The Rural Voice, 1989-07, Page 32Analysis: THE BNPD & LEUKEMIA
What's the risk of getting leukemia if you live near a nuclear power station like
the one in Bruce County? Is there a risk at all? We don't know. Here's why:
by Ian Wylie-Toal
n May 11, people living
within a 25 -km radius of the
Bruce Nuclear Power Development
(BNPD) were confronted by a report
that suggests they could be more like-
ly to get leukemia than the rest of the
population in Ontario. But, the study
added, the increase in the incidence of
leukemia is not significant, and
probably occurred by chance.
The study, "Childhood Leukemia
Around Canadian Nuclear Facilities,"
was commissioned by the Atomic
Energy Control Board (AEBC) after
several British studies in the 1980s ap-
peared to show clusters of childhood
leukemia around nuclear facilities.
The AECB study "examined the
incidence and mortality of leukemia
among children aged 0 - 4 years who
were born to mothers resident in the
vicinity" of nuclear facilities.
Results showed that the "number
of leukemia cases observed ranged
from 0.31 to 3.49 times the expected
values." But because of the small
number of cases identified and statis-
tical uncertainties, "the researchers
point out that these finding may well
be due to chance, as the range falls
within the variations of the natural
occurrence of the disease."
A lower than expected rate of
leukemia was found around nuclear
research centres, and a slightly in-
creased rate around all other types of
nuclear facilities. The highest inci-
dence of leukemia was found around
the BNDP. Four incidents of leuke-
mia were diagnosed between 1964 and
1985 when 1.6 incidents would have
been expected. This is 2.46 times the
normal rate. Two deaths were record-
ed from leukemia between 1950 and
1986 when 0.6 deaths would have
been expected, which is 3.49 times the
normal rate.
The results of this study will no
doubt leave the public, especially
those living around the BNPD, uneasy
"Clusters" of leukemia victims may be
random. Take 400 red and 50 yellow balls
as an example. Shaking them up to
randomly distribute red balls within the
yellow often produces clusters of red balls.
and confused. While the study sug-
gests that the increase was a chance
event, the fact that an increase was
found at all is enough to cause doubt.
We are used to getting scientific
pronouncements regarding our health
that are not definitive one way or
another. How should the public assess
the study of leukemia and the BNDP?
First, it may be helpful to look at the
British studies that prompted the
AECB report.
In 1983, Yorkshire Television
aired a program that revealed a cluster
of four children with leukemia in the
town of Seascale, near the Sellafield
nuclear reprocessing plant. The four
deaths (plus another victim born in the
area who died in another location)
occurred between 1945 and 1980. The
number of deaths from leukemia that
would be expected in that time and
region was 0.5.
After the program was aired, sever-
al studies were undertaken to investi-
gate the findings. Similar studies were
also done at military nuclear sites in
Berkshire and Oxfordshire, at a repro-
cessing plant in Dounreay, Scotland,
and around some nuclear generating
stations. All of these studies say
basically the same thing: that there
are increases to be seen, but the
increases cannot be linked to the
nuclear facilities.
There are several reasons for this.
One is that the amount of radiation
discharged by nuclear plants is too
small to account for the increases in
leukemia. The highest recorded
emission of radioactivity from British
nuclear stations represents only 2 per
cent of natural background radiation.
Using these figures, it has been
estimated that radiation discharges
from Sellafield could account for only
0.1 additional deaths over 35 years.
The British National Radiological
Protection Board released a report in
February of 1988 (New Scientist, 18,
p. 24) that examined all research on
radiation exposure affecting people
living near the Sellafield nuclear
facility, and concluded that radiation
could not be the sole cause of the high
incidence of leukemia around the
station. The authors suggest that
genetic factors, viruses, drugs, and
chemicals may play a part. A 1987
study by the Imperial Cancer Research
Fund Unit in Oxford reached similar
conclusions for the Dounreay cluster.
The fly in the ointment is that the
considered danger of contracting
cancer from radiation has recently
been increased. According to Joseph
Rotblat, emeritus professor of physics
at the University of London, work
done since 1981 has shown that past
assumptions of risk are not correct.
Even taking into account moderating
factors, Rotblat says, "it is difficult to
escape the conclusion that the estimate
of radiation risk is at least five times
greater than the current values of the
ICRP (International Committee for
Radiological Protection)." It is not
clear whether assessments of risk from
power plant emissions were made
using these new criteria.
Another reason why it is difficult
30 THE RURAL VOICE