HANFORD DOWNWINDERS WERE KEPT IN THE DARK!

Unresolved Issues Concerning Hanford's Hot Particles

During the preparation of this report, the technical reviewers raised several important points that should be included.

Karl Z. Morgan, Ph.D., expressed great skepticism with the estimate for the amount of plutonium released from Hanford. The current estimate from the Hanford Environmental Dose Reconstruction Project is 1.78 curies of plutonium released to the air. Based upon his experience at the Oak Ridge (Tennessee) nuclear weapons facility and his knowledge of Hanford processes, Morgan believes that the current estimate is "a gross underestimate." Morgan is regarded by many as the father of health physics and was chief of radiation protection at Oak Ridge. He was chairman of the Internal Dose Committees of both the International Commission on Radiological Protection (ICRP) and the National Committee for Radiation Protection (NCRP) from 1949 to 1971. These committees set the maximum permissible radiation exposure limits on the international and national level, respectively.

Professor Ronald L. Kathren felt it was important to state that, given the current low radiation dose estimates from the selected radionuclides, it is "extremely unlikely" that there will be any measurable health problems among those exposed to Hanford's radiation releases. "Measurable health problem" means an effect that could be determined by an epidemiological study as being related to exposure from Hanford's radiation. Kathren is the director of the United States Transuranium and Uranium Registries and a professor at Washington State University.

Tim Connor stated that the assumption by the Hanford Environmental Dose Reconstruction Project that all of the plutonium released by Hanford to the air was in a soluble form is tenuous at best. Connor is concerned that even if the plutonium separated at Hanford was initially dissolved by nitric acid, further steps in the separation process would have resulted in transforming at least some of the soluble plutonium to an insoluble form. Thus, a considerable fraction of plutonium escaping to the atmosphere may have been in an insoluble form. Connor is a researcher with the Energy Research Foundation in South Carolina and was a staff member of the Hanford Education Action League (HEAL) for several years.

Summary

While comparisons to specific individuals are often uncertain, the information in this report may help identify potential health problems from exposure to Hanford's releases of plutonium, cerium, strontium and ruthenium. An important point to recall is that the estimates of the amounts released and the doses received are not yet complete.

The Technical Steering Panel completed its role in 1995. The federal Centers for Disease Control and Prevention (CDC) is now working with the HEDR Task Completion Working Group to continue public participation and to assure completion of the remaining HEDR activities.

References for the History of Hanford's Hot Particles

Stohr, Joe. Memo to the Technical Steering Panel and the Centers for Disease Control: "Preliminary Review of Documents Describing Hanford Particulate Releases, 1944-1954." December 26, 1990.

Thomas, Jim. Hanford Education Action League (HEAL) Memo to the Technical Steering Panel: "Request for Independent Calculations on the Active Particle Problem." April 20, 1992.

Till, John, Ph.D., and Charles Miller, Ph.D. Memo to the Technical Steering Panel: "Active Particle Problem at Hanford." Undated.

U.S. Senate, Majority Staff of the Committee on Governmental Affairs. "Early Health Problems of the U.S. Nuclear Weapons Industry and Their Implications for Today." December 1989.

NOTES

1 - HW-11348. "Action Taken with Respect to Apparent Enhanced Active Particle Hazard." H.M. Parker. October 25, 1948; p.2.

2 - HW-11348, p.2.

3 - "Early Health Problems of the U.S. Nuclear Weapons Industry and Their Implications for Today." Report of the Majority Staff of the Committee on Governmental Affairs, U.S. Senate, December 1989; p. 9 - Referring to meeting notes from the Advisory Committee for Biology and Medicine, Jan. 12, 1951.

4 - Telephone conversation with Bruce Napier, June 13, 1994. Napier is a scientist with Battelle Pacific Northwest Laboratory and worked extensively on the Hanford Environmental Dose Reconstruction Project.

5 - There have been human plutonium studies by several groups of researchers. Three of these are: George L. Voelz, Occupational Medicine Group, Los Alamos National Laboratory, et al. who studied 26 Manhattan Project workers at Los Alamos with 37-year follow-up after exposure (Voelz 1985); J. F. Acquavella et al. who also considered Los Alamos workers (Acquavella 1983); and Gregg S. Wilkinson et al. who studied Rocky Flats workers (Wilkinson 1987)

6 - H. Metivier in Radionuclide Metabolism and Toxicity; Galle, P. and R. Masse (eds.); Paris: Masson, 1982; p. 184. The book is a compilation of papers presented at a 1982 symposium that was organized by the French Society of Biophysics and Nuclear Medicine and the University of Paris.

7 - Gregg Wilkinson, Ph.D. "Mortality Among Plutonium and Other Radiation Workers at a Plutonium Weapons Facility." American Journal of Epidemiology. 1987; p. 231-250.

8 - Committee on the Biological Effects of Ionizing Radiations (BEIR IV); Health Risks of Radon and Other Internally Deposited Alpha-Emitters; Washington, DC: National Academy Press, 1988; p. 328.

9 - Telephone conversation with Prof. Ronald Kathren, U.S. Uranium and Transuranium Registries, July 22, 1994..

10 - George L. Voelz, MD. "Health Considerations for Workers Exposed to Plutonium." Occupational Medicine: State of the Art Reviews. Oct-Dec 1991; p. 694.

11 - H. Metivier in Galle and Masse, p. 193.

12 - BEIR IV, p. 325.

13 - Tawn, E.J. et al. "Chromosome Studies in Plutonium Workers." International Journal on Radiation Biology and Related Studies in Physics, Chemistry and Medicine, May 1985; p. 599-610.

14 - M.C. Thorne and J. Vennart; "The Toxicity of Sr-90, Ra-226 and Pu-239." Nature; October 14, 1976; p. 555-8. Thorne is with the Radiobiology Unit in Hardwell, England.

15 - M. Thomasset. "Strontium: Metabolism and Toxicity of Strontium" in Galle and Masse, p. 104.

16 - M. Thomasset in Galle and Masse, p. 111.

17 - National Committee on Radiation Protection (NCRP) No. 110; Some Aspects of Strontium Radiobiology; 1991; p. 32.

18 - M. Thomasset. "Strontium: Metabolism and Toxicity of Strontium" in Galle and Masse, p. 110.

19 - Telephone conversation with Bruce Napier, June 13, 1994.

20 - National Committee on Radiation Protection (NCRP) No. 60; Physical, Chemical, and Biological Properties of Radiocerium Relevant to Radiation Protection Guidelines; 1978; p. 55.

21 - R. Masse, "Ruthenium and Activated Metals" in Galle and Masse, p. 131-142.

References for Selected Radionuclides

Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Plutonium, TP-90-21. December 1990.

Galle, P. and R. Masse, eds. Radionuclide, Metabolism and Toxicity. Paris: Masson, 1982.

NCRP Report No. 60. Physical, Chemical, and Biological Properties of Radiocerium Relevant to Radiation Protection Guidelines. Washington, DC: National Council on Radiation Protection and Measurements, 1978.

NCRP Report No. 110. Some Aspects of Strontium Radiobiology. Bethesda, MD: National Council on Radiation Protection and Measurements, 1991.

Published Fall 1994

A PUBLICATION OF THE Hanford Health Information Network

Possible Health Problems in Humans and Effects on Fish

HERE YOU'LL FIND...

How Hanford Radiation Polluted the Columbia How People Were Exposed to Radiation from Hanford Hanford and Columbia River Fish Downwinder Perspective Hanford Dose Estimates Possible Health Problems Summary Unresolved Issues Notes

For more than 40 years, the U.S. government produced plutonium for nuclear weapons at the Hanford Site in south central Washington state. During that time, Hanford released radioactive elements and other materials into the Columbia River. (See map below.) From World War II until the early 1970s, the Columbia River downstream from Hanford "held the distinction of being the most radioactive river in the United States."¹ Many people now wonder what the potential health effects might be from exposure to these materials. There is also concern about the effects of these releases on the fish population and whether eating contaminated fish increased the risk of adverse health effects in humans.

Hanford also released other radionuclides to the air. According to the Technical Steering Panel (which directs the Hanford Environmental Dose Reconstruction Project),² iodine-131 contributed the most to radiation exposure from the air pathway. You can read about the potential health effects of iodine-131 in the Network's Health Bulletin. Another Network publication, Potential Health Problems from Exposure to Selected Radionuclides, addresses the possible health effects from five other radionuclides released to the air for which the Hanford Environmental Dose Reconstruction Project has estimated doses.

Hanford discharged three kinds of pollutants into the Columbia River: heat, chemicals and radioactive material. River water was used to cool the reactors. Before running the water through the reactors, Hanford added chemicals to keep pipes clean in the cooling system. As the cooling water was piped through the reactors, it picked up radiation as well as heat. All three types of pollution were discharged into the Columbia with the cooling water. Because the Network's Congressional mandate directs us to focus on radiation released from Hanford, this report will focus on the radioactive material.

Five radionuclides contributed the most to radiation dose from the Columbia River:

arsenic-76 neptunium-239 phosphorus-32 sodium-24 zinc-65

The Dose Reconstruc- tion Project estimated that these radionuclides accounted for more than 94 percent of the poten- tial radiation dose from the river pathway.

According to the Technical Steering Panel of the Hanford Environmental Dose Reconstruction Project, there were five radionuclides that contributed the most to radiation dose from the river pathway (dose is the amount of radiation absorbed by a person's body). The five radionuclides were phosphorus-32, zinc-65, arsenic-76, neptunium-239 and sodium-24. The Dose Reconstruction Project estimated that these radionuclides accounted for more than 94 percent of the potential radiation dose from the river pathway. There were many other radioactive materials released into the river as well, but they contributed much less to dose, according to the Technical Steering Panel.

This report examines the releases of these five radionuclides to the Columbia River and the potential health effects which might result from people being exposed to these materials.

The Columbia River and the Hanford Site (CLICK TO ENLARGE)

What are the possible health problems from exposure to radioactive forms of phosphorus, zinc, arsenic, neptunium and sodium? Most of the information on health effects from these materials has come from research on animals. None of these studies contains information that relates to the specific situation of people who lived or spent time downriver from Hanford. While comparisons of these studies to the Hanford situation are uncertain, this report discusses potential health problems which may have been caused or could be caused by exposure to these radionuclides.

Radiation health scientists assume that any dose of radiation, however small, carries with it an increased risk of some adverse health effect, such as cancer or other problems. This does not mean that everyone who receives an exposure will suffer an effect. It means the risk of a radiation-induced health problem is increased. Even if a particular person gets sick, it is not possible to determine, with current scientific methods, if the illness was caused by radiation exposure.

How Hanford Radiation Polluted the Columbia

Causes of Contamination

The primary cause of the radioactive pollution of the Columbia River was from the routine operation of the first eight plutonium production reactors. The first three were built during World War II and five more were added between 1949 and 1955. The first reactor began operating in September 1944 and the last one shut down in January 1971.

How radiation entered the Columbia River 1. River water was used to cool the reactors, then was returned to the river after a brief holding period. 2. Circulating through the reactors made some materials in the cooling water radioactive. 3. When the holding period was shortened, there was less time for radiation to decay before cooling water went back into the river. 4. When fuel coverings split, some radioactive fuel went into the cool- ing water and the river. 5. "Purges" that cleaned the cooling pipes sent additional radioactivity into the cooling water and the river.

The nuclear reactions inside these reactors created plutonium and great amounts of heat. The cooling system used water from the Columbia River, ran it through pipes in the core of the reactors, and then back into the Columbia. This process was called "once-through cooling."

There were various chemicals in the cooling water. Some of these occurred naturally in the river water. Others were added to treat the water before it entered the reactors and to keep the pipes of the cooling system clean. Some of these chemicals became radioactive when they were exposed to the intense radiation field in the reactor cores. Some of these chemicals contained phosphorus. Inside the reactor core, some of this phosphorus became radioactive phosphorus-32. As much as 25 to 40 percent of the phosphorus-32 released to the river came from the chemicals used for water treatment.³ The rest of the phosphorus that became radioactive was naturally occurring.

After leaving the cores, the discharged cooling water, or effluent, went into retention basins. The purpose of the basins was to allow time for some of the short-lived radiation to decay and the reactor-heated water to cool. The cooling water was near 200^o F when it left the reactors. It cooled somewhat while in the retention basins, but was still much hotter than the river temperature when it was discharged back to the river. The basins were designed to have a retention time that ranged from two to six hours. After flowing through the retention basins, the cooling water was discharged into the Columbia River.

In addition to adding five reactors, Hanford increased the power levels of all eight reactors to produce more plutonium for the country's nuclear arsenal. As a result, more radioactivity was discharged into the Columbia. The reactors needed more cooling water to operate at higher levels. The greater flow of cooling water reduced the retention time to as short as 20 minutes. This shorter retention time contributed to more radioactivity entering the river. The radioactive contamination levels in the Columbia River were highest from 1957 to 1964.

The ninth and last plutonium production reactor to be built at Hanford, the N reactor, had a different cooling system than Hanford's first eight reactors. Like commercial nuclear power reactors, the N reactor had two cooling systems. The two cooling systems are designed so that the cooling water that is exposed inside the reactor core is not released back into its source. The N reactor, therefore, did not significantly contribute to the pollution described in this report. The N reactor operated from 1963 to 1987.

In addition to the increased power levels and the resulting decreased retention time, there were two other causes of radioactive pollution entering the Columbia River from Hanford. These were fuel element failures and reactor purges.

The nuclear fuel consisted of fuel "elements" which were less than two feet long and encased in metal. There were thousands of fuel elements in each reactor. The increase in the reactor power levels put more stress on the fuel elements. Under this stress, the metal covering could split and allow small chunks of the radioactive fuel to be flushed into the river with the cooling water. The largest chunk weighed more than a pound. There were nearly 2,000 fuel element failures during the operation of the eight original plutonium production reactors.

Purging the reactor piping also contributed to the contamination of the river. Impurities in the cooling water entering the reactor caused a film to build up on the inside of the cooling pipes within the reactor. This film was radioactive. As it built up in the pipes, it increased the radiation exposure to workers in the reactor buildings. Periodically, the piping system was flushed with chemicals to strip off the film. These were called "reactor purges." When the accumulated film was purged, it went through the retention basins, then into the river and contributed to the contamination of the Columbia.

Factors Influencing Radiation Exposure

In addition to the causes of radioactive contamination discussed above, there were two factors which influenced the amount of radiation people were exposed to: seasonal changes in the Columbia and the addition of dams.

When seasons change, so does the Columbia. In the spring, the river is swollen with runoff from the melting snowpack. There is more water flowing and it is moving faster. This helped dilute the concentration of radioactive material in the river water. The temperature of the water is also affected: cooler in the large flows of winter and spring, warmer in smaller flows of summer and fall. The cooler water of winter and spring decreased the amount of radionuclides absorbed by fish because their metabolisms slowed and they ate less. Summer and fall brought smaller flows, warmer water and a resulting higher concentration of radioactivity. Summer and fall, then, were the times when exposures likely peaked in river areas near Hanford, especially during September, October and November.

Why the concentration of radioactive material in the Columbia River differed over time 1. Seasonal changes in the Columbia and new dams affected the amount of radiation to which people were exposed. 2. Lower flow in the Columbia River and higher temperatures in summer and fall led to higher concentration of radioactivity in those seasons. 3. September, October and November were likely the times of high- est exposure in the Columbia near Hanford.

Dams also affected the flow of the Columbia River. In 1944, Bonneville was the only dam downstream from Hanford. By 1971, there were four. (See map above.) The dams changed the way radioactive materials were carried and distributed down the river in two main ways. First, the dams slowed the flow of the river. This slower flow allowed more of the radioactive materials to decay before reaching people farther downstream from the Tri-Cities (Richland, Pasco and Kennewick). Second, the radioactive materials downstream were further decreased because some adhered to the sediment trapped behind the dams.⁴

In short, Hanford polluted the Columbia River by releasing radioactive materials from the plutonium production reactors. Next, this report will examine how people were exposed to Hanford's radiation from the Columbia River pathway.

How People Were Exposed to Radiation from Hanford

People were exposed to Hanford's radiation via the river pathway if they:

drank contaminated water;

ate contaminated food (fish, shellfish or waterfowl); or

• spent time along the shoreline of or swam in the contaminated stretches of the Columbia River.

Contaminated drinking water was the largest contributor to a typical person's dose from the river pathway. Eating contaminated foods was the next significant contributor to dose, followed by exposure while boating or swimming. The contribution from eating crops that had been irrigated by Columbia River water was estimated by the Dose Reconstruction Project to have been so small that it was not included in the dose estimates.

People who drank water from the Columbia River downstream of Hanford between 1944 and 1972 would have been exposed to radiation.⁵ Some communities drew drinking water from the Columbia. The water treatment system of Pasco had special filters that captured some of the radioactive materials. The city of Richland did not draw its water from the Columbia until October 1963. Prior to this, its water supply came from the Yakima River.⁶ Not all cities took drinking water from the Columbia. For example, Portland, Oregon got its drinking water from a reservoir near Mt. Hood.

People were exposed to radiation in the Columbia River by drinking contaminated water from the river; eating contaminated fish, shellfish or water- fowl; spending time along the shoreline of contami- nated stretches of the river; boating or swimming downstream from the Hanford reactors; and/or eating fresh produce irrigated with contami- nated water.

Other people drank untreated river water. One example is those who worked on barges transporting goods along the river. The common practice of the barge crews was to drop a bucket into the river to get their drinking water. In 1956, Hanford officials considered issuing restrictions on drinking untreated river water. They concluded that restrictions were "not essential." They also noted that "public relations might suffer from such restrictions." ⁷

The second source of exposure in the river pathway was from eating contaminated food: fish, shellfish and waterfowl.⁸ As is discussed later in the next section, Columbia River fish were contaminated.

The radiation in the Columbia also reached the Pacific Ocean, contaminating shellfish along the Washington and Oregon coasts. The levels of zinc-65 in the oysters of Willapa Bay on the Washington coast were monitored beginning in 1959. According to a 1959 Hanford document, the levels of zinc-65 in Pacific oysters were more than 300 times higher than in Japanese or Atlantic coast oysters.⁹

Ducks and geese that nested or fed along the Columbia became contaminated. Waterfowl also picked up radioactivity from waste ponds on the Hanford site. The contamination levels were higher in birds collected on the Hanford site than in those from the areas surrounding Hanford. In early 1970, several ducks collected from waste ponds near the reactors were found to be very contaminated. If someone had immediately eaten one-half pound of the most contaminated duck, the radiation dose to the bone would have been four times higher than the annual acceptable standard at the time.¹⁰

People with unique lifestyles may have eaten other kinds of contaminated food. For example, Native Americans ate shoreline roots and berries.

The third source of exposure was from spending time along the shore, swimming or boating downstream from the Hanford reactors. Most of this exposure was in the form of external, whole-body radiation. Some people have recalled that in the 1950s and 1960s, they preferred swimming near Hanford because the water felt warmer there than further downstream.

Hanford and Columbia River Fish

Hanford scientists began studies on Columbia River fish in 1945. They wanted to learn if the reactor effluent which was discharged to the river had any effect on fish. They constructed a laboratory at Hanford near the reactors. Young fish were exposed in tanks to various concentrations of effluent, usually at levels much higher than Hanford was releasing to the Columbia River.

There are two kinds of fish in the Columbia River: anadromous and resident.

Anadromous fish are those that hatch in fresh water and return there to spawn, but spend most of their lives in the ocean. Some examples of anadromous fish are salmon and steelhead trout. These two types of anadromous fish are the most valuable to the region's economy and to Native Americans.

The early Hanford studies were concerned primarily with young Chinook salmon and steelhead trout. Eggs and young fish were exposed to higher concentrations of effluent than were actually present in the river. Many died. However, Hanford scientists determined that the cause of death was not exposure to the radioactivity. The fish deaths were determined to be due mainly to the chemicals added to pretreat the cooling water and the increase in water temperature.¹¹ The studies did not examine the long-term effects of exposure in the fish.

When mature anadromous fish return from the ocean to fresh water, they do not feed. Since they are not exposed by eating contaminated smaller fish, they are not thought to accumulate much radioactive contamination. Due to significant public concern, the Dose Reconstruction Project is planning additional work on the radiation levels that were present in anadromous fish as they came up the Columbia to spawn.

Fish were exposed by:

eating smaller fish; eating algae, insects or other small aquatic creatures; and /or having water pass through their gills.

Waterfowl were exposed by:

nesting or feeding along the Columbia River; and /or nesting or feeding at waste ponds on the Hanford site.

Resident fish are those that live their entire lives in fresh water. Examples of resident fish are crappie, bass, river trout, whitefish and sturgeon. Due to spending more time in the contaminated portions of the Columbia River than anadromous fish, the resident fish collected higher concentrations of radioactivity. Most of the radiation in the fish came from eating smaller aquatic creatures such as algae and insects. The algae could concentrate the radiation up to 100,000 times the levels of contamination in the river water.

Resident fish in the Hanford area readily accumulated the radioactive phosphorus in their bodies because the levels of natural phosphate in the river were low.¹² The whitefish had the highest concentrations of phosphorus-32. Because of this, Hanford researchers selected whitefish as the focus of their fish monitoring efforts.

The Hanford Health Information Network has received several questions about the radioactivity levels in sturgeon. The concern is raised because sturgeon feed off the bottom of the river where radioactive sediments are found and because sturgeon can live more than 100 years. Based upon studies conducted by Hanford, scientists concluded that eating sturgeon would have given a lower dose than eating crappie, perch or bass. This lower exposure was due to lower concentrations of radioactivity in the sturgeon and people catching fewer sturgeon than other fish.¹³ However, a scenario of a person eating large quantities of sturgeon is entirely reasonable and this diet could have resulted in a higher exposure.

Official Concerns in the Past

Did Hanford pose a danger to the fish and to people who ate fish? The historical record is not consistent. Based on the laboratory studies and the monitoring of the river, Hanford scientists and government officials concluded that "the effluents were diluted to relatively safe levels" based on standards at the time. ¹⁴ However, some health officials in the past expressed serious concern about the contamination levels in the Columbia River.

Hanford exposure and fish

Fish living in the Columbia year-round ("resident fish"), such as crappie, bass, river trout, whitefish and sturgeon, had higher concentrations of radioactivity than fish that only hatched and spawned in the Columbia ("anadromous fish"). Resident fish near Hanford easily collected radioactive phosphorus in their bodies because the Columbia was low in natural phosphate. Whitefish had the highest concentrations of phosphorus-32. The Dose Reconstuction Project will look further at the radiation levels that were in anadromous fish as they came up the Columbia to spawn. Anadromous fish include salmon and steelhead trout.

During Hanford's early years, Herbert M. Parker was in charge of the health and safety programs.¹⁵ In 1954, as he considered the projected increases in radiation being released into the Columbia from the reactors, Parker suggested that it might be necessary to impose a public fishing ban from just above Hanford (Priest Rapids) downriver to McNary Dam.¹⁶ Parker noted that the "public relations impact would be severe." According to a report by the Hanford Education Action League, a nonprofit organization based in Spokane, Wash., "Although no fishing ban was ever imposed, the radiation levels in Columbia River fish surpassed the point at which Parker had considered a fishing ban during the years 1957, 1958, 1960, 1961, 1963 and 1964." ¹⁷  

 

Nor was concern focused only on the section of the Columbia nearest to Hanford. In 1964, the U.S. Public Health Service recommended that immediate action be taken to cut in half the radioactivity levels in "the Lower Columbia River."¹⁸ Although not specified in this report, the Lower Columbia was usually referred to as downriver from McNary Dam to below Portland. (See map above.)

Current Concerns

Many people have expressed concerns about the radioactive materials from past releases that are trapped behind Columbia River dams, especially McNary. However, a Washington Department of Health report has concluded that the risk for adverse health effects is less than that associated with federal and state drinking water standards.¹⁹ This could change if the sediments were dredged (although this is unlikely).

downwinder perspective

Many callers to the Hanford Health Information Lines have questions and concerns about the release of radioactive materials to the Columbia River and possible effects on humans and on fish. Some downwinders have health problems that they believe are, or might be, related to Hanford. The following personal perspective is offered to help readers understand these experiences and concerns.

"I'm a member of the Confederated Tribes of the Umatilla Indian Reservation, located some 60 air miles southeast of the Hanford Nuclear Reservation.

"My mother was born at Plymouth, Wash., across the Columbia River from Umatilla in Eastern Oregon, just downstream from where McNary Dam is now. My mother's immediate and extended family practiced extensive use of the river and its inhabitants. This background is what interested my ensuing relationship with the Columbia River.

"I first went to Celilo Falls at age 11 in the early 1940s. Here I caught and handled a lot of salmon during the span of three fall fisheries.

"First, I was a fish buyer for my uncle and secondly, an enterprising fisherman. Since I had no scaffold of my own to fish, I moved around to available places and had a lot of fun. My family wasn't dependent upon the fisheries, but we consumed a lot of salmon.

"To the best of my knowledge, there have been little ill effects to myself or my immediate family from Hanford's radioactive releases into the Columbia River. However, the river is very sick.

"There are many questions from Tribal members who have spent more of their time around the river, about the deaths of their relatives. They have many unanswered questions about what happened at Hanford and how it could affect us.

"At this point we don't have any definite answers that say this was a result of something that was released to the water or air from Hanford. All we know about radionuclides is, you can't see them, hear them, smell them or taste them - but they can affect you."

- Name withheld by request

Hanford Dose Estimates

The Dose Reconstruction Project has calculated "representative dose estimates." For the river pathway, these are estimates of dose for three typical lifestyles with variations in food and water consumption and place of residence.

The lifestyles of actual individuals, such as those who subsisted on fish, might be different than the "representative" categories. Many Native Americans rely heavily on fish, especially salmon, for food. The Columbia River Inter-Tribal Fish Commission (CRITFC) recently surveyed the fish consumption of Native Americans in the Columbia River Basin. The results show that the average fish consumption rate for Native Americans using the Columbia River is "approximately nine times greater" than for the general U.S. population.²⁰

COLUMBIA RIVER FISH CONSUMPTION (pounds per year)
Native American Survey (CRITFC)	Average 47	Highest greater than 137
Hanford Dose Reconstruction Project	"Typical Individual" 4-5	"Maximum Individual" 93

Although the Network's previous report on the radionuclides released to the air contained the range of representative dose estimates for each radionuclide, the same level of information for radionuclides released to the river is not available. The Dose Reconstruction Project's estimates of exposures from the river pathway are generally much lower than those from the air pathway. Because of this, the Dose Reconstruction Project did not go into as much detail for the dose estimates via the river pathway.

The cumulative (1944-1971) representative dose estimates for adults from the five radionuclides released to the river range from near zero to about 1.5 rem EDE (Effective Dose Equivalent-whole-body dose). The dose estimates to specific organs (red bone marrow and lower large intestine) are higher. These estimates are in Dose Reconstruction Project reports but only for the period 1950 through 1971. In most cases, the farther downstream from Hanford, the lower the exposure.

In order to give a sense of how large a dose 1.5 rem EDE is, a comparison with background radiation is sometimes made. During the same period (1944-1971), an average adult would have received a dose of about 9 rem EDE (whole body) from background radiation. The sources of background radiation include radon, medical procedures and cosmic rays. Please note that exposure to background radiation may cause adverse health effects.

Representative dose estimates for the river pathway were not calculated for infants and children.²¹ For the air pathway, the highest representative dose estimates were for infants and children. Also, dose estimates for the air pathway were reported in a range that was descriptive of the uncertainty in the estimates. The uncertainty range was not reported for the river pathway.

Possible Health Problems

Please keep the following points in mind when reading the sections on the possible health problems connected with the following five radionuclides: Most of the research associated with these radionuclides has been done on animals. Comparing the health effects on animals and on people exposed to radiation from Hanford is difficult for three main reasons: The life span of human beings is much longer than that of the animals used in studies. Some diseases, such as cancer, may not be detected for several decades. It is uncertain if humans are affected in the same way as animals. Most of the animal studies involved exposure to very high levels of radiation over a short time (equivalent to a human exposure of thousands of rem). Hanford exposed people to lower levels of radiation but over a long time. Due to the very small amount of information available on the health effects specific to these five radionuclides, people are advised against making direct comparisons to people exposed to radioactive releases from Hanford.

Since the release of the first 19,000 pages of Hanford historical documents in 1986, much has been learned. However, the information available is not enough to form a complete assessment of the impact of Hanford's releases. This section provides information about each of five radionuclides. The same categories of information are presented for each:

1. a general description of the radionuclide;
2. the estimated amount released from Hanford from 1944 to 1971;
3. the possible health effects;
4. the organs estimated to have received the main dose from the Hanford exposures; and
5. a summary of health studies.

The amounts released, calculated doses and organs receiving the main dose are estimates of the Hanford Environmental Dose Reconstruction Project. The five river pathway radionuclides are presented in alphabetical order.

Arsenic-76

Description: The half-life of the radionuclide arsenic-76 is 26.3 hours. It emits beta and gamma radiation.

Estimated Amount Released: 2,500,000 curies

Possible Health Effects: No studies were found specific to arsenic-76.

Organs Receiving Main Dose: Gastrointestinal tract, stomach for infants

Summary of Health Studies The Network's research has been unable to find any studies on the effects of exposure specific to arsenic-76. Chemically, arsenic, in sufficient concentrations, is a poison and can cause cancer. Chronic exposure to arsenic can cause the following cancers: lung, skin and stomach (from the chemical toxicity).

Neptunium-239

Description: Neptunium-239 has a half-life of 2.4 days. It emits beta and gamma radiation. Neptunium-239 decays into plutonium-239 which has a half-life of 24,000 years and emits alpha radiation. The amount of neptunium-239 released to the Columbia River decayed to about 1.7 curies of plutonium-239.

Estimated Amount Released: 6,300,000 curies

Possible Health Effects: Bone cancer

Organ Receiving Main Dose: Gastrointestinal tract

Summary of Health Studies

Most of the neptunium that is retained in the body deposits in the bones. Some is also retained in the liver. Several studies report "relatively high concentrations" of neptunium in adrenal glands of laboratory animals.²²

No health effects specific to exposure from neptunium "have been observed" in human beings.²³ Roy C. Thompson, Biology Department of Battelle Pacific Northwest Laboratory in Richland, conducted an extensive review of studies involving neptunium.

This review included Russian studies that found an increase in the number of bone tumors in animals receiving bone doses as low as a few rad. Thompson concluded that "there can be little doubt" that neptunium can cause cancer in bone.²⁴

In 1984, a team of German scientists reported preliminary results of an experiment with mice designed to measure the combined effect of having neptunium-239 deposit in bone and decay into plutonium-239. These initial results found evidence that the buildup of plutonium-239 (as the neptunium decayed) increased the number of bone tumors compared to those expected from exposure to neptunium alone.²⁵

Phosphorus-32

Description: Phosphorus-32 has a half-life of 14.3 days. It emits beta radiation. Biologically, nonradioactive phosphorus is vital to living things because it enables the transfer of energy in metabolism. It is also an important ingredient in bones.

Estimated Amount Released: 230,000 curies

Possible Health Effects: Bone cancer, leukemia

Organ Receiving Main Dose: Red bone marrow

Summary of Health Studies

Once inside the body, phosphorus concentrates in the bone. In experiments on rats, phosphorus-32 was found to be "potent" in causing bone cancer.²⁶

Based on studies of human patients with a blood disease treated with phosphorus-32, there may be an "increased incidence of leukemia."²⁷ A review article of several studies of people with the same blood disease who were followed until death reported that of those treated with phosphorus-32, 16 percent had developed acute leukemia compared with only 1.6 percent of those not treated.²⁸

Sodium-24

Description: Sodium-24 has a half-life of 15 hours, the shortest half-life of the five radionuclides. It emitsbeta and gamma radiation.

Estimated Amount Released: 12,000,000 curies

Possible Health Effects: No studies were found specific to sodium-24.

Organ Receiving Main Dose: Stomach

Summary of Health Studies

The Network's research has been unable to find any studies on the effects of exposure specific to sodium-24.

Zinc-65

Description: Zinc-65 has a half-life of 245 days, the longest half-life of the five radionuclides. It emits beta and gamma radiation. Biologically, nonradioactive zinc is needed. "Too little zinc in the diet can lead to poor health, reproductive problems and lowered ability to resist disease."²⁹

Estimated Amount Released: 490,000 curies

Possible Health Effects: Damage to enzymes and hormones

Organ Receiving Main Dose: Whole body

Summary of Health Studies

The principal health effect of zinc-65 is from the radiation exposure. If zinc-65 decays into copper while it is in an enzyme in the body, it can possibly have "drastic consequences."³⁰ One consequence is that exposure to zinc-65 might lead to the formation of autoantibodies (proteins that act against the protection mechanisms within one's own body). Evidence for this comes from a study on rabbits.^{31, 32}

Zinc also readily concentrates in the prostate when administered intravenously.³³ Because of this, radioactive zinc may be a factor in prostate cancer.³⁴

Summary

To conclude, we know that Hanford's plutonium production did cause extensive contamination of the Columbia River and parts of the Pacific Ocean along the coasts of Washington and Oregon. Fish and other wildlife using these waters were exposed to radioactive materials and other kinds of pollution. People using the waters and the aquatic resources were also exposed to measurable levels of radiation.

What remains uncertain is if and how the radiation released into the Columbia River affected human health. Many people have asked the Network questions about whether their exposure to the radioactive contamination in the Columbia River harmed their health. Unfortunately, there is not enough information to answer their questions.

Unresolved Issues

During the preparation of this report, the technical reviewers raised several points that could not be resolved.

David C. Kocher, Ph.D., was concerned that the presentation of the risk of possible health effects of the five radionuclides was incomplete. Readers should understand that, given the low dose estimates of the Dose Reconstruction Project, "there is no reason to believe that there was an observable increase in health effects in nearby residents due to releases to the river." Scientists are not now able to observe (or measure) health effects due to exposure to background radiation. Since the dose estimates for the river pathway are lower than background, scientists could not measure "health effects even if they existed, because the effects would be substantially less than those caused by natural background." Kocher is with the Health Sciences Research Division of Oak Ridge National Laboratory in Tennessee.

Norm Buske, M.S., was mainly concerned that possible health effects could not be "reliably appraised until Hanford's major releases have been identified." His assessment is that Hanford's dose reconstruction work has probably overlooked important radiological releases to the Columbia River. Buske suggested that the significance of these releases was "probably greater than anything yet reported" by the Dose Reconstruction Project. He asserted that the Dose Reconstruction Project should have included other radionuclides, such as chromium-51 and iron-59, in the dose calculations. Buske has presented his concerns to Hanford officials and is awaiting a response. He has a degree in oceanography and has done research on Hanford radioactive releases and the Columbia River over the last 10 years.

Greg deBruler served as the public representative on this report's Technical Review Panel. One of his major concerns is the dose estimates used in this report. "There is enough scientific uncertainty with the Dose Reconstruction Project that the representative dose estimates should not be treated as if they were scientifically proven facts. The HEDR dose estimates could be off by orders of magnitude of 10 or more." DeBruler reminds us of the statement in an HHIN document: "The basic assumption of radiation protection standards is that any exposure to radiation poses a health risk." The review of this document does not reflect all of the comments or concerns he submitted. DeBruler is a technical consultant to Columbia River United, a nonprofit organization based in Hood River, Oregon.

Notes

1 Oregon Health Division, Radiation Protection Services. "Environmental Radiological Surveillance Report on Oregon Surface Waters, 1961-1993." Dec. 1994, p. 1.

2 The Hanford Environmental Dose Reconstruction Project is the only study estimating the doses from radiation received by people exposed to Hanford's releases of radioactive materials. The public has access to the work of the Dose Reconstruction Project and is invited to attend the meetings of the Technical Steering Panel, which directs the study. When using information from the Dose Reconstruction Project and other studies, readers should keep in mind that research results depend on a number of factors, such as the information available, and the methods and type of analysis used.

3 WH Walters, et al. "Literature and Data Review for the Surface-Water Pathway: Columbia River and Adjacent Coastal Areas." PNL-8083, Battelle: April 1992, p. 5.5.

4 For further reading on radiation trapped in sediments, see D Wells, "Special Report: Radioactivity in Columbia River Sediments and Their Health Effects." Washington Department of Health, Division of Radiation Protection; Mar. 1994.

5 Although the amounts are much smaller, radioactive material continues to enter the Columbia River from Hanford's contaminated groundwater. This publication covers only the years 1944-1972, as directed by the Network's mandate.

6 WT Farris et al. "Columbia River Pathway Dosimetry Report, 1944-1992." PNWD-2227; July 1994, p. 4.4.

7 "Radiation Aspects for River Navigation Through Hanford Project." HW-47152; Dec. 7, 1956, p. 2.

8 For additional information, see RW Hanf et al. "Radioactive Contamination of Fish, Shellfish, and Waterfowl Exposed to Hanford Effluents: Annual Summaries, 1945-1972." PNWD-1986; July 1992.

9 RL Junkins, et al. "Evaluation of Radiological Conditions in the Vicinity of Hanford for 1959." HW-64371. Also "Quarterly Progress Report: October-December 1959." HW-63643; pp. 19-20.

10 JP Corley. "Environmental Surveillance at Hanford for CY-1970." BNWL-1669; Sept. 1973, pp. 3, 35. Due to changes in how doses are calculated, it was not possible to make a comparison with current standards.

11 CD Becker. Aquatic Bioenvironmental Studies: The Hanford Experience, 1944-1984. Studies in Environmental Science, Volume 39. Amsterdam: Elsevier, 1990, pp. 96-97, 100, 110. Becker was in the Geosciences Department of the Pacific Northwest Laboratory at Hanford which is operated by Battelle.

12 CD Becker, p. 175.

13 DD Dauble et al. "Radionuclide Concentrations in White Sturgeon from the Columbia River." PNL-8221, Rev. 1; November 1993, p. 18.

14 CD Becker, p. 110.

15 Parker earned a Masters of Science in physics from the University of Manchester in England (1931). He then worked on using radiation to treat cancer in both England and the United States. For the four years immediately prior to World War II, Parker worked under Simeon Cantril at the Swedish Hospital Tumor Institute in Seattle. During the Manhattan Project, Parker worked to develop radiation protection procedures at Chicago, Oak Ridge and Hanford.

16 HM Parker. "Columbia River Situation-A Semi-Technical Review." HW-32809; August 19, 1954.

17 J Thomas. "Atomic Deception: Oh, What a Tangled Web!" HEAL Perspective. Summer/Fall 1992; (10-11): p. 7.

18 US Public Health Service. "Evaluation of Pollutional Effects of Effluents from Hanford Works." May 13, 1964.

19 D Wells. "Special Report: Radioactivity in Columbia River Sediments and Their Health Effects." Washington Department of Health, Division of Radiation Protection. Mar. 1994; p. 41.

20 CRITFC (Columbia River Inter-Tribal Fish Commission). "A Fish Consumption Survey of the Umatilla, Nez Perce, Yakama, and Warm Springs Tribes of the Columbia River Basin." CRITFC Technical Report No. 94-3, October 1994; p. 59.

21 WT Farris et al. "Columbia River Pathway Dosimetry Report, 1944-1992." PNWD-2227; July 1994, p. 4.8.

22 Roy C Thompson. "Neptunium-The Neglected Actinide: A Review of the Biological and Environmental Literature." Radiation Research. April 1982; 90: p. 18.

23 Thompson, p. 21.

24 Thompson, p. 24.

25 WA Müller, EH Schäffer, U Linzner, and A Luz. "Incorporation Experiments with Combined Application of Different Bone Seekers." Radiation Environment Biophysics. 1984; 23 (2): p. 115. The scientists were from Abteilung fÅr Pathologie, Gesellschaft fÅr Strahlen- und Umweltforschung, Neuherberg, Germany (in association with EURATOM).

26 Marvin Goldman, Ph.D., Laboratory for Energy-Related Health Research, University of California-Davis. "Experimental Carcinogenesis in the Skeleton." In Radiation Carcinogenesis, AC Upton, RE Albert, FJ Burns and RE Shore, eds. 1986; p. 220.

27 J Visfeldt, G Jensen and E Hippe. "On Thorotrast Leucaemia: Evolution of Clone of Bone Marrow Cells with Radiation-Induced Chromosome Aberrations." ACTA Pathologica et Microbiologica Scandinavica. July 1975; 83 (4): p. 377. Visfeldt is with the University Institute of Pathological Anatomy in Copenhagen, Denmark. Jensen is with the Institute of Pathology, Frederiksberg Hospital in Copenhagen. Hippe is with the Medical Department C at the Bispebjerg Hospital, also in Copenhagen.

28 G Rothstein and MM Wintrobe. "Preleukemia." Advances in Internal Medicine. 1975; 20: p. 367. Both authors were with the Department of Internal Medicine at the University of Utah College of Medicine in Salt Lake City.

29 Agency for Toxic Substances and Disease Registry (ATSDR). "Toxicological Profile for Zinc." Feb. 19, 1993; p. 2.

30 HF Schulte, Los Alamos Scientific Laboratory. Book review of The Toxicology of Radioactive Substances, Volume 5: Zinc-65. Health Physics. September 1971; 21 (3): p. 481.

31 PP Filatov. "The Effect of Chronic Exposure to Radioactive Zinc on Antibody Formation." The Toxicology of Radioactive Substances, Volume 5: Zinc-65. AA Letavet and EB Kurlyandskaya, eds. Oxford: Pergamon, 1970, pp. 138ff.

32 MF Cottrall. "Medical Research and Auger Cascades"(letter). The Lancet. Oct. 26, 1985; 2 (8461), pp. 942-943. Cottrall was with the Academic Department of Medical Physics at the Royal Free Hospital School of Medicine in London.

33 GR Prout et al. "Radioactive Zinc in the Prostate: Some Factors Influencing Concentrations in Dogs and Men." JAMA. April 11, 1959; 169 (15): pp. 1703-1710. Prout was with the Urologic Service of the Sloan-Kettering Institute.

34 A Hilson. "Prostatic Cancer and Radionuclides: Evidence Implicates Zinc-65" (letter). BMJ. January 22, 1994; 308: p. 268. Hilson is in the Department of Nuclear Medicine at London's Royal Free Hospital. Related Reading Available from HHIN HHIN, Potential Health Problems from Exposure to Selected Radionuclides (Released to the Air) HHIN, Radioactivity in the Body

Related Reading Available from HHIN

HHIN, Potential Health Problems from Exposure to Selected Radionuclides (Released to the Air)

HHIN, Radioactivity in the Body

A PUBLICATION OF THE Hanford Health Information Network

The Nervous System and Radiation

HERE YOU'LL FIND...

The Nervous System Health Effects of Radiation Hanford's Releases and the Nervous System What Information Is Needed? Notes Further Reading

Some people believe there is a higher-than-usual rate of nervous system disorders among individuals exposed to Hanford's releases of radioactive materials. To summarize what is known and provide discussion on this issue, the Hanford Health Information Network (HHIN) prepared this report about disorders of the nervous system and Hanford's radioactive releases.

Readers of this report will learn:

1. How the nervous system works.

2. The types of diseases that can afflict the nervous system.

3. The health effects to the nervous system connected with high-dose and low-dose radiation exposure.

4. Several viewpoints on information needed to determine whether there is a relationship between Hanford's radiation releases and health effects of the nervous system.

The Nervous System

The nervous system coordinates and regulates the body's activities. This includes automatic actions, such as breathing and heart pumping, and voluntary actions, such as eating, running and reading.

The nervous system consists of the brain, the spinal cord and the peripheral nerves which extend from the spinal cord. The nervous system is like an electronic communication network. The spinal cord is the main cable through which messages enter and leave the brain. The nerves are the wires that run from the spinal cord to all parts of the body and carry messages to and from the brain. Messages travel along the nerves as electrical impulses.

Brain

The brain organizes the various activities of the body into one unit. The brain controls the body's automatic functions and muscles, and is the center for learning, thinking, reasoning, memory and emotions. It also interprets sensations including sight, smell, hearing, taste, touch, hunger and thirst.

Spinal Cord

The spinal cord is housed within the bones of the spinal column formed by the vertebrae. The spinal cord is made of hundreds of nerve fibers. It carries messages to and from the brain. It is also the center for certain reflexes such as deep tendon reflexes. An example of a deep tendon reflex is a knee jerk when the knee is tapped.

Peripheral Nerves

The peripheral nerves carry messages from the brain and spinal cord to other parts of the body.

NERVOUS SYSTEM DISEASES

Examples of diseases of the nervous system include multiple sclerosis, myasthenia gravis, Parkinson's disease, amyotrophic lateral sclerosis (ALS – also known as Lou Gehrig's disease), Alzheimer's disease and brain tumors. Birth defects of the nervous system include neural tube defects, mental retardation and small brain size.

Some diseases cause symptoms in many parts of the body, including the nervous system. Chronic fatigue syndrome is a disease for which there is no identified cause, but there are nervous system symptoms.

Many of these diseases and problems affecting the nervous system have no known cause. The nervous system can be affected by infection, trauma, toxins, and metabolic, nutritional and genetic factors. It is not known to what degree radiation exposure may be a contributing factor to some of these diseases.

Health Effects of Radiation

Researchers know more about how high-dose radiation affects the nervous system than about how low-dose radiation affects it. Researchers also know more about exposures from external sources than from radioactive substances acting within the body (internal exposure). Hanford's releases, however, resulted in low whole-body doses from mainly internal exposure, according to estimates of the Hanford Environmental Dose Reconstruction Project.¹ Nonetheless, to understand the range of potential health effects, it is useful to look at what is known about the health effects of high-dose radiation from external exposures.

HEALTH EFFECTS OF HIGH-DOSE RADIATION

High doses of radiation can be defined as greater than 50 rem to the whole body. High-dose radiation is used to treat cancer. In the past it was used to treat benign conditions such as ringworm of the scalp and enlargement of the thymus gland in the neck. Some Japanese atomic bomb survivors, nuclear industry workers and survivors of nuclear accidents also received high doses of radiation. Health effects in people exposed to high radiation doses include effects on the brain, spinal cord and peripheral nerves.

Effects on the Brain

People treated with radiation for brain tumors often receive doses of a few thousand rad to the head, usually over a period of days or weeks. Health effects that can occur within days or weeks of treatment include swelling of the brain, seizures, paralysis and confusion. Long-term effects that may occur include the destruction of brain cells, changes in the blood vessels of the brain, seizures and confusion.²

Elaine Ron, Ph.D., and others conducted a study of Israeli children treated with radiation for ringworm of the scalp. The researchers estimated the dose to the brain for this group as between 100 and 200 rad. This group had a higher rate of cancerous and benign brain tumors than unexposed groups.³

Other studies have also linked radiation exposure to the development of brain tumors.⁴ These were studies of people treated with radiation for conditions of the head and neck, arthritis of the spine and acute lymphocytic leukemia.

However, studies of Japanese atomic bomb survivors have not reported a link between high-dose radiation exposure and brain tumors.⁵ While these studies found no evidence of a radiation effect for brain tumors, there is evidence of an increased risk for other nervous system tumors in people exposed to the atomic bomb explosions before they were 20 years old.⁶ These atomic bomb studies have, however, found measurable nervous system effects on some children born to Japanese women who were pregnant during the bombings of Hiroshima and Nagasaki. The women received whole-body radiation doses ranging from 50 to 100 rad between eight and 25 weeks after conception. The children had an increased risk for small brain size and mental retardation, lower intelligence test scores and decreased school achievement.⁷

Effects on the Spinal Cord

The spinal cord is generally more sensitive to the acute (short-term) effects of radiation than is the brain. It also takes less time for radiation-induced damage to the spinal cord to show up than similar injury to the brain.

Myelitis, or inflammation of the spinal cord, can occur within two to four months after a patient being treated with radiation is exposed to thousands of rad. Myelitis may have symptoms of tingling, prickling and shock-like sensations.

Myelitis is sometimes delayed, not occurring until four months to three years after radiation exposure. This delayed effect is due to scarring of the spinal cord and is not a direct effect on spinal cord nerve cells. When delayed, a person may experience more severe problems such as paralysis and lack of bladder control.⁸ Another delayed effect of high-dose radiation exposure to the spine is the development of spinal cord tumors years after the radiation exposure.⁹

Health effects in people exposed to high radiation doses include effects on the brain, spinal cord and peripheral nerves.

Effects on the Peripheral Nerves

Peripheral nerves (which connect the brain and spinal cord to other parts of the body) are among the parts of the body most resistant to radiation.¹⁰ Nonetheless, the Israeli children discussed above in the study by Ron and her colleagues had a higher rate of cancerous and benign tumors of peripheral nerves than people not exposed to radiation.¹¹

Localized treatment with high doses of radiation has also been reported to injure a group of nerves that extends from the lower neck to the underarm area. This group of nerves is called the brachial plexus.

HEALTH EFFECTS OF LOW-DOSE RADIATION

Birth Defects of the Nervous System in Children of Hanford Workers

Lowell Sever and others conducted a case-control study of children born in the Hanford area.¹² The researchers investigated if there was a link between a parent's work exposure to low-level external radiation and birth defects in that worker's children. The study investigated births between 1957 and 1980 since only a few hospital records were available for earlier years.

The researchers found that the higher the radiation dose received by parents before their children were born, the more likely the children were to be born with neural tube defects. Defects of the neural tube, which develops into the spinal cord and brain, occur when the tube fails to close completely during the early stages of pregnancy.

Researchers also reported a link between parental employment at Hanford and two non-neurologic birth defects: congenital dislocation of the hip and tracheoesophageal fistula, an abnormal connection between the trachea (the windpipe) and the esophagus (the part of the digestive tract that connects the mouth to the stomach). However, these two birth defects were not linked with parental exposure to radiation as not all Hanford workers were exposed to radiation at work. Many worked in offices and did not receive any occupational radiation exposure. This study did not include parents' exposure to radioactive materials outside of work, including environmental releases from Hanford, medical procedures or background radiation.

Birth Defects of the Nervous System in Communities near Hanford

Sever and others also conducted a study of the rate of birth defects in communities near the Hanford Site.¹³ The researchers investigated whether rates of birth defects among infants in the Hanford area were higher than expected potentially because of exposure to radioactivity from Hanford operations.

The researchers determined the rates of certain birth defects for Benton and Franklin counties in Washington state between 1968 and 1980. The Hanford Site covers part of both Benton and Franklin counties. These rates were compared to rates from the Centers for Disease Control's Birth Defects Monitoring Program for Washington, Oregon and Idaho. While the overall rate of birth defects in Benton and Franklin counties was not greater than expected, the rate of certain neural tube defects was increased.

The researchers compared the study group to other radiation exposed groups. They considered the Hanford doses too low to account for the elevated rates of neural tube defects as being caused by radiation exposure. The researchers did not have an explanation for the elevated rates but proposed that exposure to agricultural chemicals be considered.

The study was conducted before any dose estimates were available from the Hanford Environmental Dose Reconstruction Project. Also, the study's dose estimate for the public includes only the years 1974 through 1980, during which there were limited Hanford operations and emissions.

Brain Tumors Among U.S. Nuclear Workers

Deaths from brain tumors are unusual in the general population (4.1 deaths per 100,000 people). In a work force of several thousand, even a small number of cases (two to five) points to a higher number of such deaths than would ordinarily be expected.

Victor Alexander reviewed studies of workers at 10 nuclear facilities.¹⁴ Radiation doses were available for workers at eight of the facilities. For three of the groups, doses

Determining the occurence of nervous system diseases can be difficult.

included both external and internal exposure. Cumulative average whole-body doses ranged from 0.67 rem to 4.75 rem. There is a small group of workers who had higher doses, perhaps as high as 100 rem. However, individual doses for the workers who developed brain cancer were not provided.

The researcher concluded that there was a higher than expected number of deaths from brain cancer among the nuclear industry workers studied. While chemical exposure may contribute to the risk of cancer, the only common factor among the workers was exposure to radiation.

In summary, some researchers have linked certain nervous system health effects to radiation exposure. Health effects linked to high-dose exposure include cancerous and benign brain tumors in people exposed, and small brain size and mental retardation in children of women who were exposed during pregnancy. Health effects linked to low-dose exposure include brain cancer among nuclear industry workers.

Hanford's Releases and the Nervous System

Unfortunately, most of what is known about radiation's effects on the nervous system cannot be directly compared with the Hanford situation. Current knowledge comes from studies of people exposed to high organ doses or high whole-body doses of radiation received over minutes, hours or days. In contrast, Hanford's releases resulted in some high radiation doses to the thyroid, some low doses to other organs, and low whole-body doses. These doses occurred over weeks, months or years.

While most studies of radiation's effect on the nervous system involve external exposure, most of the dose from Hanford's releases came from internal radiation exposure. People were internally exposed when they drank contaminated milk or water, or ate contaminated foods. Because the circumstances of the studies discussed above differ from the Hanford situation, the conclusions of those studies do not necessarily apply to Hanford-exposed people.

Occurrence of Nervous System Diseases

Some people believe there is a higher than usual occurrence of nervous system diseases among people exposed to Hanford's releases of radioactive materials. Determining the occurrence of nervous system diseases can be difficult. For most of these diseases, only estimates are available of the number of cases in the United States, since there are no requirements to report nervous system diseases to health officials. Little or no information has been collected about the number of cases of many of these diseases among people exposed to Hanford's releases of radioactive materials. As a result, it is not possible, with the information currently available, to determine if the occurrence of nervous system diseases among Hanford downwinders is higher than usual.

What Information Is Needed? Since there have been no studies of people exposed to Hanford's off-site radioactive releases and nervous system effects, HHIN asked several individuals and organizations to respond to this question: What types of information would be needed to determine whether or not a relationship exists between health effects of the nervous system and exposure to radioactive materials released by Hanford from 1944 to 1972?

The people we invited to respond were selected to represent a broad range of perspectives, ranging from scientific experts to public interest organizations to individual citizens. Following are the responses HHIN received (listed in alphabetical order).

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Toomas Eisler, M.D.,Consultant in Neurology, Walla Walla, Washington

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It seems to me that I would need three pieces of information to determine the answer to this question. First, it is essential to identify the specific types of radioactive materials released from Hanford from 1944 through 1972 and their known environmental cycles. Secondly, I would need to know the nervous system response to these identified radioactive materials and the various levels of exposure to the whole body and to the specific sites in the body to which these radioactive materials may migrate. Thirdly, I would need actual epidemiologic data for the neurological diseases, disorders and dysfunctions in the Hanford area and also for a similar area that was not affected by radioactive materials of the same type.

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Warren M. Howe, Ph.D., Member of the Public, Pendleton, Oregon

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This report, while including valuable and important information, is not a carefully balanced one. It leads readers to the view that it is highly unlikely that we can determine that Hanford radiation releases were damaging to human health.

On the contrary, some respected researchers and low-level radiation experts (Drs. Ernest Sternglass and Alice Stewart) have concluded that low-level radiation exposure is extremely dangerous, much more so than some high-level radiation exposure. These views seem to run counter to conclusions made by the Sever study, cited in this report, that Hanford doses were "too low to account for the elevated rates of neural tube defects as being caused by radiation exposure."

Studies on relationships between health effects of the central nervous system and exposure to radioactive materials from sites other than Hanford could be done and could help establish such relationships in general. Also, as both Dr. Sternglass and Dr. Stewart have recommended, studies should be made comparing health risks for downwinders and for upwinders at Hanford, specifically for death rates from thyroid cancer.

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Jan Karon, Member of the Public, Pendleton, Oregon

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1. We need information about "low-dose" radiation: (a) What is the state of the controversy within the scientific community about whether or not ANY dose of radiation is "too low to account for" some health effects? (b) Might there be a relationship between the elevated rate of neural tube defects and low-dose radiation? (c) What are the results of animal studies of internal low-dose radiation exposure?

2. We need information about Hanford radiation releases: (a) What was released, how much of it, and over what period of time? (b) I recall that in the 1970s, game bird hunting was restricted around Vale, Oregon, allegedly because of Hanford releases. What were wind/weather conditions during that time?

3. We need demographic information on the exposed population, the state of health of the nervous system of those people and a comparative study of an unexposed population.

4. We need information that is credible to those who "believe there is a higher than usual occurrence of nervous system diseases among people exposed to Hanford's radioactive releases" and that information needs to be perceived as not being biased by the Department of Energy or any agency.

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Cheryl A. Kitt, Ph.D., Division of Demyelinating, Atrophic and Dementing Disorders, National Institute of Neurological Disorders and Stroke, National Institutes of Health

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This is a particularly difficult question to address, since the available information on the health effects on the central nervous system from radiation released by the Hanford facility, or any other nuclear facility, appears to be quite limited. One would need information regarding the radioactive source, such as what it was, how much was released, for how long, etc.

The report indicated that internal radiation is a major source of Hanford's exposure, but it is not clear how this was determined. It is absolutely critical to determine what the nature and extent of radiation exposure associated with Hanford was and to compare this with other similar situations. Control conditions must be carefully considered as well. For example, were individuals who were exposed to Hanford's releases also exposed to toxic chemicals? What were their prior radiation exposures, including those from medical procedures? In sum, carefully controlled epidemiological studies on the effects of high-dose and low-dose radiation are needed, in order to more fully understand whether the Hanford releases had harmful effects on the nervous system.

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Charles E. Land, Ph.D., Health Statistician, Radiation Epidemiology Branch, National Institutes of Health

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Given the probable radiation doses from radioactive materials released by Hanford and what is documented from populations exposed to much higher doses, I would not expect to find evidence of any radiation-related effects of the nervous system in the surrounding population.

It is extremely difficult to establish the existence of low-dose health effects based solely on low-dose data. This is because any excess health risks from low-dose exposures tend to be very small relative to background levels of the disease in question; that is, the "signal-to-noise" ratio of the data tends to be very low. One consequence of this is low statistical power, which essentially means that estimates of excess risk are influenced more by random and other uncontrolled variation than by the exposure under investigation.

I would, however, seriously consider the findings of any carefully controlled study of an exposed population with a reliable determination of radiation dose, and that found a clear relationship between dose and a health effect. Also, I would consider any independent evidence, not based on the disease under investigation, that radiation doses to neural tissue were on the order of tens of rad or more.

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Terry McCoy, Member of the Public, Waitsburg, Washington

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We need to know – perhaps by a random sampling/survey – the health status of the multitudes that lived in the affected area during the 1944-1972 period. For those who've died, what caused their death? What is the health condition of those still living?

HHIN asked several individuals and organizations to respond to this question: What types of information would be needed to determine whether or not a relationship exists between health effects of the nervous system and exposure to radioactive materials released by Hanford from 1944 to 1972?

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Anne Mellinger, M.D., M.P.H., Radiation Studies Branch, Division of Environmental Hazards and Health Effects, National Center for Environmental Health, Centers for Disease Control and Prevention

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Finding an association (or a link) between an exposure and a disease does not always mean there is a causal relationship (that is, an exposure causes a disease). There may be other reasons for the association.

Public health scientists consider a set of eight factors (known as Hill's postulates) to be an important guideline for proving a causal relationship. First is the strength of the association: there should be more disease in the exposed group; the higher the rate of disease in the exposed group, the more convincing the association. Second, the association should be consistent, or repeatedly observed in different studies. Third is timing: does the exposure occur before the disease, and is the latent period similar to what is already known? Fourth, the association should be dose-related: is there more disease in people who are exposed to a higher dose? Fifth, the association should be biologically plausible, consistent with current biological theory. Sixth, the association should be coherent with earlier studies, not contradicting known facts. Seventh is experiment: does a "preventive" action actually prevent the disease? Eighth is analogy: do similar exposures cause similar diseases?

These eight factors are guidelines. They do not all have to be fulfilled, but the more that are, the stronger the evidence for causation. The overall picture is as important as each individual factor.

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Rudi H. Nussbaum, Ph.D., Northwest Radiation Health Alliance, Portland, Oregon

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Information needed: Urge downwinders to report on the basis of health questionnaires and their selected medical records. Assemble records from hospitals and clinics. Use regional hospital records for comparable farming areas not exposed to Hanford's releases, as a basis for comparison. This will not establish cause per se according to epidemiological standards. However, if the difference in rates between Hanford downwinders and other populations is large, it will certainly raise questions about a possible link. The mode for this research must include full participation of downwinders, such as described by Phil Brown in his article, "Popular Epidemiology: When the Public Knows Better" (Environment, Vol. 35, No. 8, October 1993).

Notes

1.The Hanford Environmental Dose Reconstruction Project is the only study estimating doses from radiation received by people exposed to Hanford's releases of radioactive materials. When using information from the Dose Reconstruction Project and other studies, readers should keep in mind that research results depend on a number of factors, such as the information available, and the methods and type of analysis used.

2. Fred A. Mettler and Robert Moseley, Jr. Medical Effects of Ionizing Radiation. San Diego: Grune and Stratton, 1985.

3. Elaine Ron et al. "Tumors of the Brain and Nervous System After Radiotherapy in Childhood." The New England Journal of Medicine; Vol. 319, No. 16, 1988, pp. 1033-1039. Ron is a radiation epidemiologist at the National Cancer Institute in Bethesda, Md.

4. National Research Council. Health Effects of Exposure to Low Levels of Ionizing Radiation (commonly known as BEIR V–the report of the fifth Committee on the Biological Effects of Ionizing Radiation). Washington, DC: National Academy Press, 1990.

5. Shoji Tokuoka and Masayoshi Tokunaga. "Site-Specific Cancer Incidence: An Interim Report." RERF Update; Spring 1995, pp. 6-7. Tokuoka and Tokunaga are with the Department of Epidemiologic Pathology, Radiation Effects Research Foundation (RERF), Japan.

6. Desmond Thompson et al. "Cancer Incidence in Atomic Bomb Survivors, Part II: Solid Tumors, 1958-1987." Radiation Research, Vol. 137, 1994, pp. S17-S67.

7. BEIR V.

8. Mettler and Moseley.

9. Ron et al.

10. Mettler and Moseley.

11. Ron et al.

12. Lowell E. Sever et al. "A Case-Control Study of Congenital Malformations and Occupational Exposure to Low-Level Ionizing Radiation." American Journal of Epidemiology; Vol. 127, No. 2, 1988, pp. 226-242. At the time of this study, Sever was with the Division of Birth Defects and Developmental Disabilities, Center for Environmental Health, Centers for Disease Control in Atlanta, Ga.

13. Lowell E. Sever et al. "The Prevalence at Birth of Congenital Malformations in Communities near the Hanford Site." American Journal of Epidemiology; Vol. 127, No. 2, 1988, pp. 243-254.

14. Victor Alexander. "Brain Tumor Risk Among United States Nuclear Workers." Occupational Medicine: State of the Art Reviews. Philadelphia: Hanley and Belfus, Inc., Vol. 6, No. 4, October-December, 1991, pp. 695-714. Alexander is a researcher with EnviroMedicine Associates in New Orleans, La.

Further Reading

HHIN Publications

Genetic Effects and Birth Defects from Radiation Exposure, Fall 1994

The Immune System and Radiation, Summer 1994

Radioactivity in the Body, Spring 1994

Published Fall 1995

A PUBLICATION OF THE Hanford Health Information Network

Perspectives on the Hanford Thyroid Disease Study

CONTENTS

K. F. Baverstock Betty Bergdahl Bill Burke Tim Connor William Farris F. Owen Hoffman Larry Jecha Judith Jurji Duncan Thomas For More Information Summary: HTDS Draft Final Report (CDC)

This information sheet provides the viewpoints of scientists and citizens on the Draft Final Report of the Hanford Thyroid Disease Study (HTDS). The Centers for Disease Control and Prevention (CDC) made the draft report public in January 1999. CDC invited public comment and requested the National Academy of Sciences (NAS) to provide scientific peer review. The NAS is expected to provide a report of its scientific peer review in the fall of 1999.

For a summary of the HTDS preliminary results and background information on the study, see the information sheet provided by the CDC.

Many callers to the Hanford Health Information Network (HHIN) had questions about the HTDS draft report, what the results might mean and what questions have been raised about the report. To respond to these questions, the Network asked nine people with different areas of expertise or interests for a brief statement of their views on the draft HTDS report. To spur their thinking, the Network suggested four questions:

1. What issues, if any do you see that are raised by the draft HTDS report?

2. What, if anything, do you think should be done to follow up on this study?

3. The HTDS report was released in draft form to make the results available to the public as soon as possible and to provide opportunity for comment. What comments do you have on the release of the study in draft form and/or on the process of announcing the draft report?

4. What do you see as the significance of this study? (Or, how would you place the study in context for our readers?)

Those who contributed to this information sheet had the option of responding to these questions or focusing on their area of expertise or their concerns. Each contributor was asked to write for the general public. Network staff edited the statements for ease of understanding and added a glossary of key scientific terms. Each contributor approved the final edited version of his or her statement.

K.F. Baverstock

First I want to stress that the comments below represent my views as a scientist and should under no circumstances be taken to represent the views of the World Health Organisation.

I have read the introduction and executive summary of the draft HTDS report. Full details of the results and methodology (in particular how doses were calculated and distributed and how confounding due to exposure to the Nevada Test Site [NTS] fallout was dealt with) are not given there, so I cannot provide a final view on the implications of the report's negative findings. However, I am surprised that the investigators thought that a study on the scale reported (3,441 study participants) would provide the information they claimed to seek, namely evidence of a dose-response relationship.

However, in my view, a case could be made that HTDS found an excess of thyroid cancer cases in the study population. There are certainly more cases detected than would be expected on the basis of the national rates for invasive thyroid cancer. This excess is not necessarily the result of the exposure to radioiodine (there are other possible explanations), but I am surprised that the investigators do not address this issue in the executive summary before concluding that there is no excess of disease.

The criterion adopted by HTDS for detecting excess thyroid cancer due to iodine-131, namely that a "dose response" is evident, is much more demanding than detecting an excess of thyroid cancer in the population. This will be especially the case where individual doses are uncertain and where there have been other exposures, such as from the NTS, which may also induce the disease. These are both factors relevant to the HTDS. Detecting an excess is not absolute proof of causation by iodine-131 (for example, national rates may not be appropriate due to the design of the study). However, it is at least a potential indicator of effect and should be addressed before an excess of thyroid cancer is discounted.

I am, therefore, surprised that the report concludes so firmly that there is no increase in thyroid cancer. It may indeed be that there is no evidence of an increase. But, on the basis of this study, that is not, in my view, evidence for no increase.

K. F. Baverstock, Ph.D., has led the Radiation Protection Programme at the World Health Organisation European Centre for Environment and Health in Rome, Italy, since its founding in 1991. This program was instrumental in bringing to world attention the increase in thyroid cancer in Belarus, now attributed to the Chernobyl accident. Prior to 1991, Dr. Baverstock was at the UK Medical Research Council Radiobiology Unit where he pursued a wide range of scientific research interests related to the public and occupational health aspects of exposure to ionizing radiation. He has served on the oversight committee for a Nationwide Radiological Survey of the Marshall Islands and on the Committee on Exposure of the American People to Iodine-131 from Nevada Atomic-Bomb Tests. Ph.D., has led the Radiation Protection Programme at the World Health Organisation European Centre for Environment and Health in Rome, Italy, since its founding in 1991. This program was instrumental in bringing to world attention the increase in thyroid cancer in Belarus, now attributed to the Chernobyl accident. Prior to 1991, Dr. Baverstock was at the UK Medical Research Council Radiobiology Unit where he pursued a wide range of scientific research interests related to the public and occupational health aspects of exposure to ionizing radiation. He has served on the oversight committee for a Nationwide Radiological Survey of the Marshall Islands and on the Committee on Exposure of the American People to Iodine-131 from Nevada Atomic-Bomb Tests.

Betty Bergdahl

Impressions of the HTDS Findings

I am impressed with the thoroughness of the findings. This study has taken nine years, covered an area of 7,500 square miles, which includes Benton, Franklin and Adams Counties. A total of 4,875 individuals were interviewed including those born during 1940-1946. The majority of these people went to thyroid clinics, had thorough thyroid examinations, and were questioned about their past history of thyroid disease.

Two recognized groups were involved in the study-CDC and the Fred Hutchinson Cancer Research Center. To me, this makes the study legitimate and objective.

Issues Raised or Addressed by the Study

We have had articles in the Tri-City Herald and "Letters to the Editor," one right after another, about the people in this area who were concerned about the radionuclide emissions of iodine. I am sure that it must have been a decided relief to them to read the results of this study and to know there was not this concern.

Uncertainty over possible health effects seems to be less of an issue when the findings are examined. I am sure that many people had built up in their mind things that maybe were happening or were going to happen. From that standpoint, the findings have done a good job.

However, there is uncertainty for individuals born between 1940-1950 who now have thyroid disease. Was this caused by Hanford iodine released during 1944-1957? There are questions concerning infant mortality, fetal death and pre-term birth which may be answered when this study is completed later.

What, if anything, should be done to follow-up on the study?

CDC should continue to study the development of thyroid disease and implement public education outreach programs. The public can be alerted to signs of thyroid disease by public health agencies and health care providers. The results of the data on infant mortality, fetal death, and pre-term birth should be fully explained. Those are very important things to mothers and mothers-to-be. This should be settled so that there is an understanding of what the studies have proved on these issues.

The results of this study were released to the public before they were finalized. What are some positives and negatives of releasing the findings of a study early?

On the positive side, early release gives the highly interested public an opportunity to learn the results of the study at an early stage. This emphasizes the policy of complete openness and the intensity of the study. It shows that they want to keep the public current with what is going on at CDC.

What do the results of this study mean for you and your family?

As to us personally, I feel happy to know that there is no one in our family who has any concern about the thyroid. Our family grew up here and played in the river because we lived on the riverfront. This study was worthwhile because it has been a real concern for many families, while it wasn't a direct concern to us. I am sure that there are other parents who were worried about what might happen. For this reason, it is excellent that the study is completed and is being made public.

Betty Bergdahl has resided in Richland, Washington, since June 1943. She grew up in southeastern Washington state. She came to Richland when her husband began working at Hanford. Their first child was born in Dayton, Washington, in April 1943, two months before they moved to Richland. Between 1944 and 1948, the Bergdahls had three other children. The childhood and high school years of all four children were spent in Richland. The Bergdahls' home is on the riverfront of the Columbia. From May to October, the family and their friends lived on the dock, played on the river bank, camped on the islands, and sailed, water skied, and swam in the river. has resided in Richland, Washington, since June 1943. She grew up in southeastern Washington state. She came to Richland when her husband began working at Hanford. Their first child was born in Dayton, Washington, in April 1943, two months before they moved to Richland. Between 1944 and 1948, the Bergdahls had three other children. The childhood and high school years of all four children were spent in Richland. The Bergdahls' home is on the riverfront of the Columbia. From May to October, the family and their friends lived on the dock, played on the river bank, camped on the islands, and sailed, water skied, and swam in the river.

Bill Burke

There is a lot of thyroid disease reported on the Umatilla Indian Reservation. When I learned about the HTDS and iodine-131, I was immediately concerned. I was born in 1930. Many in my generation have thyroid disease. My children's mother had thyroid disease and was of an age to be affected by iodine-131.

Indians live close to the land and the river, and have traditionally eaten natural foods. This gives us unique exposures to the radionuclides released from Hanford.

We talked a lot about HTDS in the Native American Working Group. (The Native American Working Group coordinated Hanford-related Tribal research and recommended research activities to the Technical Steering Panel that directed the work of the Hanford Environmental Dose Reconstruction Project.) We thought that the Thyroid Disease Study would provide specific results about affected Indian Tribes. But in the end, we learned that our Tribal population was too small for epidemiologic study methods to give us a true picture of how our health was affected by the radionuclides.

There needs to be a study of thyroid disease in Tribal people. I am really interested seeing if ANOVA, or "analysis of variance" (a statistical method for detecting differences in the average of a factor such as dose or estimated risk, between groups), could be used to calculate ranges of risk with uncertainty for Tribal populations. Why not look at health risks to Tribal people using this or another alternative method?

The U.S. government has a real responsibility to understand Hanford-related health issues, including risks to the health of Tribal people. Under pressure from westward expansion, the Columbia Basin Tribes and Bands ceded many millions of acres in present-day Washington, Oregon and Idaho to the United States. Reservations were formed. Treaties established special legal responsibilities or trust relationships between the U.S. government and Indian nations. For example, Tribal leaders reserved rights to pursue their traditional lifestyles on ceded lands. Agreements between the United States and the Tribes are government-to-government commitments. But the trust relationships and the Tribes very often are overlooked. This seems to be the case here, too. It's very troubling.

I think a lot about the post-colonization trauma (PCT) that Native American people have experienced. Like post-traumatic stress syndrome, it describes the shock and confusion that follow an overwhelming event outside the range of human experience, such as combat or a natural disaster. It makes protecting our culture and the trust issue more meaningful to me as a Tribal leader. I don't understand-or maybe I do understand-the continuing attempt to take Indian lands. Understanding the effects of PCT made me feel more strongly about trust relations.

Today we still don't have any definite answers about the effects of the radionuclides released from Hanford into the air and into the Columbia River. All we know about radionuclides is, you can't see them, hear them or taste them-but they can affect us.

Bill Burke is one of four chiefs of the Confederated Tribes and Bands of the Umatilla Indian Reservation and one of two Walla Walla Chiefs. He is a past member of the Native American Working Group and the Hanford Health Information Network Tribal Advisory Board. Mr. Burke has served on the Future of the Hanford Site Lands Committee and the States and Tribes Government Working Group. is one of four chiefs of the Confederated Tribes and Bands of the Umatilla Indian Reservation and one of two Walla Walla Chiefs. He is a past member of the Native American Working Group and the Hanford Health Information Network Tribal Advisory Board. Mr. Burke has served on the Future of the Hanford Site Lands Committee and the States and Tribes Government Working Group.

Tim Connor

The Hanford Thyroid Disease Study Has Done More Harm Than Good for Hanford Downwinders

A decade ago, I was one of the people who worked very hard to gain Congressional support for a health study of people exposed to radioactive iodine emissions from Hanford. At the time, we believed such a study could provide a valuable public service for Hanford downwinders.

Regrettably, given the way in which the draft results of the study were communicated, the HTDS actually inflicted a good deal of harm on those whom the study was intended to serve.

The cause of this harm is not the fact that the HTDS investigators found no link between Hanford radiation and thyroid disease. The fact is, it is rare for individual epidemiologic studies to provide strong evidence for connections between low-dose exposures and diseases like cancer. More often than not, the results are inconclusive.

The problem with the January 1999 release of the HTDS is that the draft results of the study were presented as if they were conclusive. The message from the researchers was that if you are among those who suspected (or believed) that Hanford emissions are responsible for an increase in thyroid disease among downwinders, you should be "reassured" that there is no such connection.

Such statements by scientists are practically unheard of in connection with environmental epidemiologic studies. The simple reason for this is that scientists understand that the results of any such study (whether it finds a link, or doesn't) have to be viewed as a piece in a larger puzzle. This is because environmental epidemiology is not laboratory science where researchers conduct carefully controlled experiments that can be repeated by other scientists. It is an observational science, where a given hypothesis must be tested via repeated observations and evaluated within the context of animal studies, cellular and molecular research, etc.

In the case of the HTDS, there is considerable evidence from previous studies that exposure to radioactive iodine does cause increases in thyroid diseases. Why the HTDS team would offer "reassurance" in light of this other evidence is puzzling. The mildest criticism one can offer is that their statements do not reflect the circumspection and caution that is the hallmark of the science.

This basic problem with the way the HTDS results were reported is compounded by the several technical criticisms of the study. The most important technical criticism is that the HTDS was a "low power" study rather than the "powerful" study asserted by its authors.

What does this mean? In simplest terms, statistical power is a measure of confidence. The higher the power of a study, the less likely it is that a true cause/effect relationship will be missed. Conversely, a low-power study is one where the lack of an observed link between cause and effect has little, if any, meaning.

If the scientific critics of the HTDS are found to be correct, it will come as little, if any, consolation for Hanford downwinders. Not only has the HTDS left them more confused than ever. It has also left them feeling more betrayed than ever.

Tim Connor is the founder and Editorial Director of the Northwest Environmental Education Foundation. Previously, he was Associate Director and staff researcher for the Energy Research Foundation, a public interest foundation based in Columbia, S.C., where his work focused on health and environmental research. Before joining this organization, Mr. Connor was research director for the Hanford Education Action League, a public interest organization that was based in Spokane, Wash. Prior to his public interest work, Mr. Connor was an investigative reporter. He is the author of Burdens of Proof: Science and Public Accountability in the Field of Environmental Epidemiology, with a Focus on Low Dose Radiation and Community Health Studies (Energy Research Foundation, 1997).

William Farris

The HTDS relies on radiation dose estimates that were produced through a six-year study called the Hanford Environmental Dose Reconstruction (HEDR) Project. The HEDR Project, which was completed in 1994, developed detailed models and computer codes that could be used to calculate iodine-131 thyroid dose estimates for individuals, including HTDS study participants.

The HEDR Project was initiated because of public interest in the historical radioactive releases from the Hanford Site. Over 38,000 pages of documentation from the early years of Hanford operations were released to the public during 1985 and 1986. This information indicated that substantial quantities of radioactive materials had been released from Hanford. This information alone could not be used to reconstruct the actual radiation doses received by the population surrounding the Hanford Site. To accomplish that, a methodical reconstruction of the releases, environmental conditions and human activities was necessary. However, due to limitations in available data, it is important to note that the actual radiation dose received by any single individual will never be known with complete certainty. The radiation doses were not directly measured during the early years of site operations, so the use of predictive models was deemed necessary.

The primary purpose of the HEDR Project was to estimate the radiation dose using all existing information about the operations of the site, the knowledge about how radioactive materials are transported in the environment and the way in which people might be exposed to those materials. A system of computer models was developed to estimate radiation doses from atmospheric releases throughout the study area (eastern Washington, northern Oregon, and western Idaho). This system consisted of four separate but interrelated models and associated computer codes: source term (the amount and type of radioactive material released), atmospheric transport, environmental accumulation and individual dose.

The ability of scientists to recreate key events and conditions that existed 40 years in the past is limited by the lack of detailed data. Therefore, uncertainty estimates (that is, the range of possible estimates along with a most likely estimate) were included as a key component of the HEDR effort. For the first time on any dose reconstruction project, the individual radiation dose estimates included information about the uncertainty in those estimates. This was a major advance in the science of dose reconstruction. Uncertainties in the actual amounts released are addressed through use of multiple recreations (called realizations), each of which represents an alternative interpretation of the conditions that existed in the past and are consistent with existing knowledge. Together, these alternative conditions represent the range of conditions that could have existed.

One hundred separate realizations of the complete release history, environmental transport and human exposure assessment were performed to estimate the uncertainty in the model predictions. The reliability of the models was tested by reviewing the concepts underlying the models, testing the implementation of the models in the computer codes, analyzing the uncertainty and sensitivity, and validating the model output.

Extensive scientific peer review was conducted throughout the HEDR Project. Scientists and other stakeholders reviewed, critiqued and commented on the HEDR computer models as they were being developed.

Based on limitations in data, no model can ever hope to estimate perfectly the radiation impacts from Hanford. However, the science and models developed by the HEDR Project have proven highly reliable and provide for a sound technical base for Hanford-related individual dose assessments, including the HTDS.

William T. Farris is Program Manager, Environmental Technology Division, of Pacific Northwest National William T. Farris is Program Manager, Environmental Technology Division, of Pacific Northwest National Laboratory. Mr. Farris is an environmental health physicist specializing in the assessment of impacts of radioactive and hazardous waste disposal and restoration. He has degrees in geological sciences, radiological sciences and technology management. His experience includes public, worker and environmental health assessments that pertain to radioactive, hazardous chemical and mixed wastes. Past work includes the retrospective assessment of radiation doses from releases from the Hanford site. He served as Deputy Project Manager and authored the two final dosimetry reports for the HEDR Project.

F. Owen Hoffman

Issues in the Draft Report

The HTDS aimed to find a statistically significant relationship between increasing dose and the frequency of thyroid disease. Its failure to do so has been interpreted by the authors as being evidence of no effect (i.e., the negative findings are conclusive). I disagree. Because there could be a true underlying effect that cannot be detected by the study, I believe that the results of HTDS are, at present, inconclusive.

HTDS appears to be very well-designed, but the weakest link is the dosimetry (the method of estimating individual exposure and radiation dose). The individual estimates of thyroid dose are afflicted with relatively large uncertainty and the potential for bias. These dose estimates, which depend on the methods developed in HEDR, are calculated entirely using mathematical models. Few environmental measurements were available to permit calibration of the model against real-world conditions.

I believe it is likely that the individuals with high doses may have been overestimated, but those with the lowest doses may have been underestimated. The amounts of iodine-131 Hanford released after mid-1951 also appear to have been underestimated (raising the total curies released from about 750,000 to more than 900,000). Revision of the amount released would have a significant effect on the dose estimates for those who received low exposures to the high releases that occurred in 1945-46. Furthermore, an important confounder (a factor that could interfere with detecting a true effect) is the additional exposure to iodine-131 from the Nevada Test Site (NTS) and global fallout. These confounding exposures to iodine-131 were not given detailed consideration by HTDS.

The apparent negative findings of HTDS are at odds with other epidemiological studies, especially for people exposed in childhood. Studies of the Chernobyl accident, the nuclear tests at the Marshall Islands, and medical diagnostic uses of radiation show a strong dose-response effect for irradiation of a child's thyroid gland.

Why is HTDS inconsistent with other studies? I think the answer is a combination of the factors I have just mentioned: (1) the high degree of uncertainty in the dose model, (2) the confounding effects from NTS and global nuclear tests, and (3) HEDR's underestimation of Hanford's iodine-131 releases after mid-1951.

Release of the Study Results in Draft Form

In my view, the release of the HTDS draft report was not premature. I have always supported full disclosure of results, even when the results are in draft. However, the manner in which the draft report was released to the public (the formality of the release, the emphasis on pre-release secrecy) was certainly inappropriate. The preliminary nature of the HTDS findings should have been stressed more strongly and the possibility of the negative findings being inconclusive should have been discussed in detail. In retrospect, I believe that public representatives on the Hanford Health Effects Subcommittee and HTDS oversight committees should also have been briefed on the draft results prior to the U.S. Department of Energy (USDOE), Congress and the press.

Significance and Follow-up

The HTDS results show the need to look at exposures in a larger population, and at higher dose levels. It also shows the need for follow-up on the Chernobyl and Marshall Islands studies, since dosimetry for individuals in these cohorts is known with greater accuracy. In particular, the Chernobyl dosimetry is contemporary, and the exposed population is much better known and much larger than at Hanford.

HTDS is only one study; other studies show a dose-response relationship and have found risk for radiation-induced thyroid disease. The weight of evidence suggests that there is a risk for thyroid disease from exposure to iodine-131. In fact, I know of no compelling reason why the effect of exposure of the thyroid gland to iodine-131 should be substantially different from exposure of the thyroid to other types of ionizing radiation. Factors such as gender and age at the time of exposure should be more important than differences between exposure to iodine-131 and to external X- and gamma radiation.

The next step is to determine how much risk there is. Much of this determination will depend on epidemiological evidence obtained from careful study of other exposed populations.

F. Owen Hoffman, Ph.D., president of SENES Oak Ridge, Inc., is an expert in dose reconstruction and risk analysis. He has led the tasks to reconstruct thyroid doses to area residents from historic releases of iodine-131 from federal government facilities at Oak Ridge, Tennessee. Dr. Hoffman has advised dose reconstruction projects for the states of Tennessee and Colorado. He is a member of the National Council on Radiation Protection and Measurements and a corresponding member of the International Commission on Radiological Protection.

Larry Jecha

What issues, if any, do you see that are raised by the draft HTDS report?

I believe the HTDS report puts some issues to rest. This community (Benton and Franklin counties, which are the closest to Hanford) has not seen any increase in thyroid disease. We have the lowest rates of thyroid cancer in the state, and yet we had the highest exposures. The study results are consistent with what our medical community has observed.

What, if anything, do you think should be done to follow up on this study?

If anything, it might be useful to follow up on study participants, in terms of their ultrasound and fine needle aspiration tests, to see what happens to them over time. This follow-up could provide information on what the results of these tests really mean-which are normal findings and which are abnormal. At this time, there's no standard for interpreting these test results. This would not be follow-up related to radiation exposure but to the testing procedures that the study did.

What comments do you have on the release of the study in draft form and/or on the process of announcing the draft report?

I think the release of the results was premature, but it was a decision based on requests from interest groups. The plan, as discussed and approved by the HTDS Advisory Committee, had been to release the study results after peer review.

What do you see as the significance of this study?

The study verified what the medical community in our area has thought based on what they see in practice-that there is no increase in thyroid morbidity/mortality. Of all communities in Washington state, you would have thought our area would have been affected. Also significant is that this study has had more involvement by and with the public than any other study I have seen.

Larry Jecha, M.D., MPH, is the Health Officer for the Benton-Franklin County and Klickitat County Health Departments in Washington state. He served as chair of the Hanford Thyroid Disease Study Advisory Committee for all eight years of its existence. Dr. Jecha also chairs the Tri-Cities Health Care Task Force, is President-elect of the Benton-Franklin Medical Society and chair of the Washington State Public Health Executive Leadership Forum.

Judith Jurji

Birth of a Cynic

In retrospect it seems astonishing that there was so little early critique by health and science experts regarding the HTDS design. Certainly the public had its concerns. I remember the meetings where the study protocol was presented, and recall numerous people expressing dismay that the "control group" was in an exposed (albeit lesser) area, that the number of test subjects chosen seemed too small, and that attempting meaningful radiation doses was sure to be near impossible. All of this plain common sense fell, of course, on deaf ears.

In spite of their concerns, most of the affected population was supportive of the study, yet felt it was merely one item of many that needed doing. People wanted the government to deal with this health crisis in other ways. There was clearly a need for a system to medically monitor exposed people for radiogenic diseases and there was a need to provide health care if necessary. 

But what did we get? One expensive flawed study that took over a decade while everything else was put on hold. Unfortunately down-winders were not frozen in time. Diseases progressed, health deteriorated, and unnecessary deaths piled up. Public health officials looked the other way. Politicians saw no advantage in helping a scattered population that formed no identifiable voting block. Health physicists, with a few notable exceptions (such as John Gofman and Alice Stewart) busily defended the practices of the past. Denial was rampant and still is.

During this decade the USDOE was positioned legally and financially with enormous power to do the right thing. They did not. After years of serious citizen and scientific effort on the part of the Hanford Health Effects Subcommittee and federal health agencies to launch a medical monitoring and disease registry project, the USDOE snuffed it out like a tank crushing a flowerbed.

After 13 years of intense activism, I remain bewildered as to how the USDOE got so powerful and can remain so arrogant and irresponsible in a 20th century democracy. Although I believe the Thyroid Study was scientifically flawed as well as badly presented to the public with unwarranted certitude, yet I think the study team was, in fact, sincere in their efforts to answer an important scientific and health question. On the other hand, the USDOE has earned its place in history as the entity that used every opportunity to prohibit, curtail and block understanding of the toll to human health of the nuclear age. It might be added that the recent USDOE publicity about proposed programs in response to additional undisclosed worker exposures is clearly too late to help the many now-deceased workers. It appears to be all for show.

Judith Jurji is President of the Hanford Downwinders Coalition and a member of the Hanford Health Effects Subcommittee. She is also a founding member of the Advisory Board for the Hanford Health Information Archives. Ms. Jurji grew up in Kennewick, Wash., where her family moved in 1949. Her father worked at Hanford from that time until his retirement. She has been actively involved in Hanford-related health issues since the mid-1980s.

Duncan Thomas

My activities in the field of radiation and health include the Utah study of school children exposed to radioactive fallout from the Nevada Test Site (NTS). That study found associations between NTS exposures and leukemia and various thyroid diseases, mainly thyroid nodules. In the early days of this study, many of our peer reviewers wondered whether the findings were real or whether they were due to some methodological error or chance. It took hard work to convince people that the study was conducted correctly. The question of chance remains, but, in the end, even many critics came to believe that what we were seeing was real.

The HTDS results are different from those of the Utah study. The HTDS results are considered negative in that the study found no significant associations between increased dose and increased risk for any thyroid disease. But the question is similar. Are the HTDS results a convincing negative or are they due to a problem with methodology or with low statistical power?

Control Group

I believe that the HTDS researchers made a sensible decision to depend on internal comparisons. (In this case, study participants in Eastern Washington counties who were likely to have received the highest doses from Hanford were compared to participants in Eastern Washington counties who would have little or no dose from Hanford.) Most epidemiologists feel that using an internal control group within the study population is stronger basis for reaching a causal conclusion than an external control group methodology. It is very difficult to find an external control group that is comparable in all ways. With an external control group, you can't tell whether differences between the groups are due to real differences in exposure or to some other factor. Internal comparisons are a stronger basis for inferences about what a study's findings might imply for other similarly exposed populations.

If a study using both an internal and an external control group reached different findings for each method, I would tend to believe the internal control group. Exceptions to this are situations when there is not enough variation in the doses and when there is a lot of measurement error. For example, there is abundant evidence for an association between dietary fat and breast cancer from comparisons between countries, but this finding has been difficult to replicate in comparisons within a single population. While the international comparisons could be biased by confounding, it is also possible that some of the failure of the within-population comparisons could be due to insufficient variation of diet within populations or the difficulty of measuring long-term diets accurately. In this circumstance, some have argued in favor of external comparisons.

Uncertainty and Statistical Power

All estimates contain uncertainty. Uncertainty analysis is a statistical method for accounting for the lack of precise knowledge of a given estimate based on the amount and quality of the data. Uncertainty analysis is key to understanding whether or not the study's negative results could be due to random or systematic measurement error. Generally, random uncertainties will lower a study's statistical power and bias risk estimates downwards, but that bias can be removed if the uncertainties are correctly allowed for.

Statistical power measures the probability that a study can distinguish a true exposure-to-disease relationship from a coincidence. I have not studied HTDS's statistical power. I understand that HTDS researchers are still working on the uncertainty analysis for the dose estimates. This is important. The dose estimates were constructed with care but they are still estimates. However, I would be surprised if accounting for uncertainties in the dose estimates changed the negative result of the study to a positive result.

Measurement error tends to reduce the magnitude of association between dose and disease rates when there is a real relationship to begin with. I would expect that including the uncertainty analysis on the dose estimates will make the upper confidence limits higher, and the lower limits lower. In other words, it will broaden the range of risk estimates that are compatible with the data, but will not substantially increase the probability that they are significantly positive.

Duncan C. Thomas, Ph.D., is a professor in the Department of Preventive Medicine at the University of Southern California. He was an investigator for the Utah study of children exposed to radiation from the Nevada Test Site. Dr. Thomas served as a member of the National Research Council's Committee on the Biological Effects of Ionizing Radiation (BEIR V) which conducted a comprehensive review of the biological effects of ionizing radiation. He was also a member of the President's Advisory Committee on Human Radiation Experiments, whose report includes a chapter on the "Green Run" at Hanford.

For further information, contact HTDS in writing or by phone:

Hanford Thyroid Disease Study
Fred Hutchinson Cancer Research Center
1100 Fairview Avenue N., MP-425
PO Box 19024
Seattle, WA 98109-1024

Call toll-free: 1-800-638-4837

Summary of the Preliminary Results

THE HANFORD THYROID DISEASE STUDY DRAFT FINAL REPORT September 1999

Preliminary Results

On January 28, 1999, the Centers for Disease Control and Prevention (CDC) released the Draft Final Report from the Hanford Thyroid Disease Study (HTDS) which was conducted by the Fred Hutchinson Cancer Research Center in Seattle, WA, and funded by the CDC. This nine-year study evaluated whether or not the occurrence of thyroid disease was related to different levels of estimated radiation dose in a group of 3,441 people who were exposed as children to radioactive iodine (I-131) from the Hanford Nuclear Site during the 1940s and 1950s. This study was designed to investigate possible health effects of exposures to I-131 though other radionuclides were also released from the Hanford Facility. I-131 was the main radionuclide released from the facility and concentrates in the thyroid gland when inhaled or ingested. Therefore thyroid disease was the most likely health effect to occur in the population.

VISIT THE HTDS AND CDC WEB SITES

The complete text of the HTDS Draft Final Report and summary public information materials are available on the web at: www.fhcrc.org/science/phs/htds (The Fred Hutchinson Cancer Research Center's web site) . During the 5 month comment period (January 28 - July 1, 1999), CDC received 31 written comments on the Hanford Thyroid Disease. These comments have been posted on CDC's website. In order to maintain the privacy of individuals submitting comments we transcribed their letters verbatim, deleting only personal identifying information.

While thyroid diseases were observed among the HTDS participants, the initial study results did not show a link between the estimated dose to the thyroid from I-131 and the amount of thyroid disease in the study population.

Based on initial study results provided in the Draft Final Report, those who had higher estimated radiation doses appear to be no more likely to have thyroid diseases than those who had very low doses. (If study participants with higher estimated doses showed higher risk of thyroid disease, then that would provide evidence of a link between exposure and thyroid disease.)

These preliminary results do not mean that people living in the Hanford area during the 1940s and 1950s were not exposed to I-131 and other radionuclides, or that these exposures had no effect on the health of people living in the Hanford area. Although no link between estimated I-131 radiation dose and the amount of thyroid disease was identified by the HTDS in the study population, the study results do not prove that a link between I-131 and thyroid disease does not exist. There may be individuals in the overall population who were exposed to Hanford radiation and did develop thyroid disease because of their exposure.

Epidemiological studies are designed to examine large populations, and through analysis of levels of exposure and rates of disease, establish an association between exposure and the risk of disease in a general population. It is not possible in any epidemiological study to determine whether an individual person's thyroid disease is or is not caused by Hanford radiation exposure.

PUBLIC INVOLVEMENT AND EXPERT REVIEW

Since the beginning of the study, scientists at the FHCRC and the CDC have actively included other scientists and the public at every step in the study. This began with a series of public meetings in 1990 to inform the public and interested scientists on the study design. Copies of the study protocol, which outlined the plans for conducting the study were distributed to a number of experts and were made available to the public in area libraries. Many of the recommendations made during that process became part of the final study protocol. The first meeting of the federally chartered Hanford Thyroid Disease Study Advisory Committee was held in March 1991. This committee consisted of eight members representing areas of scientific expertise, environmental groups, the public, and Native American tribes. A consultant from the Hanford Downwinders Coalition was added a short time later. The study did not begin until this HTDS Advisory Committee, another committee at the FHCRC in charge of protecting the rights of research study participants, and the federal Office of Management and Budget approved the study protocol. The HTDS Advisory Committee met on a regular basis throughout the study, making recommendations to the CDC regarding the research plan and conduct of the study. In 1997, the HTDS Advisory Committee reviewed and approved the written HTDS Analysis Plan, a detailed document describing how the study would be analyzed. In February 1998, the HTDS Advisory Committee reviewed and approved a written HTDS Communications Plan, which described how the first available results from the study would be made public. Due to the high level of public interest in the results, the CDC and the FHCRC decided jointly to make the Draft Final Report available to the public while the peer review process was still underway, and before CDC or others made any revisions. The National Academy of Sciences' Committee on Assessment of CDC Radiation Studies also reviewed the HTDS Pilot Study Report and the HTDS Analysis Plan. Currently, the NAS is conducting a scientific peer review of the HTDS Draft Final Report. The results of their review are expected by late summer 1999. Suggested revisions and clarifications from all reviews will be incorporated into the HTDS Final Report.

Background

The HTDS was mandated by Congress in 1988, after the U.S. Department of Energy released documents showing that large amounts of I-131 were released into the air from Hanford, primarily during the late 1940s and early 1950s. Many area residents were concerned that their health might have been affected by the radiation from Hanford. Diseases of the thyroid (a small gland at the base of the neck that helps regulate growth and metabolism) were of particular concern because radioactive iodine inhaled or ingested by an individual concentrates in the thyroid.

How the Study Was Conducted

The Hanford Thyroid Disease Study was based on a group or cohort of 5,199 people born during 1940-46 to women who lived in any of seven counties of Washington State: Benton, Franklin, Adams, Walla Walla, Okanogan, Ferry, and Stevens. Starting with the birth certificates for this group, the research team tried to locate as many people as possible. A total of 4,875 (94%) were located. Those who could be contacted were invited to participate in the study. Because of these efforts, 3,441 people attended special HTDS clinics between 1992 and 1997, and provided information that could be used to determine their estimated thyroid radiation dose. At the study clinics, participants received thorough thyroid examinations by physicians experienced in the diagnosis of thyroid disease. They were also asked if they had any past history of thyroid disease. Pertinent medical records were obtained whenever possible to document and clarify past diagnoses.

Radiation dose to the thyroid was estimated for study participants based on information about residential history and factors such as milk consumption. Using this information, the study estimated thyroid doses using mathematical models that were developed by the Hanford Environmental Dose Reconstruction (HEDR) Project. This was a separate research project that investigated the releases of radioactive materials from Hanford, and estimated the radiation doses that people may have received as a result of exposure. Doses were estimated for the time period between December 1944 through the end of 1957 for individuals residing inside a region called the HEDR Study Area during any part of that time period. The HEDR study area consists of an approximately 75,000 square mile area surrounding Hanford. Results of the HEDR project indicated that people living in Benton, Franklin, and Adams Counties during 1944 (the year that the largest amounts of radioactive iodine were released from Hanford) most likely received the highest thyroid doses.

Of the 3,441 HTDS participants, 3,193 or (93%) had dose estimates calculated. Their estimated thyroid doses ranged from essentially zero to a maximum of more than 2,800 mGy (280 rad). (A mGy and a rad are units of radiation dose.) The average (mean) estimated dose among HTDS participants was 186 mGy (18.6 rad). About half of these 3,193 participants had doses over 100 mGy (10 rad), and only about 1% had doses over 1000 mGy (100 rad). The remaining 248 HTDS participants whose doses were not estimated never lived inside the HEDR Study Area between December 1944 and the end of 1957. Therefore, researchers could not estimate a thyroid dose for them. While this does not mean that they were completely unexposed to Hanford's radioactive iodine, their doses are believed to be very low.

Nine categories of thyroid disease were studied in the HTDS. Some individuals were diagnosed with more than one disease (for example, goiter and thyroid nodules) and are included in multiple disease categories. Nineteen confirmed cases of thyroid cancer (0.6%) were found among the 3,441 study participants. Five of the nineteen participants with thyroid cancer were among the 248 who never lived inside the HEDR Study Area between December 1944 and the end of 1957. Two hundred forty-nine participants (7.2%) had confirmed diagnoses of benign (noncancerous) thyroid nodules. Confirmed diagnoses of hypothyroidism and autoimmune thyroiditis were recorded for 267 (7.8%) and 648 (18.8%) participants, respectively. Thirty-four (1.0%) had confirmed diagnoses of Graves' disease. However, none of these diseases appeared to be significantly more common among study participants with higher estimated radiation doses than among those with lower doses. If there were a link between radiation dose and thyroid disease, we would expect thyroid diseases to occur more frequently in study participants with higher radiation doses.

In addition to thyroid diseases, the study evaluated whether three other outcome measures were related to radiation dose from Hanford's I-131: hyperparathyroidism; results of an ultrasound examination of the thyroid; and results of the blood tests related to thyroid and parathyroid function.

There was some indication that the proportion of individuals with small focal (individual) thyroid abnormalities detectable only by ultrasound increased slightly at higher doses. However, this increase was not statistically significant, meaning that it could have been due to chance. Small growth abnormalities of this type, which can be detected by sensitive ultrasound equipment but not by a physician during an examination, are very common in the general population. It is generally believed that most of these do not indicate thyroid disease.

The preliminary results of the study indicate that hyperparathyroidism was no more common in people with higher radiation doses from Hanford than those with very low doses. Hyperparathyroidism was evaluated using a measurement of calcium in the blood. Higher levels of serum calcium are associated with hyperparathyroidism. There was evidence from the study that the level of calcium in the blood (serum calcium) was slightly lower in people who received higher radiation doses from Hanford, but there was no increase in the proportion of persons with below-normal calcium levels in relation to thyroid radiation dose. Even among study participants with the highest doses, the levels of serum calcium were well within normal limits.

Evaluation of Mortality in the HTDS Study Population

Of the 5,199 people originally identified for inclusion in the study, it was determined that 541 were deceased. In an effort to see whether exclusion of these individuals from the study might in some way bias or influence the results, an investigation was undertaken to determine whether these deaths might be related in some way to thyroid cancer or other thyroid disease. Information from the death certificates was obtained for 502 of the 541 deceased individuals. An analysis of the causes of death revealed no indication that thyroid disease or thyroid cancer was responsible for any of these deaths.

However, some individuals may have had thyroid disease when they died. These cases of thyroid disease would not have been identified by the examination of death certificates. Overall mortality (death) rates in the HTDS study group were somewhat higher than what would be predicted based on mortality rates in the State of Washington for the same time period. In addition, there was an elevation in deaths related to birth defects, complications of pregnancy and delivery, and premature birth. Preliminary results from the HTDS indicate that the increase in mortality was evident before releases from Hanford began and continued after the Hanford facility started operation. The reasons for this higher death rate are not known. The HTDS was not designed to evaluate mortality in the population around the Hanford facility. Consequently, the amount of information that can be gained from this study about mortality is limited.

However, a study of infant and fetal deaths in eight Washington counties during the years 1940 to 1952 is currently being conducted by the Agency for Toxic Substances and Disease Registry with the results expected by late spring. Though the counties in the ATSDR study are different from those included in the HTDS, the study will provide additional information on rates of infant mortality, fetal death, and pre-term birth by geographic area. 


FREQUENTLY ASKED QUESTIONS ABOUT THE HTDS RESULTS

Q: Why was the study done?

The HTDS was conducted to find out whether there has been an increase in thyroid or parathyroid disease related to exposures from releases of radioactive iodine-131 into the air from the Hanford Nuclear Site in the 1940s and 1950s.

Q: What did the study find?

The initial study results provided in the Draft Final Report do not show a link between the estimated dose to the thyroid from I-131 and the amount of thyroid disease in the HTDS study population. While thyroid diseases were observed among the HTDS participants, those who had higher estimated radiation doses appeared to be no more likely to have thyroid diseases than those who had lower doses. Although no link between estimated I-131 radiation dose and the amount of thyroid disease was identified within the HTDS study population, the study results do not prove that a link does not exist.

In addition, these results do not mean that people living in the Hanford area during the 1940s and 1950s were not exposed to I-131. Nor do these results prove that these exposures had no effect on the health of people living in the Hanford area. There may be individuals in the overall population who were exposed to Hanford radiation and did develop thyroid disease because of their exposure. However, it is not possible in an epidemiological study like HTDS to determine whether an individual person's thyroid disease is or is not caused by Hanford radiation exposure.

While conducting the HTDS, researchers found that the death rates in the study population were slightly higher than predicted, based on death rates in the state of Washington for the same period, particularly due to birth defects, complications of pregnancy and delivery, and premature birth. Preliminary results from the HTDS indicate that the excess in mortality was evident before releases from Hanford began and continued after the Hanford facility started operation. The reasons for this apparent elevated rate in overall mortality are currently not known. However, a study of infant and fetal deaths in eight Washington counties during the years 1940-52 is currently being conducted by the ATSDR with the results expected by late spring.

Q: What if my dose was high?

The results of the study cannot rule out the possibility that an individual exposed to Iodine-131 from Hanford might have suffered some type of health effect as a result. No epidemiologic study is capable of doing so. If you are concerned about your health or the radiation dose you may have received, you should discuss your concerns with your health care provider.

Q: Were there other health effects from Hanford radiation releases?

The results of this study are limited to the effects of I-131 exposure and thyroid disease, associated laboratory tests and ultrasound results, and hyperparathyroidism in persons who were infants and children at the time of exposure. They do not answer questions about effects from other types of radiation released from Hanford, or other types of diseases in relation to Hanford exposures.

Q: Why were the study results released early?

CDC's commitment to conduct the study in complete openness, together with the intense interest about the study results on the part of the affected citizens, led to the release the Draft Final Report at this stage. The same public process has been used to release CDC reports at other nuclear weapon production sites.

The original HTDS Communications Plan, approved by the federally chartered HTDS Advisory Committee in February 1998, called for a report of the study results after the peer review process was complete. The purpose of this type of independent, expert peer review is to help ensure that the final results are accurate and complete. However, due to the high level of public interest in the results, the CDC and FHCRC decided jointly to make the Draft Final Report available to the public while the peer review process was still underway, and before CDC or others made any revisions. By doing so, all interested parties were given the opportunity to review the unedited findings at the earliest possible time.

Published November 1999
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