Manmade sources - hdbk11300070

DOE-HDBK-1130-98

Module 2 Biological Effects

Instructor's Notes

1) Some of the contributors to terrestrial sources are the

natural radioactive elements radium, uranium, and

thorium.

2) Many areas have elevated levels of terrestrial radiation

due to increased concentrations of uranium or thorium in

the soil.

c. Internal (total average dose ~40 mrem/yr)

1) The food we eat and the water we drink contain trace

amounts of natural radioactive materials.

2) These naturally occurring radioactive materials deposit

in our bodies and cause internal exposure to radiation.

3) Some naturally occurring radioactive isotopes include

Sodium-24 (Na-24), Carbon-14 (C-14), Argon-41 (Ar-

41), and Potassium-40 (K-40). Most of our internal

exposure comes from K-40.

Radon (total average dose ~ 200 mrem/yr)

Radon comes from the radioactive decay of uranium,

which is naturally present in the soil.

Radon is a gas. It can travel through the soil and enter

through building foundation cracks. The greatest

concentrations of indoor radon are found in basements.

3) Radon emits alpha radiation. It presents a hazard only

Review characteristics of

when taken into the body (e.g., when inhaled).

alpha radiation.

Manmade sources

The difference between manmade sources of radiation

E01 Identify the major

and naturally occurring sources is the origin of the

sources of natural

source, i.e., where the radiation is either produced or

background and manmade

enhanced by human activities.

radiation.

The top sources of manmade radiation exposures are:

Tobacco products

Medical radiation

Building materials