NEWS AND VIEWS: Conference on genetics examines implications of Chonobyl's aftermath (11/10/96)

NEWS AND VIEWS

Conference on genetics examines implications of Chonobyl's aftermath

by George W. Widney

RIO DE JANIERO, Brazil - Coincidentally, but significantly, on the fifth anniversary of the independence of Ukraine, the workshop "Chornobyl: Implications of a Decade" took place in conjunction with the ninth International Congress of Human Genetics held in Rio de Janeiro, Brazil.

The conference was organized by Dr. Wladimir Wertelecki, coordinator of the American-Ukrainian Medical Sciences Group. A co-sponsor was Dr. C. Salinas, president of the Ibero-American Society of Human Genetics of North America. The conference was sponsored by the National Institute of Health (Child-Human Development and Environmental Health Sciences), as well as by individual donations of many generous Ukrainian Americans augmented by funds of the University of South Alabama and the Medical University of South Carolina.

During the introductory remarks, Dr. Wertelecki (University of South Alabama, Mobile, Ala.) underscored that many experts consider that the legacy of Chornobyl played a significant role in the public spirit which led to the collapse of the USSR. He also emphasized that Chornobyl, contrary to other nuclear accidents, represents a chronic and ongoing challenge on an unprecedented scale. Ionizing radiation is one of the best known causes of genetic mutations, which result in birth defects as well as cancer.

The gathered experts were of the opinion that Chornobyl continues to raise more questions than are being answered. Concerning human genetics and teratology (environmentally induced birth defects), it is evident that such issues have not received major emphasis thus far, despite public concerns over a precipitous drop of birth rates in Belarus and Ukraine.

lt is also evident that the role played by independent investigators, in contrast to experts engaged by "bureaucratized agencies," has been quite modest. The credibility that independent, non-governmental investigators can contribute to increase public confidence in scientific investigations needs greater attention. In the past, reports by various "atomic" agencies have not gained public credibility.

Among the key presentations was a review by Dr. L. Anspaugh (National Livermore Laboratory, Livermore, Calif.), who spoke as an expert in radiobiology and on behalf of his colleagues in Belarus, Ukraine and Russia. Dr. Anspaugh pointed out that radioactive deposition patterns impacted most significantly the territories of Belarus, Ukraine and Russia. In 1988, predictions were made that there might be something on the order of 17,000 cancer cases that would occur as a consequence of the accident. However, it was also pointed out that most of the total dose was actually delivered outside of the former Soviet Union and scattered across the world, which makes the detection of such cancer cases quite difficult.

Dr. Anspaugh also indicated that substantial efforts were made to measure directly the radioactive contents detected in milk and people. He stated that there is a large body of data obtained from direct measurements of the Ukrainian population. During the 10 years since the accident, 65 percent of internal radiation is from cesium that has been ingested with food. Significantly, 80 percent of this dose has accrued to the rural population, where controls or the source of food are quite different than those of the urban populations. The genetically significant dose is estimated at 50,000 persons/Seivert in the contaminated area, and beyond the contaminated area the estimate is about 300,000 persons/Seivert.

Concerning thyroid cancer, Dr. Anspaugh pointed out that there are more than 1,000 patients and because this number is so much larger than expected there is no doubt that it is due to radiation originating from Chornobyl. Put in another way, there are now more childhood thyroid cancers in the affected countries than all cancers induced by the atomic bombs that fell on Japan.

The magnitude of the increase in thyroid cancer was not expected, he said. The onset so soon after the Chornobyl accident also was not expected. There is something profoundly different about the Chornobyl experience because the increase is so large and so soon. "Something is going on that is not completely understood," he said. Another surprising thing is that the doses for the cases are actually quite low. How many more cases of thyroid cancer will emerge is hard to say.

Subsequent speakers discussed the importance of chromosome studies and how the emerging findings may help researchers understand the process of the origin of cancers. Participants from Belarus (Dr. G. Laziuk) and Ukraine (Dr. I. Baryliak) presented data about birth defects and stressed the importance of establishing a birth defects surveillance system using the procedures developed by an international consortium coordinated from Rome. The dramatic and worrisome drop of the birth rates in Ukraine and Belarus were discussed by Dr. L. Tegako (Belarus), who also presented an outline of approaches to assess human biosocial adoption.

In a paper submitted by Dr. J. Neel (University of Michigan Medical School, Ann Arbor, Mich.), a world- renowned radiation geneticist who pioneered many studies of the Hiroshima/Nagasaki bomb survivors and their children, it was pointed out that "if we had to do such studies over again, the most obvious change in the research design would be to include studies at the DNA level from the outset." Dr. Neel also suggested including the following components of Japanese studies in prospective studies concerning the genetic effects from Chornobyl: frequency of congenital malformations and still-births; death rates among live-born children; growth and development of surviving children, cancer and chromosomal abnormalities in children of exposed parents.

George W. Widney is a science reporter.