Background Radiation and the Dangers of Radiation

Examples of elements that emit ionising radiation all the time are: radon, uranium, astatine (halogen), plutonium and francium. The behaviour of radioactive materials cannot be changed by chemical or physical processes because radioactivity occurs due to an unstable nucleus, there is no involvement of electrons here. After the radioactivity has ended within an element, it should change to another element. For instance with carbon atoms, they randomly give out radiation once and what is left afterwards is a different element, usually referred to as a 'daughter product' or a 'decay product' element. It is a change inside of the atom, not a chemical change.

There are three types of energetic radiation that causes the nucleus to change once it is emitted. The following image shows their penetration properties:

http://pediaa.com/difference-between-alpha-beta-and-gamma-radiation/

Most of the background radiation we hear on a Geiger counter, is from natural sources. In fact, 84% is natural:

• 12% from cosmic rays which is ionising radiation from out space.
• 50% radon gas from the ground.
• 13% gamma rays from the ground and buildings.
• 9.5% from food and drink.

Some background radiation comes from artificial radiation:

• nuclear discharges
• medical reasons.

Radiation dose measures the possible harm the radiation can do to the body. It is measured in millisieverts (mSv). Sieverts show how radiation could be hazardous to humans. Sieverts take account the type and amount of radiation you've been exposed to. In addition, the damage to the body will also depend on the type of tissue affected. If Radon gas in inhaled, it is very likely to cause a great deal of harm to the lung tissue if they come in contact with each other, for lung tissue is easily prone to damage.

2 - 2.5 msV/year is the typical amount of background radiation experienced by all people. 100 msV is the lowest level at which the probability of cancer occurrence and the increase in cancer is evident.

Moreover, ionising radiation can be incredibly threatening to our health. It has the energy to knock of an electron from an atom, or it could make an atom gain an electron to thus become a positive or negative ion. The ionising radiation has the energy to break molecules in the cells in the body into ions. The ions can then take part is chemical reactions that are likely to damage the body. If the ionising radiation effects the DNA of the human body, this may lead to the cell being mutated or killed. If the cells mutate, then this could cause cancer.

There is no such thing as a 'safe dose' because just one radon atom could cause cancer. The chances are low, but there is always a risk. Radiation exposes humans to risk by either irradiation or/and contamination.

Exposure to a radiation source outside of the body is could irradiation. Alpha irradiation does not usually cause harm to the human cellular structure. This is because alpha particles only travel a few centimeters in the air, and they are easily absorbed. Irradiation by beta particles is more risky because they can penetrate a few centimeters into the body. Most gamma rays pass through the body but if they are absorbed, their high energy retention can cause some huge threats towards cells within the body whether it be skin, or heart cells. 

If a radiation source enters your body, or gets on skin or clothes, it is called contamination. If you swallow or breathe in any radioactive material, your vital organs will be exposed to continuous radiation for a long time. Alpha particles are the most ionising so contamination can cause cancer very quickly or kill cells. Contamination by gamma is less threatening because it could just pass through the body due to its high penetration. So, irradiation and contamination occurs to most if not all humans because of background radiation. 

Categories of people at higher risks of being exposed to radiation include those who work in a nuclear power plant or miners. Uranium minders and processors workers in nuclear power plants are constantly being exposed to the radioactivity of uranium. Airline staff usually are in contact with cosmic rays and miners suffer from radioactive rocks. Nuclear researches also find themselves near the constant nuclear waste, releasing radiation and medical staff like radiographers find themselves being exposed to x-rays, which is a form of ionising radiation that is apart of the electromagnetic (EM) spectrum.

In the UK, people who tend to have higher doses of radiation are carefully monitored and have regular health check-ups to make sure they are not becoming ill as a result of radiation they are exposed to whilst working.