Part 1 of 4 Parts
I have blogged often about the radiation threats from nuclear reactors, nuclear waste, nuclear weapons, etc. On the other hand, we may be exposed to different types of radiation from common everyday sources. The term radiation is very broad and covers a variety of specific types of radiation emitted from various sources. I am going to go over the different things that are referred to as “radiation” before dealing with possible sources.
There are several different types of atomic particles, either single or in combination that are classified as radiation. Helium ions with two protons and two neutrons are a type of radiation called alpha particles. They can cause serious damage to tissue but are easily blocked by even a single sheet of paper. They have to be either consumed or inhaled in order to be a health threat. Highly energetic electrons are radiation referred to as beta particles. They are also easy to block with a few millimeters of aluminum, wood, plastic, water of acrylic plastic. Beta particles cause less damage to tissue than alpha particles. Neutron which are emitted as part of radioactive decay processes can damage tissue. Cosmic rays are highly energetic nuclei of all natural elements that are generated by a variety of processes in outer space.
The entire electromagnetic spectrum consists of radiant energy. Of particular interest are the following frequency bands. The band used by cell phones has a frequency of about a billion cycles per second. Unfortunately, this happens to be the exact band of electromagnetic radiation absorbed by the human brain. The terahertz band which is used in airport scanners has a frequency of about ten followed by twelve zeros and is considered relatively harmless. It lies between the bands of microwaves and infrared. Ultraviolet radiation is above the visible light band. UV from the sun can burn exposed human skin. UV has frequencies from ten followed by fourteen zeros to ten followed by sixteen zeros. X-rays which are used in medical diagnosis have a frequency of about ten followed by seventeen zeros. Gamma rays which are extremely energetic high frequencies of electromagnetic radiation have a frequency above ten followed by nineteen zeros.
Here are some common sources.
Bananas are often mentioned in the context of common radiation emitters. They contain the radioactive isotope potassium-40. Potassium-40 emits beta particles and gamma rays as it decays. The amount of radiation from one banana is roughly equivalent to average levels of background radiation. However, a truckload of bananas can set off the radiation detectors at U.S. ports of entry.
Brazil nuts grown in Brazil turn out to contain radium drawn up by the very deep roots of the trees that grow the nuts. The soil in Brazil is naturally high in radium. Radium emits alpha particles, beta particles and gamma rays. The amount can be a thousand times the amount in most other foods, but it is still low enough not to pose a significant health threat.
Please read Part 2