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Re: [Phys-l] Fact Sheet on the Three Mile Island Accident

At 09:56 -0400 04/09/2009, Spinozalens@aol.com wrote:

Health Effects

Detailed studies of the radiological consequences of the accident have been
conducted by the NRC, the Environmental Protection Agency, the Department
of Health, Education and Welfare (now Health and Human Services), the
Department of Energy, and the State of Pennsylvania. Several independent
studies have also been conducted. Estimates are that the average dose to about 2
million people in the area was only about 1 millirem. To put this into
context, exposure from a chest x-ray is about 6 millirem. Compared to the
natural radioactive background dose of about 100-125 millirem per year for the
area, the collective dose to the community from the accident was very
small. The maximum dose to a person at the site boundary would have been less
than 100 millirem.
In the months following the accident, although questions were raised about possible adverse effects from radiation on human, animal, and plant life in
the TMI area, none could be directly correlated to the accident. Thousands of environmental samples of air, water, milk, vegetation, soil, and
foodstuffs were collected by various groups monitoring the area. Very low
levels of radionuclides could be attributed to releases from the accident. However, comprehensive investigations and assessments by several well-respected
organizations have concluded that in spite of serious damage to the
reactor, most of the radiation was contained and that the actual release had
negligible effects on the physical health of individuals or the environment.

Bob,

I note that this is an excerpt from the NRC description of the TMI event on their web site. I cannot give it too much credence, for the following reasons:

1. All government agencies involved with ionizing radiation, from radioactivity through x-rays and other effects have consistently attempted to minimize the effects of radiation.

2. The agencies responsible for monitoring radiation (often the same ones that try to minimize its existence or effect), have consistently failed to do the job required of them, either keeping sloppy records, not recording needed data, poorly interpreting the data they have, ignoring it when it is convenient, suppressing the data through classification, or actively misrepresenting what they have. This has been pervasive throughout the government (aided and abetted by the commercial organizations who were trying to profit from activities that produced the radiation), ever since the first bomb test in 1945, including actively trying to keep the results of radiation effects studies of the Japanese hibakusha (bomb survivors) away from both the Japanese and American public, through censorship or classification of the data or both.

3. These same government agencies have for years attempted to convince the public that there is a minimum level of ionizing radiation, below which there is no damaging effect, or even that it is beneficial at sufficiently low doses. These concepts have been shown by epidemiologic studies to be totally false. There is no "safe" dose of ionizing radiation, only more or less damaging levels. They have tried consistently to label the officially "acceptable" doses as "safe" rather than that from which the damage is offset by the benefits. This has allowed many instances of damaging radiation to continue for years, leading to large numbers of unnecessary cancers among people who thought they were safe.

An example of the first reason can be seen in the quote form the NRC that you sent. The excerpt includes the passage "Estimates are that the average dose to about 2 million people in the area was only about 1 millirem. To put this into context, exposure from a chest x-ray is about 6 millirem. Compared to the natural radioactive background dose of about 100-125 millirem per year for the area, the collective dose to the community from the accident was very small. The maximum dose to a person at the site boundary would have been less than 100 millirem." The implication is that people received only 1 mrem of radiation, but, of course, some would have received considerably more--up to 100 mrem if the last sentence cited is to be believed. And the probability that any dose will induce a cancer increases linearly with dose (perhaps even supralinearly, but most epidemiologists use a linear relationship because it easier to calculate and the evidence for a supralinear relationship is not conclusive--what is conclusive is that the increase with increasing dose is not less than linear, in spite of claims to the contrary by industry representatives).

By emphasizing the size of the average dose relative to the background, they manage to imply that this dose *replaces* part of the background, rather than adds to it. It is important to remember that all radiation received that is not part of the background simply increases the total the person is exposed to. A small dose my not increase the cancer risk very much for any individual, but if the exposed population is large (as it was at TMI), the increase in cancer risk can lead to a measurable number of additional cancer deaths. The same thing is true of x-rays. Any x-ray exposure will increase the cancer risk to that patient, so the physician must weigh that risk with the diagnostic benefit the will be gained by having the x-ray made. It is also important that the patient understands this, and that the x-rays be made with the minimum usable dose to the patient (it is common for medical x-rays to use up to 10 times the necessary dose to obtain the needed information, mostly due to physician ignorance of the actual doses being delivered by the x-ray machine). All of these additional exposures to radiation add to that from the irreducible background and are cumulative over time. So spreading out a series of x-rays over several days or weeks does not reduce the cancer risk to the patient over that from doing them all in a short period.

The agencies responsible for monitoring radiation doses have consistently done a lousy job of carrying that responsibility out, often understating either the actual doses received or the actual effects of those doses that can be expected. Steve Wing, in his investigation of the effects of the radiation releases at TMI, found evidence of larger emissions than were ever reported by the official monitors at the time of the accident, whether that increases the average dose received by the population by a significant amount or not, it is clear that it increased the doses received by some by a considerable amount--enough to put those people at significant risk of cancer.

Often studies of post-irradiation cancer incidence are done within 3 or 4 years of the event, but the incidence of most cancers does not become significant before about seven years, and then continues for about 40 years beyond that, so a simply one-time count, especially early on, is usually not of much value. A complete estimate of the effects will need to take into account those cancers that have very late onset. In other words, to say that the death rate from cancer is such and such a value is pretty meaningless if there are still people living who might get cancer but have not yet. In other words, we can't always know who has been affected by a radiation accident until all those who were involved have died, from whatever cause. That doesn't mean we cannot make some forecasts, but it does mean that we can't say that since no one has died within, say, 10 years of the event, that no one will die in the future because of the event.

Another aspect of the radiation problem is that the standards which government agencies and commercial organizations use to address the risks to the public of potential or real radiation releases are based on what is known as the "reference man," a European male about 30 years old and weighing about 150 pounds. This standard has been in effect since it was created to enable exposure limits to be set for the nuclear industry, which was at the time almost exclusively made up of young white males. Exposure of the general public was not considered in establishing those standards, so the fact that women and children are up to 50% more susceptible to radiation-induced cancers was never considered. So when radiation limits are established, they rarely take into consideration that at least half the population will be more susceptible to the radiation than the part of it used to determine the limits. Both government and industry have consistently ignored efforts to create standards for those parts of the population most at risk from radiation.

So, all told, I think the evidence shows that we need to take any information regarding radiation that is released by any of the government agencies responsible for its monitoring with considerable skepticism, and that they are very unlikely to overestimate the effects of any radiation incident that they are involved with.

I wish this were not true, but it is clear that the governments of the world (not just ours) have been quite willing to sacrifice a certain percentage of their own population to support an energy industry of problematic value and weapons systems that have quite possibly been more destabilizing by their presence than they ever would have been by their absence.

Hugh
--
Hugh Haskell
mailto:hugh@ieer.org
mailto:hhaskell@mindspring,.com

So-called "global warming" is just a secret ploy by wacko tree-huggers to make America energy independent, clean our air and water, improve the fuel efficiency of our vehicles, kick-start 21st-century industries, and make our cities safer. Don't let them get away with it!!

Chip Giller, Founder, Grist.org