The Chernobyl Nuclear Catastrophe: Unacknowledged Health Detriment

Referencing: The Chernobyl Accident 20 Years On: An Assessment of the Health Consequences and the International Response

Baverstock and Williams (2006) rightly recommended international long-term studies of all potential health effects among the populations exposed to Chernobyl fallout. In the meanwhile, data on post-Chernobyl health detriment in the former Soviet Union and exposed parts of Europe, including evidence of association with such contamination, are already accessible, mostly electronically. Three mutually consistent findings, in particular, challenge widely publicized conclusions the World Health Organization (WHO 2005a, 2005b) (after approval by the International Atomic Energy Agency), and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR 2000).

First, scientists from the Moscow Kurchatov Institute presented physical evidence that the dominant sources of energy released by the exploding reactor were not the officially assumed thermal explosions (Fairlie and Sumner 2006) but rather very low-yield nuclear chain reactions in heavy elements, combined with chemical reactions (Checherov 2006). Thus, contrary to the assumed emission of 50 million Ci into the atmosphere (i.e., an estimated 3.5% of the radioactive inventory of the destroyed fuel elements, leaving over 90% of it in the "sarcophagus"), these scientists conclude a 26-fold larger release of radioactivity, leaving no more than 10–15% of the inventory behind. A 26-fold increase would mean that population exposures from the worldwide fallout was in fact more than an order of magnitude larger than assumed by UNSCEAR (2000). This would explain a variety of observed health effects that are not to be expected at currently assumed doses (Committee Examining Radiation Risks of Internal Emitters 2004; Fairlie and Sumner 2006; Glushenko et al. 2006).

Second, the WHO accepted the conclusions by UNSCEAR that exposures of populations in the neighboring contaminated regions were of the order of 10 mSv, except for higher thyroid doses from ¹³¹I (UNSCEAR 2000; WHO 2005a, 2005b). The main contributions to dose in other tissues—externally and internally—have been assumed to come from ¹³⁷Cs and ¹³⁴Cs, whereas exposures from other radioisotopes, such as ⁹⁰Sr and ²³⁹Pu, or other alpha emitters were presumed negligible beyond distances of about 100 km from the plant (Fairlie and Sumner 2006; UNSCEAR 2000; WHO 2005a, 2005b).

However, direct biological dosimetry contradicts these official estimates. Several research teams investigated radiation-specific cytogenic alterations in the lymphocytes of about 1,000 exposed persons immediately after the accident and/or some years later (Schmitz-Feuerhake 2006; Schmitz-Feuerhake et al. 2006). The majority of these studies revealed that the rate of unstable and stable chromosome aberrations was about 10–100 times higher than would be expected at UNSCEAR's estimated exposure levels (UNSCEAR 2000). Biological dosimetry is, however, consistent with the evidence for a much larger release of radioactivity in the explosion. Furthermore, multiaberrant cells, characteristic for incorporated alpha emitters, were identified well beyond 100 km from Chernobyl, whereas plutonium particles were found as far away as Norway, contradicting "negligible exposure levels" beyond 100 km [International Physicians for the Prevention of Nuclear War (IPPNW) 2006; Schmitz-Feuerhake 2006; Schmitz-Feuerhake et al. 2006]. Currently adopted models for Chernobyl dose estimates ignore contributions from alpha emissions even though they are known to have relative biological effectiveness (RBE) about 20 times larger than that of most radioactive beta and gamma radiation (Fairlie and Sumner 2006; International Commission on Radiological Protection 1991; UNSCEAR 2000).

Third, excess infant (perinatal) mortality and teratogenic effects were observed in Germany, Poland, and the former Soviet Union shortly after the Chernobyl explosion [European Committee on Radiation Risk (ECRR) 2006; Gesellschaft für Strahlenschutz/ECRR 2006; Körblein 1997, 2003; Scherb et al. 1999; Schmitz-Feuerhake 2006]. Excess malformations, childhood morbidity, and genetic effects were reported from several areas of Central Europe and Turkey (Committee Examining Radiation Risks of Internal Emitters 2004; ECRR 2006; Fairlie and Sumner 2006; Körblein 2006; Scherb 2006; Schmitz-Feuerhake 2006). These post-Chernobyl observations are consistent with those in the United Kingdom, the United States, and West Germany following the atmospheric nuclear bomb tests of the 1950s (Körblein 2004; Whyte 1992). According to the International Commission on Radiological Protection (1991), UNSCEAR (2000), and other radiation authorities, teratogenic effects should not occur below a dose threshold of about 100 mSv. However, official estimates of fetal doses after the Chernobyl explosion, even in the most contaminated regions of Germany, were < 1 mSv (UNSCEAR 2000), far below the presumed safe threshold. Thus, either the fetus is much more sensitive to radiation than officially assumed, or the estimated post-Chernobyl fetal doses are far too low (which is consistent with considerably higher radioactive releases), or, most likely, there is a combination of both.

In the absence of scientifically convincing evidence rebutting such challenges to official assessments of the physical events and long-term human consequences of the Chernobyl catastrophe, the Precautionary Principle in public health issues (Goldstein 1999; Kriebel et al.2001) requires that these unwelcome findings be no longer ignored in "state of knowledge" reviews (Brenner et al. 2003; National Research Council 2006), in "assessments of the health consequences" (Baverstock and Williams 2006), and in official radiation protection standards.

The author declares he has no competing financial interests.

References

Baverstock K, Williams D. 2006. The Chernobyl accident 20 years on: an assessment of the health consequences and the international response. Environ Health Perspect 114:1312–1317.

Brenner DJ, Doll R, Goodhead DT, Hall EJ, Land CE, Little JB, et al. 2003. Cancer risks attributable to low doses of ionizing radiation: assessing what we really know. Proc Natl Acad Sci USA 100(24):13761–13766; doi: 10.1073/pnas.2235592100 [Online 10 November 2003].

Checherov KP. 2006. On the physical nature and parameters of the explosion (energy release of physical and chemical reactions in the accident processes development) in block 4 of the Chernobyl Nuclear Power Plant [Abstract]. In: International Congress: Chernobyl–20 Years Later. Berlin: Gesellschaft für Strahlenschutz/European Committee on Radiation Risks, 18.0–18.3. Available: http://www.strahlentelex.de/20_Jahre%20_nach_Tschernobyl_Abstracts_GSS_Berlin-Charite_2006.pdf [accessed 20 September 2006].

Committee Examining Radiation Risks of Internal Emitters. 2004. Committee Examining Radiation Risks of Internal Emitters (CERRIE) Homepage. Available: http://www.cerrie.org [accessed 20 September 2006].

ECRR (European Committee on Radiation Risk). 2006. Chernobyl 20 Years On; The Health Effects of the Chernobyl Accident. Aberystwyth, UK:Green Audit Press. Available: http://www.euradcom.org/publications/chernobylebook.pdf [accessed 20 September 2006].

Fairlie I, Sumner D. 2006. The Other Report on Chernobyl (TORCH). Berlin, Brussels, Kiev:Greens/EFA in the European Parliament. Available: http://www.chernobylreport.org/torch.pdf [accessed 6 April 2007].

Gesellschaft für Strahlenschutz/ECRR (European Committee on Radiation Risks). 2006. International Congress: Chernobyl–20 Years Later, Berlin, Germany, 3–5 April 2006. Available: http://www.strahlentelex.de/20_Jahre%20_nach_Tschernobyl_Abstracts_GSS_Berlin-Charite_2006.pdf [accessed 20 September 2006].

Glushenko AI, Suskov II, Baleva LS, Sipyagina AE, Checherov KP. 2006. The radiation-ecological and medical-genetic consequences of the Chernobyl disaster after 20 years and the prognosis for the future [Abstract]. In: International Congress: Chernobyl–20 Years Later. Berlin: Gesellschaft für Strahlenschutz/European Committee on Radiation Risks, 23–24. Available: http://www.strahlentelex.de/20_Jahre%20_nach_Tschernobyl_Abstracts_GSS_Berlin-Charite_2006.pdf [accessed 20 September 2006].

Goldstein BD. 1999. The precautionary principle and scientific research are not antithetical [Editorial]. Environ Health Perspect 107:A594–A595.

International Commission on Radiological Protection. 1991. 1990 Recommendations of the ICRP. Ann ICRP 21(1-3):1–201.

IPPNW. 2006. The Health Effects of Chernobyl. Meta analysis. Berlin:International Physicians for the Prevention of Nuclear War and Gesellschaft für Strahlenschutz. Available: http://www.ippnw-europe.org/ [accessed September 2006].

Körblein A. 1997. Perinatal mortality in Germany following the Chernobyl accident. Radiat Environ Biophys 36:3–7.

Körblein A. 2003. Strontium fallout from Chernobyl and perinatal mortality in Ukraine and Belarus. Radiats Biol Radioecol 43(2):197–202.

Körblein A. 2004. Perinatal mortality in West Germany following atmospheric nuclear tests. Arch Environ Health 59(11):604–609.

Körblein A. 2006. Infant mortality after Chernobyl [Abstract]. In: International Congress: Chernobyl–20 Years Later. Berlin:Gesellschaft für Strahlenschutz/European Committee on Radiation Risks, 35. Available: http://www.strahlentelex.de/20_Jahre%20_nach_Tschernobyl_Abstracts_GSS_Berlin-Charite_2006.pdf [accessed 20 September 2006].

Kriebel D, Tickner J, Epstein P, Lemons J, Levins R, Loechler EL, et al. 2001. The precautionary principle in environmental science. Environ Health Perspect 109: 871–876.

National Research Council. 2006. Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2. Washington, DC:National Academy Press. Available: http://www.nap.edu/books/030909156X/html [accessed 20 September 2006].

Scherb H. 2006. Statistical analysis of genetic effects after the Chernobyl disaster [Abstract]. In: International Congress: Chernobyl–20 Years Later. Berlin: Gesellschaft für Strahlenschutz/European Committee on Radiation Risks, 37–39. Available: http://www.strahlentelex.de/20_Jahre%20_nach_Tschernobyl_Abstracts_GSS_Berlin-Charite_2006.pdf [accessed 20 September 2006].

Scherb H, Weigelt E, Bruske-Hohlfield I. 1999. European stillbirth proportions before and after the Chernobyl accident. Int J Epidemiol 28:932–940.

Schmitz-Feuerhake I. 2006. Radiation-induced effects in humans after in utero exposure: conclusions from findings after the Chernobyl accident. In: Chernobyl 20 Years On; The Health Effects of the Chernobyl Accident. Aberystwyth, UK:Green Audit Press, 105–116. Available: http://www.euradcom.org/publications/chernobylebook.pdf [accessed 6 April 2006].

Schmitz-Feuerhake I, Hoffmann W, Pflugbeil S. 2006. How reliable are the dose estimates for populations contaminated by Chernobyl fallout? A comparison of results by physical reconstruction and biological dosimetry [Abstract]. In: International Congress: Chernobyl–20 Years Later. Berlin: Gesellschaft für Strahlenschutz/European Committee on Radiation Risks, 21. Available: http://www.strahlentelex.de/20_Jahre%20_nach_Tschernobyl_Abstracts_GSS_Berlin-Charite_2006.pdf [accessed 20 September 2006].

UNSCEAR. 2000. Annex J: Exposures and effects of the Chernobyl accident. In: Sources and Effects of Ionising Radiation; United Nations Scientific Committee on the Effects of Atomic Radiation. UNSCEAR 2000 Report to the General Assembly with Scientific Annexes. Volume II: Effects. New York: United Nations: 451-566. Available: http://www.unscear.org/docs/reports/annexj.pdf [accessed 6 April 2007].

WHO. 2005a. Health Effects of the Chernobyl Accident and Special Health Care Programmes. Available: http://www.who.int/entity/ionizing_radiation/a_e/chernobyl/-EGH%20Master%20file%202005.08.24.pdf [accessed 20 September 2006]

WHO. 2005b. Chernobyl: The True Scale of the Accident: 20 Years Later a UN Report Provides Definitive Answers and Ways to Repair Lives. Available: http://www.who.int/mediacentre/news/releases/2005/pr38/en/index.html [accessed 6 April 2007].

Whyte RK. 1992. First day neonatal mortality since 1935: re-examination of the Cross hypothesis. BMJ 304:343–346.

---

The Chernobyl Nuclear Catastrophe: Baverstock and Williams Respond

Nussbaum makes three points, namely that on the basis of the "source term" for the Chernobyl accident population, doses are underestimated by a factor up to 26, that Chernobyl dose estimates ignore exposure to alpha emissions, and that excess perinatal mortality and morbidity have been widely observed outside the main contaminated regions.

Nussbaum's first point is pivotal because it provides the rationale for the claims that the health effects of the accident have been underestimated. We are not aware that the source term has been used in the estimation of doses. It was not for the most affected areas (Fairlie and Sumner 2006). As far as Europe is concerned, doses from isotopes of iodine and cesium have been estimated from surveys of ground deposition. As recently as 2006, the doses for all of Western Europe and much of Central and Eastern Europe were reestimated by Cardis et al. (2006); there is reasonable agreement between their estimates and those made within a few years of the accident [e.g., United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 1988]. We, therefore, do not accept that population beta and gamma doses from iodine and cesium have been grossly underestimated.

We do not dispute Nussbaum's argument that additional doses may have been received from alpha emitters incorporated internally and that these might have been more than is acknowledged by UNSCEAR and the World Health Organization (WHO). Unfortunately the references quoted by Nussbaum as showing that at least 85% of the fuel was released are abstracts that provide no supportive evidence. It is generally accepted that about 3% of the nonvolatile elements present in the reactor were released; while these were mostly deposited close to the reactor, more distant contamination also occurred. We know of no reliable evidence that the majority of the nonvolatile elements were released, and it is accepted that a huge radioactive lava-like mass of fuel remains in the reactor. We are not qualified to comment on the nature of the explosion, but that is hardly an issue if the doses are correctly estimated.

We acknowledge that there have been ecologic studies of increased perinatal morbidity and mortality in areas where doses were low (i.e., of the order of a few millisieverts) (Korblein 2006), but other studies have found no effect (e.g., Dolk et al. 1999; Hausler et al. 1992). The much larger effects that would be expected in populations much closer to the accident, and thus more highly exposed, are not accepted by the WHO and International Atomic Energy Agency (IAEA), and small increases have been attributed to increased recording of minor abnormalities. This does not mean that there has been no effect, and that is one reason why we have called for a comprehensive health assessment of the accident (Williams and Baverstock 2006). These effects were not attributed to the Chernobyl accident by either Fairlie and Sumner (2006) or the Committee Examining Radiation Risks of Internal Emitters (2004).

It is undoubtedly the case that some have sought to downplay the importance of the health consequences of the accident, the WHO and the IAEA among them, but it is also true that others have sought to inflate the health consequences. Fairlie and Sumner (2006) rightly point out the uncertainties involved in reconstructing the accident and thus the need for value judgments in making health assessments. We have doubts about some of the claims made in Nussbaum's letter, but by pointing out the discrepancies between the views of some scientists and the majority, he reinforces one of our main points. The continuing disputes over the consequences of the Chernobyl accident make it essential that a major international organization be created to support authoritative studies of the long-term effects of the world's biggest nuclear accident.

The authors declare they have no competing financial interests.

References

Cardis E, Krewski D, Boniol M, Drozdovitch V, Darby SC, Gilbert ES, et al. 2006. Estimates of the cancer burden in Europe from radioactive fallout from the Chernobyl accident. Int J Cancer 119:1224–1235.

Committee Examining Radiation Risks of Internal Emitters. 2004. Report of the Committee Examining Radiation Risks of Internal Emitters (CERRIE). Available: http://www.cerrie.org/pdfs/cerrie_report_e-book.pdf [accessed 25 February 2007].

Dolk H, Nichols R, EUROCAT Working Group, 1999. Evaluation of the impact of Chernobyl on the prevalence of congenital anomalies in 16 regions of Europe. Int J Epidemiol 28:941–948.

Fairlie I, Sumner D. 2006. The Other Report on Chernobyl (TORCH). Berlin/Brussels/Kiev:Greens/EFA in the European Parliament. Available: http://www.chernobylreport.org/torch.pdf [accessed 25 February 2007].

Haeusler MC, Berghold A, Schoell W, Hofer P, Schaffer M. 1992. The influence of the post-Chernobyl fallout on birth defects and abortion rates in Austria. Am J Obstet Gynecol 167:1025–1031.

Korblein A. 2006. Studies of pregnancy outcome following the Chernobyl accident. In: Chernobyl: 20 Years On (Busby CC, Yablokov A, eds). Documents of the ECRR 2006. No 1. Aberystwyth, UK:Green Audit Press, 227–243. Available: http://www.euradcom.org/publications/chernobylebook.pdf [accessed 12 April 2007].

UNSCEAR. 1988. Annex D: Exposures from the Chernobyl accident. In: Sources and Effects of Ionising Radiation; United Nations Scientific Committee on the Effects of Atomic Radiations. 1988 Report to the General Assembly, with Annexes. New York:United Nations, 309–374. Available: http://www.unscear.org/docs/reports/1988/1988i_unscear.pdf [accessed 6 April 2007].

Williams D, Baverstock K. 2006. Too soon for a final diagnosis. Nature 440:993–994.