BIER Report VII: Biologic Effects of Ionizing
Radiation (BEIR) develops the most up-to-date and comprehensive risk estimates
for cancer due to exposure to radiation.
The report which gives
results of the life time cancer risk calculation using mathematical models from
an exposure of 100 mSv dose to a typical US population. The calculations
predicted one individual in 100 persons would be expected to develop solid
cancer or leukemia. This can be compared with the expected 42 cancer cases that
would be developed in 100 persons spontaneously due to other causes!
Risk is lower at lower
exposures. Similar calculations for a lower dose of 10 mSv predict one out of
1000 exposed individual would develop cancer. However, it is very difficult due
to statistical limitations, to predict reliable number of cancers at these low
levels of exposure. Now, 100 mSv is the occupational dose limit for radiation
workers for 5-year period, average of 20 mSv per year. The world average
natural background radiation is 2.4 mSv in a year to which all of us are
exposed. Average radiation exposure of the occupational workers, in general, is
in the range of natural background radiation levels.
Under such situations of
uncertainty how one can assume that at low doses, the cancer risk is linearly
lower? It is quite possible that the
risks are lower than predicted by LNT model or non-existent or even beneficial
to health. There is also no direct evidence of increased risk of non-cancer
diseases at low doses.
Now why at all assume
existence of cancer risk at such low levels of radiation and impede progress of
the nuclear industry worth billions of dollars?
[The BIER VII document: Health Risks from
Exposure to Low Levels of Ionizing Radiation is available from the National
Academies Press, 500 Fifth Street, NW, Washington, DC 20001, 2006]
