factor which legitimized some of the fears being expressed by the public. In 1979, research was being carried out to estimate radiation doses in populations downwind of the Nevada Test Site. The following excerpt lists some of their findings and provides an example of their methodology from the American Scientist article,    

Doses from internal irradiation within this local fallout area were ascribed mainly to inhalation of radionuclides in the air and to ingestion of foodstuffs contaminated with radioactive materials. Doses from internal irradiation were, for most organs and tissues, substantially smaller than those from external irradiation, with the notable exception of the thyroid, for which estimated internal doses were substantially higher. Estimated thyroid doses were ascribed mainly to consumption of foodstuffs contaminated with iodine-131 (I-131) and, to a lesser extent, iodine-133 (I-133), and to inhalation of air contaminated with both I-131 and I-133. Thyroid doses varied according to local dairy practices and the extent to which milk was imported from less contaminated areas.  Bone-marrow doses less than 50 mGy were estimated for communities in a local fallout area within 300 kilometers of the NTS, where ground-monitoring data were available, and an order of magnitude less for other communities in Arizona, New Mexico, Nevada, Utah and portions of adjoining states. (Simon, Bouville, Land 06)

In the month of August in 1980, a detailed account was published on some of the effects that resulted from nuclear tests called, The Forgotten Guinea Pigs: A Report on Health Effects of Low-Level Radiation Sustained As a Result of the Nuclear Weapons Testing Program Conducted by the United States Government, prepared for the use of the Committee on Interstate and Foreign Commerce, United States House of Representatives, and its Subcommittee on Oversight and Investigations. This investigation focused on the nuclear weapons testing programs that ran from the 1940’s to the 1950’s. The impact of those initial findings gets reflected in the conclusion of the official report.  

Atmospheric testing of nuclear weapons in the 1950’s and 1960’s may well have been essential to secure the national defense. However, because the agency charged with developing nuclear weapons was more concerned with that goal than with its other mission of protecting the public from injury, the government totally failed to provide adequate protection for the residents of the area. There was sufficient information available from the beginning to suggest that if it was not possible to conduct the testing outside the continental United States, then the people living nearby needed protection. The necessary protection could have been provided by evaluating some of the people but, at a minimum, the government owed the residents a duty to inform them of the precise time and place of each test and to instruct them as to what precautions should be taken. In addition, the government’s program for monitoring the health effects of the tests was inadequate and, more disturbingly, all evidence suggesting that radiation was having harmful effects, be it on the sheep or the people, was not only disregarded but actually suppressed.

The greatest irony of our atmospheric nuclear testing program is that the only victims of U.S. nuclear arms since World War II have been our own people. (U.S. Congress, House, Committee on Interstate and Foreign Commerce, Subcommittee on Oversight and Investigations 1980)  

Many faults were found and listed in the actual testing processes which were then immediately followed by the implementation of safety procedures for future weapons testing. 

*The complete original report is available for download in a .pdf file at the Federal Depository Library Program website. 

In 1983, Congress enacted Public Law (97-414) directing the Department of Health and Human Services (DHHS) to open up an investigation, which was eventually delegated to the National Cancer Institute, into the potential risks of thyroid cancer from exposure to iodine-131 (I-131) due to the radioactive fallout from the atomic bomb tests held at the Nevada Test Site during the 1950s and early 1960s.

In 1990, Congress passed the Radiation Exposure Compensation Act (RECA). This represents an official government apology to the victims of America’s Cold War nuclear program. This piece of legislation also publicly acknowledges the United States’ failure to warn the workers in uranium mines, the on-site test victims, and the downwind communities exposed to fallout from atomic bomb tests. (U.S. Department of Justice 2008)

In 1997, the National Cancer Institute published their research findings in a two-volume report titled, Estimated Exposures and Thyroid Doses Received by the American People from Iodine-131 in Fallout Following Nevada Atmospheric Nuclear Bomb Tests. After the details were discovered, the United States Congress requested that the Department of Health and Human Services expand on their research. This would mean that in the future, investigations would have to include looking for other radionuclides in the fallout from weapons testing and consider testing outside of the United States to other regions of the country that may have potentially exposed people to significant amounts of radiation. (National Cancer Institute 1999) 

In 2003, thirteen years after those initial NCI estimates from I-131 weapons testing fallout: it released a new publication: Radioactive I-131 from Fallout, to public health care providers and advocacy groups, but still not to the general public. The official press release of the NCI Complete Nationwide study of Radioactive Fallout from 1950s Nuclear Tests, states the researchers discover,

“Depending on their age at the time of the tests, where they lived, and what foods they consumed, particularly milk, Americans were exposed to varying levels of I-131.” (National Institutes of Health 1997)

One of the major contributing factors that may have helped prompt the investigation surrounding nuclear fallout and children is also reflected in the subsequent line,   

“Since I-131 accumulates in the thyroid gland, concerns have been raised that the fallout could cause thyroid cancer in people who were exposed to it as children.” (National Institutes of Health 1997)

The Pacific Proving Ground program has provided a significant amount of data due to the level of fallout-related doses contaminating the Marshall Islands and its’ inhabitants.

“Many of the Marshall Islands remain contaminated by nuclear fallout and many of these survivors living during the time of the testing suffer increased incidence of several types of cancers and birth defects.”

The level of uncertainty surrounding the link between fallout and specific cancers was so high because the number of cancer cases involved was so small. For example, one way they handled the difficulties in correlating fallout levels with thyroid cancer rates was found in more collaborative efforts.

“To provide more accurate information on the risk of thyroid cancer from radioactive fallout, NCI investigators, in collaboration with other U.S. government agencies and international organizations, are watching with the government of scientists in Belarus and Ukraine to study thyroid cancer among children in those countries who were exposed to fallout of various isotopes of iodine, mainly I-131, from Chernobyl nuclear accident in 1986.” (National Institutes of Health 1997)

In 2006, the Institute for Energy and Environmental Research (IEER) released a report entitled, Science for the Vulnerable: Setting Radiation and Multiple Exposure Environmental Health Standards to Protect Those Most at Risk. The researchers’ findings lead them to conclude, 

“…federal radiation protection standards are dangerously skewed, thus ignoring the most vulnerable members of the American public.” (Makhijani, Smith, Thorne 2006)

Also featured in the reports, the following point gets made, 

“…society pays a great deal of attention the reproductive rights of a woman who does not want a child, but very little attention to the rights of women who want to be mothers of healthy babies.” (Makhijani, Smith, Thorne 2006)

The IEER also brings to light some problems with the federal safety standards, such as  the lack of group estimates other than what is called, “the reference man”, based on a 14 pound adult Caucasian male in his twenties (IEER 2012). This obviously would exclude children, an embryo or fetus, and women. All of which are often more sensitive to the harmful effects of radiation from fallout or toxic materials left from uranium mining. (Institute for Energy and Environmental Research 2012) So, the IEER researchers suggest that,

When considering the development of radiological protection standards, it is proper to bear in mind that variations in sensitivity will arise not only due to age and sex, but also due to exposure to toxic chemicals that will interact with radiation in complex and poorly understood ways. (Simon, Bouville, Land 2006)

Almost all radionuclides in fallout emit beta (electron) and gamma (photon) radiation. A cascade of events follows once tissue is exposed to radiation: As the initial radiation scatters, and atoms in the body are ionized by removal of weakly bound electrons. Radiation can damage DNA by direct interaction or by creating highly reactive chemical species that interact with DNA (Simon, Bouville, Land 06).

-How data was collected-

Doses from fallout received in the 1950s and 1960s have been estimated…using mathematical exposure assessment models and historical fallout deposition data.

The relatively large particles that tend to fall out first are not efficiently transferred to the human body. At more distant locations in the region of local fallout, internal dose is relatively more important because smaller particles that predominate there are biologically more available (Simon, Bouville, Land 2006).

Due to a lack of information on I-131 exposure specifically, a larger body of existing data is used from similar forms of research, such as studying medical x-rays. 

Relatively little of the information on radiation-related risk comes from studies of populations exposed mostly or only to radioactive fallout, because useful dose-response data are difficult to obtain. However, the type of radiation received from external sources in fallout is similar to medical x rays or to gamma rays received directly by the Hiroshima and Nagasaki A-bomb survivors, allowing information from individuals so exposed to be used to estimate fallout-related risks from external radiation sources (Simon, Bouville, Land 2006).

The criticisms of this particular research surround the small number of studies on persons exposed to I-131 from NTS fallout producing somewhat suggestive, but not conclusive evidence that it is linked to specific forms of cancer. 

Thyroid cancer is a rare disease overall—with U.S. lifetime rates estimated to be 0.97 percent in females and 0.36 percent in males—and it is extremely rare at ages younger than 25. Furthermore, the malignancy is usually indolent, may go long unobserved in the absence of special screening efforts and has a fatality rate of less than 10 percent. These factors make it difficult to study fallout-related thyroid cancer risk in all but the most heavily exposed populations. Thyroid cancer risks from external radiation are related to gender and to age at exposure, with by far the highest risks occurring among women exposed as young children. (Simon, Bouville, Land 2006)

The researchers acknowledge and factor in the noted criticisms of this issues research,   

However, observations of thyroid cancer risk among children exposed to fallout from the Chornobyl reactor accident in 1986 have led to a reassessment. An Institute of Medicine report concluded that the Chornobyl observations support the conclusion that I-131 has an equal effect, or at least two-thirds the effect of internal radiation. More recent data on thyroid cancer risk among persons in Belarus and Russia exposed as young children to Chornobyl fallout offer further support of this inference. (Simon, Bouville, Land 2006) 

The IEER website features a Brief Fact Sheet on Iodine-131 and Nevada Test Site Fallout, showing that NCI estimates the releases from the Nevada tests were up to 130 million curies, compared to the Chernobyl reactor incident, which was estimated to be around 7.3 million curies. (Institute for Energy and Environmental Research 1997)

The applicability of risk estimates based on studies of external radiation exposure to a population exposed mainly to internal sources, and to I-131 in particular, has been debated for many years. This uncertainty relates to the uneven distribution of I-131 radiation dose within the thyroid gland and its protraction over time. Until recently, the scientific consensus had been that I-131 is probably somewhat less effective than external radiation as a cause of thyroid cancer…(Simon, Bouville, Land 2006)

References:

Epstein, Samuel S. 2003. U. S. National Cancer Institute (NCI) Withheld Atom-Bomb Test Data. Cancer Prevention Coalition. Available online at

http://www.preventcancer.com/losing/nci/nci_atom_bomb.htm.

Epstein, Samuel S. 2003. Stop Cancer Before it Starts: How to Win the War on Cancer. Cancer Prevention Coalition. Available online at http://www.preventcancer.com/press/pdfs/Stop_Cancer_Book.pdf.

Institute for Energy and Environmental Research. 1997. Brief Fact Sheet on Iodine-131 and Nevada Test Site Fallout. (October). Available online at http://www.ieer.org/latest/i131info.html.

Institute for Energy and Environmental Research. 2007. Healthy from the Start / Tritium (Vol. 14, No. 4). (February 5). Available online at http://ieer.org/wp/wp-content/uploads/2012/01/SDA-14-4.pdf.

Institute for Energy and Environmental Research. 2012. Uranium: Its Uses and Hazards. Last modified (May). Available online at http://ieer.org/resource/factsheets/uranium-its-uses-and-hazards/.

Makhijani, Arjun, Brice Smith, and Michael C. Thorne. 2006. Science for the Vulnerable: Setting Radiation and Multiple Exposure Standards. Institute for Energy and Environmental Research. (October 19). Available online at http://ieer.org/resource/reports/science-vulnerable-setting-radiation/.

National Cancer Institute. 1999. Estimated Exposures and Thyroid Doses Received by the American People from Iodine-131 in Fallout Following Nevada Atmospheric Nuclear Bomb Tests. The National Cancer Institute at the National Institute of Health. Available online at http://www.cancer.gov/i131/fallout/contents.html.

National Institutes of Health. 1997. NIH Press Release: NCI Completes Nationwide Study of Radioactive Fallout from 1950s Nuclear Tests. National Institutes of Health. (July 25). Available online at http://www.nih.gov/news/pr/jul97/nci-25.htm.

Simon, Steven, André Bouville, and Charles Land. 2006. Fallout from Nuclear Weapons Tests and Cancer Risks. American Scientist. Available online at http://www.americanscientist.org/issues/issue.aspx?id=982&y=2006&no=1&content=true&page=5&css=print.

U.S. Congress, House, Committee on Interstate and Foreign Commerce, Subcommittee on Oversight and Investigations. 1980. "The Forgotten Guinea Pigs": A Report on Health Effects of Low-Level Radiation Sustained as a Result of the Nuclear Weapons Testing Program Conducted by the United States Government. The Federal Depository Library Program at Cal. Available online at http://www.lib.berkeley.edu/doemoff/govinfo/federal/fdlpexhibit/The_Forgotten_Guinea_Pigs.pdf.

U.S. Department of Justice. 2007. Radiation Exposure Compensation Act (RECA). Available online at http://www.justice.gov/civil/common/reca.html.

U.S. Environmental Protection Agency. 2011. Radiation and Radioactivity. (Last updated July 08). Available online at  http://www.epa.gov/rpdweb00/understand/radiation_radioactivity.html#radioactivity.