One of the major source of environmental concerned with the production of nuclear power which releases radioactive substances in the environment. Radioactive pollution is a special form of physical pollution related to major life supporting systems Such as air, water and soil. A number of atoms possess the ability to emit radiation’s and thereby cause radioactive pollution.
Radioactive pollution is very much different from the other types of pollution. Simply because its nature of contamination is different from others. Besides the effects are also different. Radioactivity is a phenomenon of spontaneous emission of protons (alpha particles), electrons (beta particles) and gamma rays (short wave electromagnetic waves) as a result of disintegration of atomic nucleus of some elements.
Sources of radiations exposure to plants, animals and humans can be grouped into two main types:
I. Natural Sources of radiation
II. Man-made sources of radiation
(I) Natural Sources of Radiation:
Nuclear reactions have produced a large number of unstable nuclei or isotopes which lose subatomic particles and emit high energy radiations to acquire a stable state. This process continues and constitutes an important source of radiations for the biosphere. In addition earth’s surface is regularly irradiated by X-rays, cosmic rays and ultraviolet rays from outer space and terrestrial radiations from radio nucleides. Uranium -238, thorium -232, radon -222, potassium -40 and carbon -14 occur naturally in rocks, soil and water.
(II) Man-made Sources of Radiation:
Man- made sources of radioactivity include nuclear reactors, diagnostic and therapeutic application of radioactivity, atomic tests and weapons and miscellaneous industrial uses of radioactive materials. Man-made sources of radiations are mining and refining of plutonium and thorium, production and explosion of nuclear weapons, nuclear power plants fuels and preparation of radioactive isotopes.
Medical and diagnostic uses of radioactivity are the most important source of radiation to general public. There are numerous X-ray clinics and hospitals where radioactive isotopes of cobalt and iodine etc. are frequently used for diagnotic or curative purposes in the treatment of cancer and hyperthyroidism. Colour televisions, computer screens, videogames are also sources of radiation to general public.
Explosion of two atomic bombs in Nagasaki and Hiroshima killed innocent people, animals and damaged plants. Explosions are uncontrolled chain reactions which give rise to very large neutron flux condition which make other materials in the surroundings radioactive. These materials include Strontium-90, Cesium- 137, Iodine-131 and unused explosive and activation products.
The radioactive materials are transferred into gases and fine particles which are thrown high up into the air like a mushroom cloud. The radioactive materials are carried away by the mud and spread to wide areas.
These particles settle down to cause water and soil pollution. With rain drops falling on the ground radioactivity is transferred to the soil. It is from such soil, the radioactive substances enter the food chain, thus, affecting different forms of life. The aquatic organisms absorb and accumulate the radioactive materials.
The fuel element and coolants of operation of a nuclear power contribute to radiation pollution. The main problem is concerned with the disposal of radioactive waste. It is these wastes which provides public hazard wherever they are dumped. The radioactive nuclides are sources of radiation.