to be chafoin wrote:Since the discussion seems to be launched, I would like to clarify something in these discussions on the dangerousness of nuclear power. It seems that there are 2 types of impact to differentiate: the effects of excessive doses, and the effects of low doses. The latter are more complex to assess for various reasons and in particular because of the long-term influence.
But if we stay with the lethal aspect more or less immediate, the institutions which seem to be the only reliable scientific sources of certain defenders of nuclear power (I am not at all of this opinion but for the moment let us content ourselves with that), namely the IAEA, WHO, UN and UNSCEAR wrote in their press release of September 5, 2005 that the number of deaths caused by the exposure to the radioactive fallout from the Chernobyl disaster would reach the total figure of 4000. This total consists of:
50 workers who died from acute radiation syndrome in 1986 or from other causes in the following years;
de 9 children who died of thyroid cancer;
and an estimate of 3.940 people who could die from cancers contracted as a result of radiation exposure
.
pr_chernobyl_forum_050905.pdf
So if I am content with sources legitimized as the only valid by some, scientific experts recognize that the atom has been responsible for deaths and fatal cancers of the thyroid in children.
Which means :
1) that it is possible to give scientifically as the origin of cancer, exposure to radiation, contrary to what some claim.
2) that children died in Chernobyl, because of cancers contracted following exposure to radiation, contrary to what some claim.
Regarding the impact on animals and plants, the press release speaks of an increase in mortality among conifers, soil fauna and mammals in an area of 20 to 30km around the power plant.
Thank you chafoin for returning to a more convivial tone and rational speech. We need it…
In the field of radiotoxicity and the health effects of radioactivity, knowledge has grown enormously in recent decades, following the experience acquired during the three major accidents in the nuclear industry. It is essentially the WHO and UNSCEAR (organizations dependent on the UN, but not the UN) which have capitalized on the results of numerous studies carried out around the world. At the time of Chernobyl, knowledge on the effects of moderate but prolonged doses was known only by the studies consecutive with Hiroshima and Nagasaki, whose conditions of exposure (very intense brief flash engaging only small quantities of radioactive material (a few kilos)) were very different from those of Chernobyl (moderate but prolonged radioactivity, high amounts of radioactive material).
WHO and UNSCAER therefore produced an assessment report in 2005 (revised in 2016) which achieved consensus in the scientific community, while being contested by anti-nuclear organizations. This report quantified the number of deaths directly linked to the radioactivity released by the disaster at 59 deaths (including 15 deaths due to thyroid cancer), a figure revised in 2017 (62) and estimated, based on knowledge at the time ( therefore including the rule "linear without threshold") the number of long-term deaths of the order of 4000 (it was therefore not a measure, but a probability calculated from measured radioactive exposures and hypothetical laws). Epidemiological studies after 2005 did not confirm these forecasts of 4000, even showing paradoxical effects of lower incidence of cancers (except for a slight increase in leukemia) in exposed populations, in particular "liquidators". ; the study included 3 cases of death linked to the disaster ("deaths attributable" reliably "to the radiation produced by the accident") and pointed to a "psycho-social" pathology linked to the evacuation. Paradoxically, the people who had refused the evacuation or had returned very quickly appeared to be in better health than the evacuees.
The same organizations also published a study after Fukushima (faster because reliable data were available, unlike Chernobyl, considerably simplifying the investigation work). The conclusions are readily available on Wiki: “UNSCEAR found that the exposure of the Japanese population was low, with the consequence of low risks of health effects due to radiation later in life. This finding is consistent with the conclusions of the WHO report on health risk assessment. UNSCEAR had more data available after the period taken into account by WHO, which enabled it to make more precise estimates of doses and associated risks. ”
We will point out that:
- most of the proven Chernobyl deaths are not due to cancer (but to acute irradiation syndromes and skin lesions), with the exception of thyroid cancers, due to iodine 131, including etiology is well known.
- it is not possible, with certain exceptions, to determine the exact origin of cancer outside of epidemiological studies, which only provide collective estimates (precise, however); at the individual level, there is only one probability of risk.
- the various estimates (including those of anti-nuk organizations), in both cases, do not come from substantiated studies, but from summary calculations based on figures of people who are questionable, and based on hypotheses long since abandoned.
More generally, the risks associated with radioactivity are nowadays more and more precisely known; the risks linked to an intense but brief exposure are known (unfortunately) from Hiroshima (it was, unfortunately, one of the motivations for this bombardment) and are available on the internet; it is they who are at the origin of the rule "linear without threshold".
The risks associated with moderate but long-term exposure are very different and can be stated, simplifying a lot, as follows:
- a distinction is made between radioactivity generated by sources external to the human body, and radioactivity generated by internal sources (swallowed or inhaled elements); the consequences are significant, certain elements being completely harmless outside the body, but proving to be very radiotoxic inside (this is the case in particular of radon and iodine)
- "natural" radioactivity (cosmic radiation, soil, radio-diagnostic, internal, etc.) varies from 1mSv / year (in Paris for example) to 6 or 7 mSv / year in certain granite areas (Brittany, Limousin, Corsica, etc. ), or even 200 or 250 mSv in certain regions of the world (Iran, India, Brazil, etc.) without any increase in mortality or cancer having been measured between the various regions. On the other hand, under certain conditions, the toxicity of certain emanations of radioactive gases can be formidable; this is the case for radon (in a confined environment) or iodine 131 ...
- it appears that doses of radioactivity lower than 100 mSv / year (therefore almost 50 times higher than the usual doses, and authorized) have no measurable effect on human health; some say 200 mSv / year. 100 mSv / year is already much more than the maximum doses received by Fukushima workers…
- above 100, or 200 mSv / year, the so-called stochastic effects of radiation appear, that is to say the appearance of random or very real illnesses or damage, statistically measurable and varying with the dose received; it is essentially the area of radiation-induced cancers and genetic damage, established over the more or less long term.
- finally, beyond 1 Sv, appears the area of deterministic effects where there is certain induction of serious attacks (cancers, genetic mutations ...) then of fatal attacks in the short or very short term (doses of 1 Gray or more ).
In fact, in Fukushima, the maximum dose received by the workers involved did not exceed 25 mSv, which places these workers in an area where we are unable to measure a deleterious effect. Perhaps because we are still incapable of it, certainly. But scientific honesty consists in recognizing that no effect is measurable, and that we do not know the cause of the cancers appearing in these workers; if an epidemiological study showed that there are more cancers among these workers than in the general population, obviously, the responsibility for these cancers should be attributed to radioactivity; but that’s not the case today…
Regarding flora and fauna, I have no scientific study available; that said, the phenomenon of the "red forest" is well known and it seems certain that deciduous trees are more resistant to radiation; it's still a little light analysis.
Precisely, nothing convincing and must compare what is comparable, because in this case it was the prohibited area where the doses received were immeasurable. Educate yourself properly and stop seeing lobbies everywhere ... 
