Radioactivity - The Changing Arctic Environment: The Arctic Messenger - page 70

Natural Radioactivity and TENORM

According to the United Nations Scientific Committee on the Effects of Atomic Radiation
(UNSCEAR) in 2000, the annual worldwide per caput effective dose of radiation from nat-
ural and man-made sources could be summarized as follows:

· Natural background: 2.4 mSv, with a typical range of 1 to 10 mSv but with some

large populations exposed to 10 to 20 mSv

· Diagnostic medical procedures: 0.4 mSv, with a range of 0.04 to 1.0 mSv depend-

ing on level of health care

· Atmospheric nuclear testing: 0.005 mSv decreased in the Northern Hemisphere

from 0.15 mSv in 1963. Levels are higher at high northern latitudes, where they
vary considerably with diet.

· Chernobyl accident: 0.002 mSv in the Northern Hemisphere decreased from 0.04 in

1986

· Nuclear power production: 0.0002 mSv

You will notice that the large variation in these figures relates to diagnostic medical sources.
The effective dose is much higher incountries with developed economies. Consequently,the
U.S. National Research Council reports that the average effective dose in the United States
is approximately 50% natural and 50% man-made, with the latter being made up of the sum
of diagnostic radiological imaging and the use of radiation to treat disease (totalling 48%)
and consumer products (2%).
For many people, it comes as a surprise to learn that most of us receive such a high pro-
portion of our lifetime dose of radiation from natural sources, especially from radon gas that
enters our increasingly sealed homes and workplaces. We will take a brief look at this fact
because it helps put the anthropogenic sources into perspective. This is particularly useful