Revision 1
March 19, 1998
by Radiation, Science, and Health, Inc.,
Edited by J. Muckerheide

1.9
Conclusions

"Geologically, Brazil, a continental country, is characterized by presenting anomalies that create a significant variation in the exposure rates to which the public is submitted (Muckerheide1995, Luckey1996). As in other areas of the world, in which high levels of natural radiation occur, if biological effect exists, it is not, at present, sufficiently significant to allow its characterization through scientific methodology. The origin of biological effects of radiation begins with the transfer of nuclear energy carried by photons, alpha and beta particles, during the decay process, to electrons of atoms that constitute biological molecules. If the transferred energy of the nuclear particles is higher than the binding electron energy of the target atom, the electron will be ejected of its orbit, giving origin to a pair of ions and to the induction of biological responses, independently of the origin of the radiation: either anthropogenic or natural (Hendee 1996). According to ICRP, if the resulting effects of sub-clinical doses capable to induce deterministic effects are cumulative, public living in an environment with high natural radioactivity would present a previous disposition to develop stochastic effects, potentially and linearly with the accumulated doses. If this public has to be additionally exposed to radiation from human activities, the ‘problem’ would certainly be worsened. However, in the recommendations of ICRP, the base line for the management of doses in public considers both the individually accumulated doses and the accumulated doses through generations as non-existent. Within this context, the dose management is restricted in public to anthropogenic activities. Even for public exposed to high levels of natural radiation, what means a considerable amount of dose accumulated over generations, the National Nuclear Energy Commission, following the recommendations of ICRP, is equally restrictive, i.e., never takes into account if public is being exposed to a lower or higher level of natural radioactivity. Considering that biological effects result from interactions that happen, in an individual and aleatory way, at atomic level, in each one of the cell that receives the radiation energy, independently of the origin of this energy, if natural or anthropogenic, the position of ICRP, on a scientific basis, is not sustained: the adoption of the hypotheses of the linearity dose/effect and the absence of dose threshold would imply that the probabilistic previous disposition of damage coming from natural exposures should be considered in the effort to protect public against harmful effects of the radiation originated from anthropogenic activities. The non inclusion of doses accumulated due to the natural radioactivity in the risk assessment is a strong indication that even adopting the hypothesis of the absence of dose threshold for probabilistic effects, aiming radiological protection, the ICRP has perfect knowledge that, in fact, the subject of the low doses continues open, with great probability that it does not result in any significant effect."

"Apart from the radiological protection principles, and its motivations, and analyzing the subject exclusively considering its scientific aspects, it can be stated that: (i) for doses lower than 200 mSv effects of radiation that result in damages to the health of individuals or public as a whole are not observed (Muckerheide1995, Higson1996) (ii) for accumulated doses much greater than 200 mSv, over a life time period, higher rates of neoplastic illnesses were not confirmed (Wei, Zha and Tao 1990). On the contrary, there is evidence that some benefit could result from exposure to significant doses of radiation (Jaworowski 1994). Besides the conviction that ICRP has perfect knowledge of the lack of scientific consistency of its recommendations, the available evidence in the specialized literature does not seem to be sufficient to the authorities in the field of radiological protection to trigger the reviewing of more than fifty years of ‘well established’ posture. This situation reflects the isolation in which ICRP and correlated organisms have been maintained during decades. As a result, only few research institutions in the world have the knowledge on radiological protection. with only a small number of researchers having an idea of what ‘Sievert’ means. The great majority of laboratories qualified to investigate the relationship dose / effect and to define new approaches, other than the ‘well known’ epidemiologic studies, hereditary effects and cancer, believe firmly, corroborating the official position of the world authorities in radiological protection, that: (i) to any absorbed dose, a significant increment of probability is associated with the risk of cancer development and (ii) this is a definitive position. The claim for research in this subject drops into emptiness, since the radiological protection principles just reach professionals of this specific area for which the subject can be summarized by the sole observation of radiological protection guidelines."

"Facing the evolution of the subject, ICRP should take an aggressive attitude, placing clearly for the scientific community that the hypothesis of the linearity dose / effect is just a operational hypothesis, that was established in order to allow radiological protection to accomplish its purpose: the use of nuclear energy without risk for the health. It should be clarified however, that the same prudence that allowed the mentioned use can result in nonsense public rejection to all nuclear applications.

"In order to avoid total discredit of the exact sciences, with respect to their positioning about the effects of the low radiation doses, ICRP should also incentive scientists, not directly linked to the radiological protection subjects to contribute for the elaboration of radiological protection procedures. From now on, the radiological protection should be no longer based on hypothesis but on data obtained through scientific methods: elaboration of realistic hypothesis followed by experimental tests and finally, the thesis that should be the basis for a brand new philosophy for protection of public against the real risks associated with exposure to ionizing radiation."