Problems complicating a full assessment of the effects from Chernobyl included official secrecy and falsification of medical records by the USSR for the first 3.5 years after the catastrophe and the lack of reliable medical statistics in Ukraine, Belarus, and Russia. Official data concerning the thousands of cleanup workers (Chernobyl liquidators) who worked to control the emissions are especially difficult to reconstruct. Using criteria demanded by the International Atomic Energy Agency (IAEA), the World Health Organization (WHO), and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) resulted in marked underestimates of the number of fatalities and the extent and degree of sickness among those exposed to radioactive fallout from Chernobyl. Data on exposures were absent or grossly inadequate, while mounting indications of adverse effects became more and more apparent. Using objective information collected by scientists in the affected areas—comparisons of morbidity and mortality in territories characterized by identical physiography, demography, and economy, which differed only in the levels and spectra of radioactive contamination—revealed significant abnormalities associated with irradiation, unrelated to age or sex (e.g., stable chromosomal aberrations), as well as other genetic and nongenetic pathologies.
In all cases when comparing the territories heavily contaminated by Chernobyl's radionuclides with less contaminated areas that are characterized by a similar economy, demography, and environment, there is a marked increase in general morbidity in the former. Increased numbers of sick and weak newborns were found in the heavily contaminated territories in Belarus, Ukraine, and European Russia.
Accelerated aging is one of the well-known consequences of exposure to ionizing radiation. This phenomenon is apparent to a greater or lesser degree in all of the populations contaminated by the Chernobyl radionuclides.
This section describes the spectrum and the scale of the nonmalignant diseases that have been found among exposed populations. Adverse effects as a result of Chernobyl irradiation have been found in every group that has been studied. Brain damage has been found in individuals directly exposed—liquidators and those living in the contaminated territories, as well as in their offspring. Premature cataracts; tooth and mouth abnormalities; and blood, lymphatic, heart, lung, gastrointestinal, urologic, bone, and skin diseases afflict and impair people, young and old alike. Endocrine dysfunction, particularly thyroid disease, is far more common than might be expected, with some 1,000 cases of thyroid dysfunction for every case of thyroid cancer, a marked increase after the catastrophe. There are genetic damage and birth defects especially in children of liquidators and in children born in areas with high levels of radioisotope contamination. Immunological abnormalities and increases in viral, bacterial, and parasitic diseases are rife among individuals in the heavily contaminated areas. For more than 20 years, overall morbidity has remained high in those exposed to the irradiation released by Chernobyl. One cannot give credence to the explanation that these numbers are due solely to socioeconomic factors. The negative health consequences of the catastrophe are amply documented in this chapter and concern millions of people.
The most recent forecast by international agencies predicted there would be between 9,000 and 28,000 fatal cancers between 1986 and 2056, obviously underestimating the risk factors and the collective doses. On the basis of I-131 and Cs-137 radioisotope doses to which populations were exposed and a comparison of cancer mortality in the heavily and the less contaminated territories and pre- and post-Chernobyl cancer levels, a more realistic figure is 212,000 to 245,000 deaths in Europe and 19,000 in the rest of the world. High levels of Te-132, Ru-103, Ru-106, and Cs-134 persisted months after the Chernobyl catastrophe and the continuing radiation from Cs-137, Sr-90, Pu, and Am will generate new neoplasms for hundreds of years.
A detailed study reveals that 3.8–4.0% of all deaths in the contaminated territories of Ukraine and Russia from 1990 to 2004 were caused by the Chernobyl catastrophe. The lack of evidence of increased mortality in other affected countries is not proof of the absence of effects from the radioactive fallout. Since 1990, mortality among liquidators has exceeded the mortality rate in corresponding population groups. From 112,000 to 125,000 liquidators died before 2005—that is, some 15% of the 830,000 members of the Chernobyl cleanup teams. The calculations suggest that the Chernobyl catastrophe has already killed several hundred thousand human beings in a population of several hundred million that was unfortunate enough to live in territories affected by the fallout. The number of Chernobyl victims will continue to grow over many future generations.