Radiation Basics 8
Radioactivity is definitely a threat to our health. It has been said that there is no safe minimum dose of radiation but we seem to survive in a natural environment with many different sources of radiation both outside and inside our bodies. On the average, there are over 800 radioactive events in the human body every second. Here is a list of the radioactive isotopes in our bodies.
(There are 28.3 grams in one ounce, one thousand milligrams in a gram, on million micrograms in a gram, one billion nanograms in a gram, one trillion picograms in a gram, and one quadrillion femto grams in a gram, and one thousand grams in a kilogram)
Potassium-40 - 16.5 milligrams - 4,340 disintegrations per second
Carbon-14 - 16 nanograms - 3080 disintegrations per second
Rubidium-87 - 190 milligrams - 600 disintegrations per second
Lead-210 - 5400 picograms - 15 disintegrations per second
Helium-3 - 20 femtograms - 7 disintegrations per second
Uranium-238 - 100 micrograms - 3-5 disintegrations per second
Radium-228 - 46 femtograms - 5 disintegrations per second
Radium-226 36 micrograms - 3 disintegrations per second
The uranium, potassium and rubidium in our bodies were created in stellar explosions before the Earth was formed. The lead and radium isotopes were created by thorium and uranium decay. Helium-3 and Carbon-14 are being continuously created by cosmic rays bombarding the atmosphere of the Earth.
Potassium-40 is present in all the food that we eat in tiny quantities. Potassium is abundant in our environment and plants take it up from the soil. We consume about two and one half grams of potassium every day. It is an essential part of our diet and our bodies maintain a constant level.
Carbon-14 makes up a tiny amount of the roughly 16 kilograms of carbon in our bodies. It is constantly being created by cosmic rays interacting with nitrogen in the atmosphere. All living things breath in tiny amounts of carbon-14 as their bodies constantly replace carbon. Carbon-14 can be used to date the age of a biological material because when something dies, it stops taking in carbon-14 which decays and slowly disappears.