PTI FEATURE
VOL No XXVIII (32)- 2012 August 11,
2012
ATOMIC ENERGY
PF-
128/2012
Fukushima accident: Research Foundation comes
alive
- By Dr K S Parthasarathy
Looking back to a bit
of history is in order. On 6th August
1945, exactly 67 years ago, an atom bomb destroyed Hiroshima
On March 11, 2011, a rarest of
the rare, powerful earthquake and a
devastating tsunami, led to a serious accident
at the Fukushima Atomic Power Station (Fukushima Daiichi). Many national and international agencies reviewed the accident. The Radiation Effects
Research Foundation at Hiroshima came
alive with several unique programmes
Looking back to a bit of history is in order. On 6th August 1945, exactly 67 years ago, an atom
bomb destroyed Hiroshima. Nagasaki faced devastation three days later. About 90,000- 140,000 people in Hiroshima and
60,000- 80,000 people in Nagasaki died immediately or within two to four months
after bombing, resulting from collapse of houses caused by the blast and from
heat rays and fires and radiation exposure. There was wide spread radiation
exposure to the surviving population. Gruesome consequences of high radiation
exposures were clearly visible.
On November 18, 1946 the US President, Harry Truman authorized the
National Research Council to establish an agency "to undertake a long
range, continuing study of the biological and medical effects of the atomic
bomb on man". This organization grew into the Atomic Bomb
Casualty Commission (ABCC). ABCC which rose from nuclear ashes, continued its
research and development programmes till
1975 when Radiation Effects Research Foundation (RERF) was set up as
a US-Japan bi-national endeavour.
The
RERF carried out "laboratory-based
research studies in the fields of radiobiology, immunology, genetics, and
molecular epidemiology are carried out to help interpret the various findings
and contribute to the understanding of the mechanisms of disease induction".
The
Foundation established many fixed
cohorts or sub-cohorts to provide epidemiological and clinical data on the
health status and mortality of the survivors and their children. RERF researchers developed expertise in radiation
dosimetry, radiation biology and epidemiology among others. The agency is a
truly a research and development organization of professionals with no
commitment to promote nuclear industry or radiation technology.
RERF
has thus been in the forefront of
various radiation studies for over six decades. More than any other agency,
RERF is equipped to offer guidance on radiation
related matters including radiation exposures to populations
Since March 11, 2011, RERF staff had a very busy period. RERF was
flooded with general public inquiries and media requests
for information. During the first three days (including Saturday and Sunday) after the initial disaster, RERF received
more than 50 telephone inquiries
regarding a wide variety of issues, not just about fields of research pursued by RERF. Based on such inquiries, RERF
staff prepared a list of the most frequently asked questions on March 14 and distributed it to all staff
The most important contribution of RERF staff during the Fukushima crisis was the creation
of a special webpage . On March 15, 2011, on its website’s “What’s New” page,
RERF notified the general public of availability
of brochures dealing radiation health effects. On March 17, a special webpage provided questions and answers regarding radiation
health effects, some relevant brochures,
a listing of institutes related to health care for the radiation-exposed in
Japan, and other related information
from both Japan and abroad. An English version of the webpage was made available on March 18, and thereafter,
the webpage has been updated when necessary.
RERF described in one page matters
elucidated thus far by its studies.
RERF's epidemiological research of A-bomb survivors
has revealed long-term health effects
from radiation. According to RERF, a radiation exposure of 1 sievert (1,000
millisieverts -mSv-, or 1,000,000 microsieverts)
at age 30 increases risk of dying from solid cancer (cancer as generally
understood, excluding leukemia) at age
70 on an average of about 1.5 times for
both sexes.
The risk increases in direct
proportion to radiation dose above
around 100 to 200 mSv. RERF clarified
that the association remains unclear below that level. (Sievert
is a unit of biologically significant radiation dose; since it a large quantity , millisievert (one
thousandth) or microsievert (one millionth) is commonly used. The skin dose in
a chest x-ray examination may be as high as one millisievert)
"If we assume that cancer
risk is proportional to radiation dose
without “threshold” (the demarcation point above which there are effects and below which there are
no effects), it is projected that exposure to 100 mSv and 10 mSv increases
cancer risk by about 1.05 and 1.005 times, respectively." RERF noted
Lifetime risk of radiation-associated cancer mortality can also be
estimated on the basis of such data. Exposure to about 100 mSv at age 30 is
thought to increase lifetime risk of cancer mortality, which is 20% without
radiation exposure, to about 21 % (increase of 1 percentage point) on average
for both sexes.
RERF described the difference
between A-bomb exposure and exposure to
environmental contamination: A-bomb exposure was a single, acute exposure, while
environmental contamination causes chronic exposure; scientists believe that the effects of chronic exposure is smaller than those from
acute exposure. Based on this theory, chronic exposure to a total dose of
about 100 mSv would increase lifetime risk by 0.5 to 0.7 percentage point.
Another finding of RERF is that among people exposed to high dose
radiation (at least 1 sievert), increased frequency of non-cancer diseases
(cataract, benign thyroid tumor, heart disease, etc.) has been observed.
RERF studies have not found thus far any inherited
genetic effects from parental radiation exposure among the children of A-bomb survivors. This is contrary
to public perception.
The web page contained a brochure
titled "Basic Guide to Radiation and Health Sciences". It describes
the historical developments followed by basic principles of radiation
protection, use of radiation in medicine, biological effects of radiation and
brief details of epidemiological research.
RERF "conducts medical research and studies for peaceful purposes,
with a view to protecting the world's people from radiation effects. RERF hopes
that its efforts can prove useful in the attainment of health and wellbeing for
not only for those exposed to the A-bombs but for all people throughout the
world." -- PTI
Feature
Dr K S Parthasarathy is former Sectretary, Atomic Energy Regulatory Board
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