Environmental Engineering Reference
In-Depth Information
The man sievert (man-Sv): If you add all the individual effective dose equivalents
of a group of people, you have what is known as the collective effective dose equivalent ,
which is measured in man-Sv.
Finally, if you are still with me, many radionuclides have half-lives measured in thou-
sands of years. Therefore, we have the concept of collective effective dose equivalent com-
mitment , which is the collective effective dose equivalent that will be delivered to many
generations of people.
In the rest of this chapter, we will frequently hear about the effective dose of radiation
resulting from a particular source and the reader will probably be wondering what the
health implications of such a dose may be. In fact, this is a very complicated question with
no simple answer. However, I hope the following will help. To investigate the long-term
effects of radiation, scientists speak about stochastic effects. These are radiation-induced
health effects that occur without a threshold level of dose. The probability of the expec-
ted effect is proportional to the dose, but the severity is not. Radiation-induced cancers
and hereditary effects are examples of stochastic radiation effects. They characteristically
have a late appearance measured in years (for cancer) or in generations (for hereditary ef-
fects). Using this approach, the International Atomic Energy Agency (IAEA) conducted a
life span study on survivors from Hiroshima and Nagasaki and calculated a fatal solid can-
cer mortality risk of 0.005% per mSv.
There will be no more new units of measurement to remember in this section!
Search WWH ::




Custom Search