Slide 4 – Ionized Radiation
•Affect of this radiation is obvious. All scientists agree that this radiation is
really harmful. How does it affect human health? First, the radioactive material
(like Uranium), decays naturally and spontaneously, and produces ionizing
radiation. This ion radiation, strips away electrons from atoms (create two charged
•It can also break some chemical bonds. This is important for human body as
it consists of water and chemicals. Examples: alpha, beta particles, gamma and x-
rays. These examples differ based on the amounts of energy they have.
Slide 5 - Health effects from exposure to radionuclides
There are 2 different kinds of health effects.
1) Stochastic effect – Humans exposed to long term, lower level of radiation. This is most
problematic because it is very hard to detect and to know what will happen to our health
after long time exposure to lower level of radiation. Hard to detect and not 100% known.
What is known is that if the amount of radiation increases the severity of this affect will
not change and will stay the same and the type of illnesses will be the same. But the risk
to get that illness will increase. Risk of getting cancer will be higher. This amount of
radiation is proven to cause cancer. 2 effects associated with this Stochastic:
Cancer is uncontrolled growth of cells (any kinds of cells as there are many kinds of
cancers). Naturally in our physiological functions, our cells divide and produce new ones
to replace old ones. This natural physiological process is controlled by our genetic
material. But if certain radiation disrupts this natural process, it will cause cancer.
Basically, cells keep on growing without reason. And this reason is radio nuclides.
Another effect that can be caused is changes in DNA (changes to genetic material).
Two problems can happen because of this. One is Teratogenic changes and another is
genetic changes (mutations). What are teratogenic effects: birth defects. Mother is
exposed for long term to lower level of radiation (most sensitive in 8- 15 week of
pregnancy) ; her unborn child will have some problems like smaller head or brain size,
poorly formed eyes, mental retardation. Genetic mutations are changes that can be
transferred from the parent to the child. Teratogenic changes cannot be transferred to the
child, but the offspring is affected anyways, which we see when child is born.
2) Non-Stochastic effect – These are acute effects. These effects are seen in humans that
are exposed to very high levels of radiation for a short period of time. These effects are
also very visible and obvious. These effects, if level of radiation increases, will get more
severe. We know this based on cases of many different nuclear accidents everywhere
(Chernobyl, Hiroshima Nagasaki, workers that are exposed to very high level of radiation
Some literature says that these effects can cause cancer, but some literature disagrees
that it causes cancer. Based on Epidemiological studies and other examples, it seems that