Radioactivity is a phenomenon of spontaneous emission of particles such as protons (alpha particles), electrons (beta particles), and gamma rays (short wave electromagnetic radiation) due to the disintegration of atomic nuclei of some elements.
The natural environment has radioactive radiation but these radiations are present in a quantity which can be easily tolerated by living organisms. However, with the development of Nuclear Technology for electricity generation, medical uses or Weapon of mass destruction, there is a constant threat of radioactive pollution if any of the safety standards fail to prevent leakage of radiation to the outer environment.
Types of Radiation
- Non-ionising radiation: It affects only those components which absorb them and have low penetrability.
- Ionising radiation: It has high penetrability and causes the breakage of macro-molecules.
- Alpha Particles: It can be easily blocked by human skin and so is not harmful.
- Beta Particles: It can penetrate human skin but can be blocked by using metals or glasses.
- Gama Rays: It is the most harmful as it can easily penetrate human skin and damage the human cells. It can only be blocked by massive concrete structures.
Sources of Radioactive Radiations
- They include cosmic rays from space and terrestrial radiations from radio-nuclides present in earth's crust such as radium-224, uranium-238, thorium-232, potassium-40, carbon-14 etc.
- Nuclear power plants
- Nuclear weapons
- Transportation of nuclear material
- Disposal of nuclear waste
- Uranium mining
- Radiation therapy
Effects of Radioactive Radiation
The effects of radioactive pollutants depend upon the following factors,
- Energy releasing capacity
- The rate of diffusion and
- The rate of deposition of the pollutant
- various environmental factors such as wind, temperature, rainfall also influence their effects
The effect of radiation also depends on the type of radiation waves
Effects of non-ionizing radiation
- They include short-wave radiations such as the ultraviolet rays which form a part of solar radiation.
- They have a low penetrating power and affect only the cells and molecules which absorb them.
- They can damage eyes which may occur due to reflection from coastal sand, snow (known as snow blindness) or by directly looking at the sun during an eclipse.
- They can injure the cells of skin and blood capillaries producing blisters and reddening. This condition is known as sunburn.
Effects of ionizing radiation
- They include x-rays, gamma rays, cosmic rays and other atomic radiations caused by the emissions of radioactive elements.
- Ionizing radiation has high penetration power and can cause a breakage of macro-molecules
- The molecular damage may produce short range (immediate) and long range (delayed) effects.
- Short range effects include burns, impaired metabolism, dead tissues and death of several organisms.
- Long range effects include mutations leading to increased incidence of tumours and cancers, shortening of life-span and developmental changes. The mutated gene can persist in living organisms and may affect their progeny.
- The actively dividing cells such as the embryo, foetus, cells of the skin, intestinal lining, bone marrow and gamete forming cells are more sensitive to radiation.
Prevention is the best control measure as there is no cure available for radiation damage.
- All safety measures should be strictly enforced. Leakage of radioactive elements should be totally checked.
- Safe disposal of radioactive waste.
- Regular monitoring through frequent sampling and quantitative analysis.
- Safety measures against nuclear accidents.
- Nuclear explosions and use of nuclear weapons should be completely banned.
- Appropriate steps should be taken to protect oneself from occupational exposure.