Top-Quality Statistics Show Radiation Damage in Berlin Due to Chernobyl Incident

(Original title: Hochkaraetige Studie belegt Strahlenschaeden in Berlin durch Tschemobyl-Unfall. Merkurstab 1994; 47: 631-3. English by A. R Meuss, FIL, MTA.) 

Even small quantities of ionizing rays evidently increase the risk of teratogenesis. As has now been shown, the assumption that the atomic reactor incident at Chernobyl would have no consequences for pregnant women and unborn children was mistaken. Nine months after the catastrophe the number of children with Down syndrome born in Germany - and especially in Berlin, an area where particularly careful records have been kept - exceeded the averages recorded for many years. A report published in the British Medical Journal (vol. 309,17 July 1994) confirms that as far as pregnancy risks are concerned there is no lower limit of exposure to radioactivity, something which has been suspected for some years.

Karl Sperling, head of the Institute of Human Genetics at the Independent University in Berlin, published the first results of a survey in April 1987. According to this, there had been an increased incidence of trisomy 21. Prenatal diagnostic screening will show if a fetus has the extra chromosome 21, which is the cause of Down syndrome (formerly called "mongolism") with its range of physical and mental abnormalities. Until now, no single external factors had been identified as causing trisomy 21. High radiation doses had been suspected for some time, but exposure to low doses was thought to be of no real concern.

Dr. Sperling now presents a careful analysis of all data from 1980 to 1989. West Berlin had been a political "island" so that it had been possible to register all cases and analyze the 13,000 prenatally diagnosed instances (among 190,000 live births). The 10-year period of observation now permits valid conclusions.

The monthly average was 2 or 3 trisomies 21. In January 1987 there were 12 cases. According to Sperling, this "statistically highly significant" increase can only be due to Chernobyl radiation. No other environmental causes or differences in parents' ages for instance were established. The main radiation exposure in Berlin was between 29 April and 8 May 1986. This was also the time when the twelve women with trisomy 21 children conceived. Abnormalities during first and second meiosis (maturation division of embryonic cells) caused the presence of the extra chromosome; these meioses occurred during the period of maximum radiation exposure.

When the first data causing serious concern were presented in April 1987, disagreement existed between the definite biological data (increased incidence of trisomy 21) and radiation measurements (relatively low exposure). But according to Sperling, we now have a "very plausible explanatory hypothesis." The probable cause of the chromosomal changes was not the long-lived cesium 137, which was mainly detected, but iodine 131, which has a short half-life. "Radiant" iodine 131 is especially well absorbed by the thyroid, particularly in regions such as Germany where iodine levels are low.

Action of Iodine
The fact that increased incidence of trisomy 21 was statistically demonstrable in Berlin may also be due to exposure to different isotopes. The "Chernobyl cloud" that mainly brought high radiation levels to southern Germany may have contained a much higher proportion of short-lived iodine 131 in the northeast [Berlin area]. Added to this is the fact that trisomy 21 records have nowhere been as complete as in Berlin.

When Sperling published the Berlin figures in April 1987 and shortly afterwards the findings of 40 Federal German laboratories, the authorities raised enormous objections. Approx. 30,000 chromosome studies had shown a slight increase in trisomy 21. At me time 15 of the 17cases suspected of being connected with Chernobyl had been reported in southern Germany. The Federal Government's Radiation Protection Commission declared in a publication of the Federal Department of me Environment (Auswirkungen des Reak- torunfalls in Tschemobyl auf die Bundesrepublik Deutschland - Veroeffentlichungen der Strahlenschutzkommission Band 7, Gustav Fischer Verlag) that no connection existed between congenital malformations and low radiation doses. The Commission referred to data relating to the atom bombs dropped on Hiroshima and Nagasaki (now out of date) and animal experiments, literally stating "that malformations are only caused, even during the sensitive stages (of pregnancy), if threshold doses are exceeded." Radiation exposure in the Federal Republic after the catastrophe in the Ukraine had, according to them, been "considerably below those threshold levels. An increased incidence of malformations and developmental abnormalities due to radiation was not to be expected." If it happened at all, such an increase would be in a range that for methodological reasons could not be statistically analyzed.

As late as September 1992 the Federal Department of Radiation Protection (Neuherberg/Munich) published the figures for a long-term study of "pregnancies and births following the Chernobyl reactor incident." Again, any connection was denied, though the Neuherberg Institute of Radiation Hygiene refers mainly to premature births. According to them, "no difference" could be found between Federal German areas exposed to higher and lower radiation doses.

As recent reports in the Sueddeutsche Zeitung (30 June 1994) stated, the incidence of thyroid and hemopoietic system (leukemia) cancers in children and of other types of cancer also in adults had also shown a much more drastic rise (albeit closer to the site of the Chernobyl incident) than even the more pessimistic estimates anticipated. Scientists state that mal- formations and cancer due to ionizing radiation are largely based on the same mechanisms.

Sperling now emphasizes in the British Medical Journal that the period of conception involves particularly high risks for women, even if radiation doses are low. Any exposure of this kind, including diagnostic X-rays, should be avoided as far as possible. What is more, the results suggest that this kind of exposure is an indication for genetic counseling and possibly also prenatal investigations.

Dr. Sperling is asking for further investigations of low radiation dose effects. An application to do an investigation for the whole Federal area has been lodged with the Federal Department of Health for some time, but there has been no reply so far.

Justin Westhoff

Reference

- Based on Sueddeutsche Zeitung No. 172,28 July 1994.