Breaking News!! EPA Restricts Foreign Travel Because of Dangerous Radiation Levels

[Well, not yet really... but give them a little.]

The highest background radiation levels I could find are in China, India, Brazil, and Iran (more on this in chapter 17). All these countries have deposits of monazite - a black sand often found on beaches and in rare earth deposits - in which the principle radioisotopes are from the decay of thorium 232 and radium 226.

The 80,000 people of Kerala, India, receive up to 1,300 mrem (1.3 cSv or about three-and-a-half times our background exposure) per year and have been recognized for their healthfulness compared with neighboring states. The 10,000 citizens of Guarapari, Brazil, and the vacationers that flock to their beaches to bury themselves in the black sand absorb 0.03 mGy (3mrem) per hour - the equivalent of 26,280 mrem (2.6 cSv or about eighty-seven times our background) per year. [It is illegal to take the sand, but it has been done for centuries by tourists who have heard of its benefits and keep it under their beds. By so doing they receive little additional "through skin" radiation, but are exposed to continuing sources of breathable radon.]

Meanwhile in Ramsari, Iran, the 2,000 inhabitants and their ancestors have lived for centuries begin exposed up to 48,000 mrem (48 cSv or 132 times the U.S. average) and "survived" to tell about it... in fact they keep on surviving to the point that our regulators are wearing out their fingernails from scratching their LNT - and collective dose - heads. (Actually, they just engage in politically correct science: ignore those data that are inconvenient.)

Table 10 – Background Radiation in Various Locations with Comparisons
Case/Place	cGy/yr	mrem/year	Ratio to U.S. average
EPA level of concern	0.001	1	0.003
Limit nearby nuclear power plant	0.005	5	0.016
Proposed EPA maximum (all sources)	0.100	100	.3
U.S. average background	0.300	300	1.0
Chernobyl forced resettlement**	0.500	500	1.7
Colorado plateau	0.600	600	2.0
Kerala, India	1.3	1,300	4.3
Gerais, Brazil	2.3	2,300	7.7
Hormesis optimum (Luckey)	10.0	10,000	33.3
Guarapari Beach, Brazil	26.3	26,300	87.6
Ramasari, Iran (average)	48.0	48,000	132
* Adapted from “Radiation Hormesis for Health” by T.D. Luckey, Health Physics Newsletter, June 1995.
** In areas where the natural background plus the Chernobyl contribution exceeded this limit, 200,000 people were forcibly resettled.

You Can Run, But You Can't Hide

If an increase in low-level background radiation caused any problems, decades of anecdotal evidence would have made Denver a ghost town.

No one escapes radiation. As mentioned earlier, the average person receives 15,000 "hits" each second, while a medical X-ray may easily score some 100 billion cellular incidents. [Risk of Nuclear Power by Bernard L. Cohen, University of Pittsburg professor. You can read the entire article at http://www.physics.isu.edu/radinf/np-risk.htm.]

Those who say that "it takes only one gamma ray to cause cancer" may be technically correct, but they neglect to mention a small statistical detail: The odds against any particular gamma ray causing cancer in an affected cell are 1 out of 30,000,000,000,000,000. (That's 30 quadrillion, or 30 x 10^15, to one.) Besides, hormesis evidence indicates that the gamma ray of concern is more likely to prevent cancer than to cause it.

Before defining the units used to measure radiation exposure, you may recall we used the SXR (shoe X-ray) as a yardstick to compare the dangers posed by various radiation sources. As you may have guessed, the SXR is not exactly a reference unit recognized by the scientific community. A more convenient benchmark would be the average background exposure that we receive from the various natural and man-made sources. But, as we'll see, this "natural background" value varies by a factor of a hundred or so in different locales on planet Earth - almost all of which is the fault of nature, not man. Still, it would be desirable to reference other levels of radiation to some normal amount; so we'll arbitrarily use, as a definition of "natural background," the exposure to the average U.S. citizen - previously mentioned to be 300 mrem from natural sources and 63 mrem from man-made (mostly medical) origins.

Until the twentieth century, the average background dose of radiation for a human being had continually decreased over our specie's existence because of the slow decay of the primordial radionuclides such as thorium 232, uranium 238, and potassium 40. So what happened during the 1900s that turned the curve upward?

Most people would answer (a) fallout from atom/hydrogen bomb testing, and (b) nuclear power plants. Nice try, but no cigar. Bomb tests did inject huge amounts of highly radioactive materials into the atmosphere, where most decayed to safe levels within ten days of testing. Other longer-half-life isotopes from fallout caused a temporary worldwide increase of background radiation in the neighborhood of 1% to 4% depending mainly on location. [The one of primary concern being strontium 90 with a half-life of twenty-nine years and a propensity to replace calcium in bones.] Today it amounts to less than 1/1000 of the average background level. As mentioned, there has been only a single "fall-out fatality" from atom/hydrogen bomb testing, which occurred on the misnamed Lucky Dragon. While anti-nuclear statistics have killed off many (theoretical) thousands in their quest for an atomic scapegoat, our inaccurate friends have been unable to directly attribute any other death or injury to radiation from fallout, except as a statistical article-of-faith based on the discredited LNT and "collective dose" theories.

Nuclear power plants, on the other hand, have known emissions of radioactive products such as xenon (a non-reactive "noble" gas), but these are so low in practice as to be immeasurable. It is calculated that the average U.S. resident receives a dose considerably less than 1 mrem from all nuclear power plants combined - again, as with fallout, about 1/1000 of the normal background radiation. For those truly troubled by potential radiation exposure, it is not necessary to avoid being in the vicinity of power plants, but you might want to stay away from the U.S. Capitol building and Grand Central Station, both of which emit considerably more radiation than would be legal for any U.S. nuclear power plant to emit.

So where did the increase come from?

If we are to believe a report from the National Academy of Sciences Committee on the Biological Effect of Ionizing Radiation (BEIR IV), most of the increase came from weather-stripping storm doors, and polyethylene wrapping of new homes. Not that any of these products was unusually radioactive, but because they made houses "tight," thus causing radon gas, which bubbles up from decaying radionuclides in the soil, to be trapped in the living areas. This, they calculate, amounts to 200 mrem per year - unless, as well shall see, you are fortunate enough to get more.

The second largest component of the increase is from X-rays and nuclear medicine. The averages used for medically related exposures are somewhat misleading, however, since they range from a 1-mrem dental X-ray to about 100,000 mrem (100 cGy) for a thyroid ablation. [In 1979, the University of Michigan outfitted the husband of a woman undergoing radioactive iodine diagnosis with a dosimeter. They found that he received a dose of 2,500 mrem(!) during their vacation - which would no doubt cause the EPA to forbid them to sleep together.]

In other words, most people fall well below the combined 53 mrem medical dose, while a few have relatively massive doses. As the evidence section will show, even these huge doses of X-rays or medical radioisotopes produce no measurable increase in cancer - and indeed are seen to have a hormetic effect in those cases where low-level effects were investigated.

Finally, about 10 mrem comes from consumer products such as smoke detectors, television receivers, and tritium watch dials. None comes from the process of food irradiation for a very simple reason: The process physically can not make the food radioactive. Does having an X-ray make you radioactive? Same thing.

Table 9 gives a breakdown of sources in the United States, according to the BEIR committee. Obviously, for most of us, our largest dose of radiation comes from natural sources. The exposures from "man-made" sources are almost entirely voluntary. If you don't want to have a dental X-ray, then don't. If your doctor wants to check your thyroid function using iodine 131, tell him, "No thanks, I'll just feel awful for the rest of my life." If you don't want a smoke detector in your home, then don't buy one; burn your family up if that's your preference. Don't watch television or use a computer terminal.

Table 9
Sources of Average Annual Radiation for a U.S. Citizen
Natural Sources	mrem/yr	cSv/yr	% Total
Radon	200	0.2	55
Cosmic*	27	0.027	8
Terrestrial	28	0.028	11
Internal	39	0.039	11
Total Natural	300	0.3	82
Man-made sources
Medical X-rays	39	0.039	11
Nuclear medicine	14	0.014	4
Consumer goods	10	0.010	3
Nuclear power	< 1 **	< 0.001	-
Fallout	< 1	< 0.001	-
Total Man-made	63	0.063	18
TOTAL	363	0.363	100
* Doubles for every 6000 feet in altitude.
** The symbol “<” means “less than.”
Source: Department of Energy Report YMP-0337 from BEIR IV. Available in its entirety at http://www.ocrwm.doe.gov/factsheets/pdf/ymp0337rev1.pdf

But to avoid the natural background radiation, you need to take some pretty serious steps. Moving to Antarctica or living underwater in a nuclear submarine are your best bets. Or you could also move from high-background-radiation Colorado (with a low age-adjusted cancer death rate) to the low-background-radiation southeastern and eastern coastal states (with high age-adjusted cancer death rates). Then again, you might move out of your high-radon-exposure home in the Reading Prong of Pennsylvania to an area with a lower radon dose rate... but with a higher lung cancer toll.

You're not going to do any of these things. Why? Because if an increase in low-level background radiation caused any problems, we would see evidence - in the form of dead bodies. Decades of anecdotal evidence would have made Denver a ghost town, and Leadville, Colorado - the city with the highest altitude, therefore the most cosmic radiation - would have only monuments to its former short-lived citizens. But the only people who think that there is any such danger are the regulators, anti-nuclear activists, "environmentalists," and government scientists - who cling to the Linear No-Threshold (LNT) Hypothesis. We will be discussing this concept as applied to ionizing radiation, but since our government is so concerned about the doses we receive in this country, let's see what the situation would be if we lived with the background radiation experienced by fellow human beings who live in places outside the United States.

Remember, the average background radiation in the United States is 300 mrem (.3 cGy) plus an average of 63 mrem, primarily from medical sources. And remember that the radiation rules-makers are out to regulate public exposures down to a single mrem (.001 cGy); they intend to put a limit on public exposures at 100 mrem (0.1 cGy).

Hormesis Mechanisms

Every second the average person in the United States is "hit" by 15,000 particles of ionizing radiation, mostly from background sources. (The 1,500 "hits" mentioned earlier were only from cosmic sources.) Why does a relatively small increase in this exposure have a positive effect on the health of individuals? That physiological changes occur is unquestionable: it has been known for almost a century that low doses of radiation increase the production of lymphocytes (white blood cells). Other changes observed to occur are:

• Increased number of immune system helper T cells
• Decreased number of immune system suppressor T cells
• Increased activity of the p53 protein [a protein that reputedly decreases the incidence of many cancers]
• Increased free-radical scavenger activity (while radiation causes the creation of free radicals, it simultaneously produces much more of the remedy than of the problem).

The above, among others, are considered to be part of the cell's defensive system against chemical and radiation insults. Interestingly, high doses of radiation have a "reverse effect" on these very same cellular activities.

In the previous quotation from Dr. Rockwell, it was noted that a poor job in the cellular repair and removal business is what causes us potentially fatal problems. The body just doesn't do well with a bunch of sick, dying or dead cells hanging around. An interesting discovery resulting from the hormesis research led by Dr. Sohei Kondo was that low-dose radiation increased apoptosis - often referred to as altruistic cell suicide. [Dr. Kondo is professor emeritus of biology at Osaka University, and senior researcher at the Atomic Energy Research Institute, Kinki University, Osaka, Japan.]

By the process of apoptosis, damaged cells were absorbed without necrosis (a fancy scientific way of saying the cellular bodies were carted off before becoming offensive) and, at the same time, healthy cell replacement was stimulated.

In considering what hormesis is, we should also be aware of what it isn't. It is not the action of radiation on a single isolated cell. In experiments involving single cells in vitro [literally, "in glass," although almost all "glass" dishes these days are actually plastic], they behave as the LNT theorists would predict: the more radiation, the less vitality. [Critics of hormesis often point out isolated cell experiments as proof against the phenomenon.]

But when a society of cells, such as those making up an organ or an organism, is subjected to a relatively low dose of ionizing radiation, protective action (homeostasis) occurs, and the effect can be quite dramatic, as will be shown in the chapters on evidence.

One final analogy: we are aware that introducing the cowpox virus into our body causes the immune system to gear up and produce antibodies that also happen to be effective against smallpox. What isn't commonly known, however, is that inoculation against one disease increases the body's resistance to others. A 1986 English study showed a decrease in death from malignant disease for all who were inoculated, as children, for any one of eight diseases. Children inoculated against measles, for example, had a better chance to survive diphtheria or whooping cough, even while lacking those specific inoculations.

Similarly, low doses of radiation "inoculate" the body to the negative effects of future high doses - while at the same time appear to have positive effects in increasing general immune competency. Those who would like to learn more about radiobiological and hormetic effects should find the references in chapter 15 to be interesting. They allude to the Japanese research on the subject, which is well ahead of that being done in the United States.

A Day or So in the Life of a Cell

Hormesis is not the action of radiation on a single isolated cell. But when a society of cells, such as an organ, is subjected to low-doses of radiation, protective action occurs.
Hormesis, as discussed in Chapter 4, is the stimulatory action of a low dose of an agent that would be poisonous in larger amounts. Two of the questions that come to mind in considering the radiation hormesis phenomenon are:

How does radiation affect the body?
What physiological processes could cause the hormetic effect?

Circle the Wagons

Many of us have heard that the problem with radiation stems from radioactive particles smashing into our cells, breaking up the genes, crushing chromosomes, and mutilating the DNA - thus causing a cell to grow wildly out of control, which we call a cancer. (If you didn't think that, there must be something wrong with you, because that's what most people think.") When visualizing such cellular violence, I suspect that most of us have some kind of model in mind. Mine was a golf ball-sized alpha particle crashing into a basketball-sized cell, trashing pencil-sized chromosomes - all relatively speaking, of course. In the worst case, there was the dreaded "double-strand break," whereby a golf ball would slice through both pencil-like DNA strands, leaving the cell with no template by which to repair the damage, as it normally would do. Call the oncologist.

When I learned a little more about what goes on in a cell during its workaday world - which we'll be getting to shortly - my model just wasn't making much sense. So I decided to look at the relative sizes of cells and their atomic enemies in hopes of being able to better imagine the processes that were going on during the collisions. It was surprising.

Let us consider an average animal cell, which is about 20 microns (millionths of a meter) in diameter, and hypothetically expand its cross-sectional area until it is the size of the field in Yankee stadium. And then let's take an alpha particle - the shot put or bowling ball of the radioactive world - and enlarge it in the same proportion. [The nuclei of all atoms are surprisingly close to the same size. Uranium, while more than 200 times heavier, is only about three times as large as a hydrogen atom. The nuclei of both are on the order of one barn in cross-section, with the bar being 10^-24 cm2. (The term was occasioned when an early researcher remarked that a particular element's cross section looked as "wide as a barn.")]

What would you think? The alpha particle would be the size of a dump truck? A Volkswagen? (Too big.) A volley-ball? A baseball? (Too big.) A pea? A B-B? (Too big.) The alpha particle, in relation to a Yankee-Stadium-sized-cell, would be about 0.0003 inches in diameter - nearly the same as a human hair.

So what about damage inflicted by beta particles and gamma rays?

Beta rays are just speedy electrons, with 1/1836 the mass of any one of the two protons and two neutrons making up an alpha particle. In terms of mass, the beta "particle" is a ping-pong ball compared with a 7.3-pound alpha-particle brick. When piercing our Yankee-Stadium-sized cell, the wound would be invisibly small, even with a magnifying glass. Say, maybe our cells aren't necessarily such wimpy victims after all.

Gamma rays and X-rays consist of photons, which, though devastating when loaded in Star Trek torpedoes, are "packets," or quanta, of energy that have essentially zero mass and therefore, zero size. [If you really want to be picky, the photon can be considered to have a mass because of the Einsteinian equivalency between mass and energy. But the photon exists in the form of energy and not mass as we know it.]

Neither of these forms of ionizing radiation would make anything like a visible hole in our Yankee-Stadium-sized cell, but would pass through the cell walls like light through a dirty window.

With respect to the cell as a whole, radiation seems like mosquitoes attacking a circus tent, but once inside, high-energy particles or rays can wreak havoc upon individual atoms and molecules that make up our cellular structure. Alpha particles, protons, and neutrons scatter whatever is in their path, using their mass energy to separate electrons from their parent nuclei. Beta rays whiz through a thin layer of cells, knocking other electrons out of their orbits until their rather limited energy is expended. Gamma and X-rays act similarly, but with a vengeance proportional to their energies and inversely proportional to their wavelengths. [Light, which is part of the same electromagnetic spectrum as both X-rays and gamma rays, behaves similarly. Long wavelength infrared light - otherwise known as radiant heat - has very little energy compared to short wavelength ultraviolet light... which can "ultraviolate" you on the beach if you don't use sunblock.]

Usually they still have plenty of spunk after zipping through our bodies, stripping some 10,000 electrons out of their formerly contented orbits in the process.

Whenever an electron and its former nucleus partner (the proton) are separated, the atom is ionized - with the electron being a negative ion and the electron-starved nucleus being a positive ion. While we've been taught that the dreaded "double-strand breaks" are the main problem, the cell has a way to take care of these, which we'll get to soon. The primary cause of cellular damage from ionizing radiation is, by gosh - ionization.

When an electron is stripped away from a water molecule - and these make up some 99% of a cell's cytoplasm (the stuff inside the cell's membrane but outside the nucleus) - the normally placid water molecule turns into the Mr. Hyde of the cellular world. Good old H2O is converted into strange entities like hydroxyl radicals (OH-), which will fight anybody or anything to hook up with another electron. These are the feared "free radicals," which are the targets of heroic "anti-oxidants" seen in all health food magazines.

Just as I was completely off base on my concept of relative sizes of atoms and cells, I also had misconceptions about cell activities. I assumed they lived a rather boring life interrupted occasionally by having to split into two cells. From time to time, however, a bullet of radiation might penetrate the cell, causing it to marshal its defenses - for a battle that would often be lost - and an almost inevitable cancer would result. It's not a totally irrational model if you've been led to believe that all radiation is hazardous. But it's not even close to being true.

Just in case your cellular biology is a bit rusty, let's look for a moment at a typical animal cell. It is surrounded by a membrane that somehow knows what substances to let into and out of the cell. Inside the cell - besides cytoplasm - is the nucleus, which contains the nucleoli and the chromosomes. (The nucleoli busy themselves making the RNA and protein.) Chromosomes are long, threadlike bodies consisting of a single DNA molecule coiled tightly inside. In humans, the molecule is thought to be around sixteen inches long, but so thin that it cannot be resolved with an electron microscope. [In the Yankee Stadium example, the DNA molecule would be about 4,000 miles long but possibly too thin to be seen with the naked eye.]

Only about 10% of the DNA is active in providing instructions for the cell's growth, functioning, and reproduction. The remainder (essentially archives of the cell's history) is sometimes referred to as "junk DNA."

As far as being a peaceful environment, the cell makes a beehive appear to be laid-back. There are roughly 200,000 DNA repairs every day in every cell with some 30,000 unrepaired breaks existing at any given time. About 2% of these are the dreaded-double-strand breaks.

So most of this is caused by radiation? Hardly.

Normal oxidative damage - arising from thermal instability, replication, and free-radicals spawned by normal cell activities - is the overwhelming cause of DNA alterations. For the average U.S. citizen receiving a background dose of 0.3 cSv (300 mrem), the radiation-produced DNA breaks number six per cell per year. Even a fatal dose of 1000 cGy (1,000,000 mrad) produces only 20,000 breaks per cell - a mere 0.03% of the normally occurring 70 million altercations per year.

It would appear from this that radiation should have little effect on us one way or the other. Insofar as directly causing cancer, that is indeed what the evidence in future chapters will show. As Theodore Rockwell puts it:

"It is the repair and removal process (or lack of it) that kills us. Like other toxins, high-level radiation degrades those processes, but low-level actually stimulates them." [Ted Rockwell, Sc.D. is the former technical director of U.S. Naval Reactors. The American Nuclear Society's Lifetime Contribution Award has been named the Rockwell Award in his honor.]

As anyone with the least familiarity with radiation knows, high levels of radiation are dangerous and can kill you (Table 8). The low-level effects may be new to you, but they are real and are arguably far more important for society than the almost infinitesimally rare occurrences of high-level exposures.

Table 8 – Acute Radiation Syndrome
Subclinical Range 0 – 100 rads		Therapeutic Range 100 – 500 rads			Lethal Range 500+ rads
		100 – 200	200 – 300	300 – 500	500 – 2000	2000+
Appropriate Action	None	Clinical surveillance	Therapy effective	Therapy promising	Therapy palliative (comfort patient only)
Incidence of Vomiting	None	100 rads: 5% 200 rads: 50%	75%	75%	100%	100%
Delay Time	n/a	3 hours	2 hours	1 hour	3 min.	3 min.
Main Organs Affected	None	Blood Forming Tissue			Gastro-intestinal Tract	Central Nervous System
Characteristic Signs	None	White Blood Cell Decrease	Fatigue, infection, erythema, sterilization, loss of hair above 300 rads, hemorrhage		Diarrhea, fever, electrolyte imbalance, bleeding	Convulsion, coma, loss of muscle control, lethargy, tremors
Critical Period	n/a	n/a	4 – 6 weeks		5 – 14 days	1 – 48 hours
Post-exposure Therapy	Assure of Safety	Blood analysis; assure of safety	Blood transfusion; anti-biotics	Possible bone marrow transplant	Maintain electrolyte balance	Sedatives
Outlook	Excellent	Excellent	Good	Guarded	Hopeless	Hopeless
Convalescent Period	None	Several weeks	1 – 2 months	Long	n/a	n/a
Death Rate	None	None	0% - 40%	40% - 100%	90% - 100%	100%
Death Within	n/a	n/a	2 – 4 weeks		2 weeks	2 days
Cause of Death	n/a	n/a	Hemorrhage, infection		Dehydration	Respiratory failure; heart attack

A Very Short History of Radiation Hormesis

The extremely tall people on Niue Island (averaging height 6'6") receive 10 times more radiation from the soil than the world average. [Eugaster, Subradiation experiments concerning the concept of the natural radiation background, Aerospace Medicine, 35, 524, 1964.]

Why, you might logically ask, was the hormesis phenomenon not discovered until some eighty years after Roentgen, Becquerel, and the Curies made their contributions to radiation science? Why was there not an earlier Professor Luckey? [Professor Luckey is credited with coining the term "Radiation Hormesis" from his 1981 book Hormesis with Ionizing Radiation.]

Actually there was of sorts, and he, oddly enough, was also a professor at the University of Missouri. In 1896, Professor W. Shrader inoculated guinea pigs with the diphtheria bacillus. [Shrader, W. Experiments with X-rays upon germs. Electrical Engineering, 22, 170, 1896.]

The group exposed to X-rays prior to inoculation survived; the unexposed cohort died within twenty-four hours. Shrader, in the same series of experiments, was apparently the first person to discover that "Roentgen Rays" could be used to kill germs.

During the early twentieth century, radiation was used for a variety of experimental therapies, but the doses were generally far above hormetic levels and may well have caused more harm than good. Patent medicines such as "Radithor" (more on this in chapter 24) were popular, with single doses having nearly a million times the daily radium intake allowed by current government regulators. Hundreds of thousands of vials of elixirs were consumed without any widespread harm occurring and with a sizable number of "miracle cures" being reported. Few controls, however, were employed to scientifically assess the actual worth of the treatments leaving one to believe that most of these "cures" may have been either the product of advertising hype or a placebo effect.

Medical research wasn't the big draw for world-class physicists. We might remember that in the early days of radiation experimentation important discoveries were being made almost daily, while health considerations - except, possibly, for the annoying, minor and superficial skin "beta burns" - were considered to be of no consequence. The doses of radiation these unprotected experimenters received are estimated to exceed by thousands of times the maximums under which today's nuclear industry workers are allowed to continue on the job.

Madame Curie, discoverer of both polonium and radium, offers a good example of the "non-standards" of the day. [In 1516, a silver lode was discovered in St. Joachim's Dale (Joachimsthal), which was - naturally - confiscated by the government of Count von Schlick. Coins minted from this mine were known as Joachimsthalers, which (for obvious reasons) came to be known as thalers - in English, dollars. It was from this mine that the Curies obtained pitchblende - an ore rich in uranium and its daughters, radium and polonium.]

It is anecdotal that whenever Marie Sklodowska [in case you were curious why she named her first discovery for Poland] Curie walked into a room, electroscopes immediately discharged. [Gold is so malleable that it can be pressed into leaves less than 1/10,000 of an inch thick. If you hang two pieces of leaf in an air-filled jar, with provision to charge both - you have an electroscope. Charging the leaves with the same polarity causes them to "push apart" and, because they are so light, the electrostatic "pushing" force exceeds the gravitational force that would cause them to "droop" into a vertical position. Such devices were used to assay the content of uranium ores - not from the non-penetrating alpha radiation of the uranium, but from the accumulated daughters of which the gamma ray emitting radium was a significant component. Air, when ionized, is a conductor that discharged the electroscope at a rate proportional to the amount of ionizing radiation present.]

It is almost certain that she had an enormous lung burden of radium - the element she was extracting from uranium ore - which took quite a bit of patience, since there are only about 0.003 grams of radium per ton of ore. Madam Curie died almost certainly from the effects of long-term and extremely high doses of radiation. Yet, at age sixty-six, she still exceeded by ten years the life expectancy of her day.

Later in the century, the subject of hormesis would have doubtlessly been trifling compared to other matters. From August 1939 - when a letter from Albert Einstein was delivered to Franklin Roosevelt recommending the development of an atomic bomb - until the end of World War II, the focus of virtually the entire nulcear physics community became the Manhattan project. (This venture, equivalent in size to the total automotive industry at that time, is described in fascinating detail in The Making of the Atomic Bomb [Richard Rhodes, Simon & Schuster, New York, 1986].)

Certainly the scientists were aware of potential dangers from radiation - especially the highly penetrating neutrons from "atomic piles" - but these risks were minimal, compared with the reality of thousands of deaths from the war every day. Concerns about low-level radiation - either harmful or beneficial - weren't even on the radar scope.

Interestingly, the only health physics experiment I've ever come across that occurred during the Manhattan project was indicative of radiation hormesis:

"In 1943, a group of [radiation scientists] on the Manhattan District Project were worried about the unknown toxicity of uranium. They grew a colony of rats in an atmosphere laden with sufficient uranium dust to kill them fast (the Manhattan Project didn't have time for fancy radiobiologists). As a control, a similar colony breathed clean air. After several months, nothing happened, but eventually the rats lived out their natural lifespans, with one surprise: the first health physics experiment demonstrated that rats who breathed uranium dust lived longer and were happier (i.e., had a better reproductive history) than normal rats. Not a tumor in the bunch." [From a letter by Marshall Brucer, M.D. to Time magazine (from the files of Petr Beckmann).]

During this period there are reports of relatively minor medical experimentation to determine the effect of ionizing radiation on the healing of wounds. The exposure levels, however, were high (1 Gy or 100 rem) - suggesting its use as a bactericide. The availability of antibiotics in 1942, and the post-Hiroshima bombing concerns over high-level dangers, caused a loss of interest in research of this nature by the end of World War II.

After the war, the Japanese cities of Hiroshima and Nagasaki became laboratories for research on the effects of radiation on humans. But the focal point was on the high-dose subjects - in particular on their excess cancers and the possible mutational effects on children. When low-dose victims showed beneficial health effects, the data were ignored as being anomalies (a fancy scientific words for "it doesn't fit in with what we're expecting").

Luckey addresses this subject:

"Statistical analysis of observed data was missing in many reports of experiments involving low doses of ionizing radiation. Most of the reports simply indicated that an unexpected phenomenon had been observed, but the researchers failed to pursue it systematically... Any unexpected result was rejected by the 95% rule: One experiment in each twenty was accepted as a variant. Closer inspection showed this was a consistent result; it usually occurred in the group exposed to the least radiation, the only one in the hormetic range. Hormetic data were ignored because they did not fit the models of the zero thesis." [Radiation Hormesis, p. 45.]

When someone really writes a history of radiation hormesis, the first "official" recognition of the phenomenon will go to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in a 1994 report "Adaptive Responses to Radiation in Cells and Organisms":

"Manifestations of the adaptation described in mammals after exposure to low doses of radiation include accelerated growth rate in the young, increase in reproductive ability, extended life-span, stimulatory effects on the immune system, and a lower than expected incidence of spontaneous tumors."

You might want to read that again.

Hormesis U.: A Review

Before leaving dear old Hormesis U., here is a short review to see if you've got a handle on the curriculum. You should know...

• Elements are identified by the number of protons in the nucleus (atomic number).
• Isotopes of elements have different numbers of neutrons (n + p = atomic weight).
• Atoms of some isotopes are stable, while others are radioactive and, over time, will disintegrate (decay) into other elements of a lower atomic number.
• Alpha and beta particles have a short range (a few inches and a few feet respectively).
• Gamma rays and X-rays can penetrate several inches of steel or feet of concrete.
• The half-life of a radioactive isotope is the time it takes half of the original amount to decay; after thirty half-lives the original amount is considered to be gone.
• The longer the half-life, the lower the activity of an isotope.
• A curie is 37 billion becquerels.
• A pCi is a picocurie and is equal to one-trillionth (10^-12) of a curie.
• Absorbed doses of radiation are measured in rads or grays; 100 rads equal 1 gray.
• Biological doses are measured in rems or sieverts; 100 rems equal 1 sievert.
• The absorbed dose and the biological dose are the same for gamma and X-rays. 
• A fatal acute dose is about 4 sieverts or 400 rems (50% fatalities in thirty days) when received in a relatively short time (a few days or less).
• Radiation sickness occurs at about 1 sievert or 100 rems (50% of those exposed over a short time). 
• Doses below 1 sievert or 100 rems (100,000 millirems) have no immediate biologic effects but are generally thought to increase the risk of cancer in the future.

Thanks for your attendance at Hormesis U. No doubt you'll find the rest of the information on radiation hormesis much more understandable now than when you were a mere freshman. Oh, and be sure to send in your contribution to the Alumni Fund.