Health Risks of Ionizing Radiation: - Clark University

Figure 12-3. Native Americans from San Ildefonso Pueblo
and Los Alamos residents (http://www.lanl.gov/history/
communities/index.shtml).
when radiation leaves the site of a facility. These
studies frequently use as an endpoint the group of
cancers including leuekemia and non-Hodgkin’s
lymphoma; we refer to this group below as LNHL.
Sellafield. Epidemiological studies of childhood
cancer near nuclear facilities in the UK began in
1983 when a television program suggested that
there was a cluster of childhood leukemia in the
village of Seascale, a couple of miles from the
Sellafield reprocessing facility in England (Gardner
et al. 1991). An independent government inquiry
established that the excess, although based on a
small number of cases, did appear to exist (Black
1984, Gardner 1991). Draper et al. (1993) conducted
a similar analysis through 1990 that confirmed the
excess of childhood LNHL in Seascale 1963-1983
and showed a continuing excess for 1984-1990
in addition to a possible excess of other cancers 8 .
There was no evidence of an increase in areas
immediately surrounding Seascale and Sellafield.
In the 1995 the National Radiological Protection
Board published a dose reconstruction and risk
assessment for 1348 children born in Seascale
between 1945 and 1992 (Simmonds et al. 1995).
The expected number of radiation-induced LNHL
cases in the cohort was 0.46, and Sellafield releases
were estimated to contribute only 10% of this risk
(the rest being natural radiation); unfortunately no
Communities Near Nuclear Facilities 149
uncertainty information was provided. Predictions
of radionuclides in the bodies of Seascale residents
were consistent with several sets of measurements
suggesting that the dose estimates were reasonable
(Simmonds et al. 1995).
The rate of stillbirth around Sellafield was
also evaluated. Wakeford and McElvenny (1994)
reported that the stillbirth rate within 25 km of
Sellafield was normal (these authors were at the
time working for British Nuclear Fuels, the public
liability corporation running Sellafield). Dummer et
al. (1998), controlling for year of birth, social class
and birth order, also found a normal stillbirth rate in
this area generally. Stillbirths were further analyzed
by distance from Sellafield (Dummer et al. 1998).
This kind of analysis is problematic because the
deposition of airborne pollutants does not always
correspond to distance from a facility. A high
smokestack, for example, might cause pollutants
to pass above houses close to a facility and wind
direction might cause pollutants to be deposited in
a spatially nonuniform way. The authors considered
5 km rings around Sellafield out to 25 km and
found no stillbirth trend with distance. They did,
however, find significantly increased stillbirth rates
10-15 km north of Sellafield in 1950-1959 and 15-
20 km northeast of Sellafield in 1980-1989 and also
determined that there was a significant excess in
the north-northeast direction at all distances 9 . Some
Sellafield discharges to the sea have blown ashore
over the years and Dummer et al. (1999) evaluated
stillbirths a second time according to distance from
the coast in 2.5-km rings; no trend with distance was
found.
Dounreay. The Dounreay nuclear reprocessing
plant in Caithness, Scotland was the subject of a public
inquiry in 1986 that was followed by several studies.
It became apparent that there was a leukemia cluster
near the facility but researchers have been unable
to find a cause or to rule out any possible causes. In
the first study of Dounreay, Heasman et al. (1986)
reported excess cases of childhood leukemia within
12.5 kilometers of the facility from 1979 to 1984;
8 For ages 0-24 there were 5 cases of LNHL in 1963-83 (0.49 expected) and 2 cases in 1984-90 (0.12 expected). In
1984-1990 there were two cases of ‘other’ cancers; there was only an 8.3% chance of these two cases occurring
based on national rates.
9 The Odds Ratio for one northeast direction category was 1.12 (1.00-1.24) and for an adjacent north-northeast category
was 1.07 (0.96-1.19). Many of the stillbirths in these directions occurred more than 25 km from Sellafield.