CHERNOBYL INFANT LEUKAEMIA PUTS FIGURE ON RISK ERROR

Report from Radioactive Times Volume 4, Number 1, June 2000 (content not updated)

Strontium Wombles Proved Right

In June, the peer-review journal Energy and Environment carried a report of a study of infant leukemia in Wales and Scotland in those children who were exposed to the fallout. ^[1]

After the Chernobyl accident in April 1986, rainfall precipitation caused measurable contamination of Wales and Scotland. Figures for exposure were published by the National Radiological protection Board. Chris Busby and Molly Scott Cato approached the Scottish and Welsh cancer registries and obtained figures of infant leukemia cases for the period of the main contamination and also for a substantial period either side of 1986. Thus everything was in place to examine the predictions of the current risk model for radiogenic leukemia. NRPB doses could be multipled by the population at risk and then by the ICRP risk factors to give the number of cases of leukemia in those most affected by the fallout, the unborn children in the womb. The number predicted was much less than one case in the combined population.

This group, or cohort is a very specific one. If there were a significant increase in leukemia in this group then there is only one conclusion: the cause is exposure to radiation.

Huge Risk Error

Using the ten years before the Chernobyl accident as a ‘control’ group, the researchers found that the average annual number of cases of infant (age 0-1) leukemia in the combined population of Wales and Scotland was about 3 cases. In the period January 1987 to June 1988 there were 12 cases, giving a Relative Risk of 3.87 (p = .0001). For the Wales infants the figure was 4.4 (p = 0.004)

Dividing the excess cases found by the number predicted by the NRPB risk model calculation shows an error of 100-fold or more. This size of error is able to explain the anomalous childhood leukemia clusters near the various nuclear sites.

Germany, Greece and USA

It is not as if this is an isolated observation. Infant leukemia increases were reported in the last ten years from three other countries where researchers have looked, namely Germany ^[2], Greece ^[3] and the U.S.A ^[4]. The advantage of the UK data is that the doses were quantified by NRPB and therefore some figure could be put on the level of risk factor error. This is the first time that such an attempt has been made for this kind of exposure to man-made radioactive isotopic exposure. The table below shows that significant infant leukemia was induced by the Chernobyl fallout in four countries. The exposed cohort here are those children born between 1st July 1886 and 31st Dec 1987. The unexposed cohorts A and C are those born between Jan 1st 1980 and 31st Dec 1985 plus those born between Jan 1st 1988 and Dec 31st 1990.

Biphasic response

Joe Mangano in the United States, where the fallout exposure was very low, found a weak effect with Relative Risk 1.3. A close look at the effect in England, where there was very little fallout also shows a weak effect. All of these responses plotted together show the familiar biphasic up-down-up Burlakova type response which has been discussed in earlier editions of Radioactive Times.

Copies of the full paper are available on request from LLRC.