Will Chernobyl Legacy Be Deadlier? : What Soviets Understated or Ignored Is Cause for Alarm
In the middle of this century it became obvious that the accumulation of radioactive products in the biosphere was affecting all of humanity. Because of above-ground tests of nuclear weapons, a lot of isotopes accumulated and the background of radioactivity was increasing all the time. At the same time, the number of people suffering from cancer and hereditary diseases was rising. All this became a powerful factor in stimulating public protests that led to the conclusion of a treaty in 1963 between the Soviet Union and the United States banning above-ground tests. After this the radioactive background stabilized to a considerable degree.
As a result of the Chernobyl catastrophe, no fewer than 100 million curies of radioactive isotopes were discharged into the atmosphere. In other words, background radiation doubled at once. One must expect many more undesirable biological consequences than are now assumed.
First and foremost, the question is on the growth of cancer cases and the deaths caused by cancer. This question was discussed in the Soviet report to the International Atomic Energy Agency, and the estimates given at that time satisfied many Western specialists. In the British journal Nature, the reviewers noted that the growth of cancer was not going to be as strong as was first feared.
To comprehend the meaning and direction of the conclusions in the report, we would have to pay attention to an issue that perhaps may appear to be too specific. But without examining this issue we would not be able to look into one alarming circumstance that was concealed in the Soviet report. This issue concerns quality composition of the isotopes discharged into the atmosphere as a result of the accident.
Among those isotopes were those with a relatively brief half-life, from seconds to a few days. But there were also isotopes with a long period of life, equal to dozens of years or more. Immediately after the accident, the Soviet mass media talked mainly about the radioactive isotope of iodine 131. Its half-life is relatively small--about eight days. It was reported that 50% to 80% of all radiation that fell to the ground was made up of this particular isotope. In connection with this, it seems logical that the main efforts of all investigators involved in the analysis of the Chernobyl catastrophe (more than 7,000 scientific groups) were directed to measurements of the levels of iodine 131 in human thyroid glands.
I was a little surprised by this circumstance, because I consider that no less important was the study of the effect of long-lived isotopes, especially those like caseium 137, with a half-life of 33 years, and strontium 90, with a half-life of 27.7 years. I was also surprised by the fact that in most of the tables provided in reports, the columns with percentage contents of isotopes in the air, soil, water of rivers and lakes and in vegetables and meat products were absent. Where the information permitted, I had to recalculate the figures provided to clarify what percentage of total radiation was accounted for by different isotopes.
This analysis showed that the initial reports about the primary role of iodine were wrong. In reality, iodine 131 formed no more than 10% to 15% in the majority of the tests. The long-lived isotopes often formed more than one-third of the total amount of radioactive substances.
Yet the estimate of the future increase in cancer deaths was based on the presence of iodine 131 in the radioactive dust that fell on that part of the Soviet Union where 75 million people live. This estimate was most reliably determined, and was discussed in the report with assurance. It showed an increase of “less than 0.05% from the level of death rates caused by spontaneous cancer (about 9.5 million cases over 70 years) among a given population.”
However, the same report mentioned--although only in passing--the fact that the influence of the long-lived isotope caseium 137 on the number of cancer deaths would be almost 10 times greater because the number of deaths caused by it would add “0.4% from the natural death rate caused by malignant neoplasms.” These words are supplemented by a paragraph about one more long-lived isotope, strontium 90. The report said that there was insufficient information at that time to make correct estimates of the death rate associated with that isotope, although the authors of the report admitted that “with time, perhaps, this nucleon would have, along with caseium 137, the most important meaning.”
Thus the figure of 0.05% that dazed many specialists in reality was related only to the consequences of the external gamma irradiation. The main harm would come from the radioactive isotopes of caseium, strontium, serium and other long-lived isotopes, including the isotopes with alpha disassociation. So one should not take this figure 0.05% as the final truth. When it was obtained, too many unjustified assumptions were made, and the precision of the measurements was low.
Perhaps all these circumstances led to the fact that even those who are favorably disposed to the Soviet Union did not agree with such an estimate. The American specialist on the transplantation of bone marrow, Dr. Robert Gale, said last October on Soviet television that the frequency of cancer deaths could be 1% greater (about 6,000 additional) than usual.
One does not want to believe that the American scientist would turn out to be right. For everyone, it would be better if the figures given in the Soviet report would turn out to be too high. But there is no basis for such a view.
The amazing peculiarity of the Soviet report is that there were no references, not to mention quantity estimates, concerning the future increase of hereditary disorders.
Specialists in genetics know that the frequency of hereditary diseases is greater than the frequency of cancerous degeneration under the influence of the same doses. This correlation applies to the consequences of Chernobyl as well. Thus, in particular, West German scientist Helmut Girsch recently said that “in the Federal Republic of Germany it is expected there will be from 4,000 to 23,000 additional cases of cancer (not counting the cases of cancer of the thyroid gland) and 90,000 hereditary disorders.”
These hereditary disorders would affect directly not only those who were subject to irradiation--the breakage of genes would be inherited in many cases by the descendants. Thus the growth of the number of hereditary diseases, deformities or abnormalities of development, spontaneous abortions and premature births will turn out to be a more sinister result of Chernobyl than cancer diseases and cancer deaths. Multiplied in generations, the genetic burden of Chernobyl would be even heavier for humanity.
It is necessary to point out one more detail. In the human environment, too much chemical contamination is accumulated, which affects genes in an inauspicious way. In experiments carried out in many laboratories in the world, including my former laboratory in Moscow, an important rule was ascertained: Under the simultaneous effect of both radiation and chemical mutagents, most often there is an explosion of mutations rather than a simple addition of separate effects.
In a whole series of my experiments on bacteria and plants, the output of mutations exceeded by 10 times the ordinary sum. Since nearly one-third of the radioactive substances expelled by the Chernobyl reactor were made up of isotopes with a long life, and since in the environment the harmful chemical substances--products of the chemical industry--are always accumulating, one could expect that the consequences of Chernobyl would turn out to be more serious than is now anticipated.
