Alpha radiation is a type of energy released when certain radioactive elements decay or break down.
For example, uranium and thorium are two radioactive elements found naturally in the earth s crust. Over billions of years, these two elements slowly change form and produce decay products such as radium and radon. During this change process, energy is released. One form of this energy is alpha radiation. Because the earth s bedrock contains varying amounts of radioactive elements, the amount of alpha radiation in water also varies.