Nouvelles toxicités de l'uranium
GSIEN, New Scientist

ICRP model in trouble
     A New Scientist report on Uranium toxicity reveals a massive gap in the scientific modelling of the International Commission on Radiological Protection (ICRP). There are massive implications for all aspects of nuclear policy and Uranium weaponry.

"Secondary Photoelectron effect"
     The dangers of Uranium may have little to do with its inherent radioactivity. The Low Level Radiation Campaign's Dr. Chris Busby has proposed that genetic damage is caused by the interaction of natural gamma and other radiation fields with Uranium or any element of high atomic number. The impact of the gamma causes localised showers of ionisations close to particles and even single atoms of elements of high atomic number. Research by Busby in conjunction with Pr. Ewald Schnug, a colleague at Germany's Federal Agricultural Research Centre, is about to be published [see footnote].
All elements absorb gamma radiation and re-emit its energy in the form of secondary photo-electrons. Their ability to do this varies with the fourth power of the atomic number of the element; Uranium absorbs gamma rays 585365 times more effectively than water does. The shower of localised ionisations caused by the secondary photo-electrons creates a mechanism for genetic damage which is ignored by the conventional model of radiation risk. (The arithmetic is in LLRC's journal Radioactive Times April 2008 page 8:
     In 2003 Busby reported this "Secondary Photoelectron effect" to the British Government's Committee Examining Radiation Risk of Internal Emitters (CERRIE). It was one of the many important topics omitted by the CERRIE Majority Report. Subsequently Busby published two papers [see footnote] and described the effect to the UK Ministry of Defence Depleted Uranium Oversight Board and CoRWM (Committee on Radioactive Waste Management).
Heavy metal poisoning
     The New Scientist has discussed the Secondary Photoelectron effect only in relation to Depleted Uranium, although it has far wider relevance. It has potential to explain why heavy metals are toxic. Heavy metal toxicity exists despite wide differences in chemistry; until now no-one has understood the reason.
Uranium DNA affinity
     Uranium itself has a high affinity for the phosphates in the DNA molecule and it is known that, at small total body burdens of Uranium, a very high proportion of it will be on the DNA. Meditated by the Secondary Photoelectron effect, Uranium focuses the energy of natural gamma radiation onto DNA. This has the potential to explain observed high risks of genetic diseases associated with nuclear facilities and events like Chernobyl which are ignored by the ICRP and sneered at by the pro-nuclear International Atomic Energy Agency and the World Health Organisation (which has to defer to IAEA in matters of radiation and health).
Policy implications
     The mining, processing, use and disposal of Uranium must now be seen as creating health hazards far greater than predicted by the ICRP's out of date modelling. There are extremely important policy implications for nuclear power, disposal of radioactive waste, and nuclear weapons (including depleted Uranium and new generations of weapons containing other types of Uranium).
As LLRC has said since 1992, the effects of other types of radioactive pollution have probably been underestimated too, but it now seems that Uranium is the dominant problem.
New light on Busby's "Second Event theory"
     In the last 20 years Chris Busby has proposed his "Second Event theory" as a possible explanation of how radioactive elements that decay more than once (Strontium 90 is an example) may have a greater effect on genetic mutation. A first radioactive disintegration that hits a cell without killing it forces the cell to repair itself. If a second disintegration hits the same cell during the repair process, which takes a few hours, it may cause a mutation that the cell cannot repair. This is all in Wings of Death

     Supporters of nuclear power have attacked the theory, not least because they said radiation could not initiate the repair process in cells, but in the New Scientist article the ICRP's Hans-Georg Menzel accepts that "double hits of energy are known to be the most damaging to cells." The Majority Report of CERRIE denied this in 2004 after long arguments. See the Minority Report ( for the true state of the debate on the Second Event theory.
     The Secondary Photoelectron effect is now seen to be another case of the general Second Event theory, describing how sequences of radiation events can be concentrated into very localised cellular targets. These considerations make nonsense of the conventional model of radiation biology, which views radiation in terms of average energy transfer across large volumes of tissue. The old concept of "dose" is now useful only for those exposure regimes where the radiation truly is well-averaged. The regulation of radioactivity in the environment is about to enter a new phase in which "ionisation density" will be the vital parameter.
Compton scattering
     In the New Scientist article Mark Hill of Oxford University is reported as saying that Compton scattering would reduce the importance of the secondary photo-electron effect. However, Hill only discusses high energy gamma; the low energy part of the natural gamma spectrum will create relatively high ionisation densities with a correspondingly enhanced probability of causing double hits to DNA.
     The New Scientist article in full is only accessible to subscribers 
but it is free on

The Low Level Radiation Campaign plays a key role in all this. LLRC funds much of Dr. Busby's research. It was LLRC's publicity material that alerted Professor Schnug to Dr. Busby's existence, and our office put them in touch with each other. It was our journal Radioactive Times that alerted New Scientist to the imminent publication of Busby and Schnug's new paper.
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1. "Advanced Biochemical and Biophysical Aspects of Uranium Contamination". Chris Busby and Ewald Schnug: Institute of Plant Nutrition and Soil Science, Federal Agricultural Research Centre (FAL), Bundesallee 50, D-38116 Braunschweig, Germany in "Loads and Fate of Fertilizer Derived Uranium", pp. xx-xx Edited by L.J. De Kok & E. Schnug  © 2007 Backhuys Publishers, Leiden, The Netherlands
2  Busby C (2005) Depleted Uranium weapons, Metal Particles, and Radiation Dose European Journal of Biology and Bioelectromagnetics Vol 1 No 1 p 82-93
3. Busby C (2005) Does Uranium Contamination amplify natural background radiation dose to DNA?
European Journal of Biology and Bioelectromagnetics Vol 1 No 2 p 120-131