Student 4: High Achieved
Alpha Radiation
Most forms of alpha particles cannot penetrate the skin. However, they can be harmful when
inhaled, swallowed or absorbed through wounds. Alpha particles are heavier and have a greater
mass than other radioactive particles. Alpha particles are strongly ionising, therefore they are easily
absorbed and cannot travel far in the air (about 6cm), or through substances such as plastic.
Beta Radiation
Beta particles are able to penetrate skin to the germinal layer (where new skin is made) therefore
they are able to cause damage to cells. Beta particles are lighter and have smaller mass than Alpha
particles. Beta particles also have lower ionising level than Alpha particles so they are able to travel
further in air before their electrons are stripped from their orbit, and they have a moderate
penetrative ability.
Gamma Radiation
Gamma particles are able to travel many inches into human tissue having the potential to cause a lot
of damage to skin and things like gene mutations. Gamma particles have very small mass and are
very light. They have lower ionising ability than alpha particles so they can travel further into
substances 30 cm into steel.
The explosion at Chenobyl pushed the radiation into the atmosphere, which was further spread over
a massive area by the wind. This means that a huge amount of people and land were contaminated
by the radioactive substances – an area of 150,000Km2, contaminating the populations of Belarus,
Russia and Ukraine. The radiation consisted of subatomic particles that could easily penetrate
human skin, thus damaging biological cells and causing genetic defects and cancer.
The nuclear reactor still remains a serious threat to Europe due to the long lives of the radioactive
materials that were released into the atmosphere. Over 100 elements were released, some with
long half-lives, including iodine (8 days), strontium (29 years), and the most dangerous, caesium (30
years). As the radioactive substances have such long half-lives, they are still present in the
atmosphere even after 25 years. Therefore, they are still able to penetrate human skin and cause
damage to cells.
The radioactive substances released have been linked to cancers. This is due to their penetrating
ability. Those susceptible to a high uptake of radioactive iodine showed an increase risk of thyroid
cancer, particularly in children. Strontium has been linked to Leukaemia. Caesium has been shown
to increase the risk of cancer in the liver and the spleen.