Radioactivity is the process by which the nucleus of an unstable atom loses energy by emitting alpha particles, beta particles, gamma rays in ionizing radiation. When the nucleus of an element with an atomic number greater than 82 is struck by a fast-moving neutron, the nucleus emits spontaneously high-resolution radiation. This radiation is radioactive radiation.

In 1896, while studying X-rays, the French scientist Henri Becquerel discovered a spontaneous natural phenomenon which caused a great stir in the world of science.

He observed that the nucleus of uranium metal emits a ray of special energy spontaneously. This ray is named after him Beckerel ray. He observes that the emission of this ray continues until the element from which this ray is emitted is transformed into a completely new element.

Later, Madame Curie and her husband, Pierre Curie, conducted extensive research and found that the nuclei of heavy elements, such as radium, polonium, thorium, and actinium, emitted the same type of radiation as the Beckerel ray, now known as radioactive rays. The elements from which radioactive rays are emitted are called radioactive elements.

Though it's a nuclear phenomenon, no ordinary external physical process, such as pressure, heat, electricity, or magnetic field, can prevent or increase the activity of radioactivity.

However, it is possible for nuclear reactions to take place in extreme conditions, such as very fast neutrons or intense temperatures like the interior of the sun, or pressure during a supernova explosion. The time at which exactly half of the total atoms of a radioactive substance is lost is called the half-life of that substance.

The unit used to measure radioactivity is called Becquerel. A radioactive fraction or radioactive decay per second is called a Becquerel. Radiation is measured in three ways for three steps. When it comes to radiation in nuclear reactors and radioactive elements, the amount of radiation from the source is needs to be determined. This amount is expressed in Becquerel or Curie.

37,000,000,000 radiations per second is called 1 curry. Depending on the distance from the source, human age, physical constitution, radiation grade, time, etc., the response to radioactivity may vary from person to person and from object to object.

The source of radioactivity can be divided into three categories: natural, man-made, and the surrounding environment. a) Natural Sources: - The nuclei of electrons, protons and a few atoms from all over the world hit the earth at the speed of light. These are called cosmic rays. These rays are electrically charged. Natural radioactivity penetrates the atmosphere in small amounts and travels to the surface.

The most important of the natural sources is radon gas. It is 8 times heavier than air. It has three natural isotopes. These are caused by the radioactivity of radium, uranium and thorium. In addition, radon gas from natural rocks, plants, animals and various industries is added to the atmosphere.

b) Man-made: Medical X-ray and other radiation therapy machines are significant sources of radioactivity. In the industrial field, various components are used to increase production and to verify the quality of the product which produces hazardous radiation.

Military nuclear reactors, nuclear weapons tests and nuclear power plants can spread large amounts of radioactive material in the surrounding area through various accidents.

c) Surrounding environment: Almost every object around us is radiating. Radiation is also being emitted from our homes, food and drink. This radiation is in very low levels, which is not harmful to humans.

The scope of use of radioactive rays is constantly increasing. For example, in the treatment of cancer, in the study of improved seed production, in the determination of the amount of various metals in minerals, the radioactive isotope of that metal is used as a radioactive indicator, determining the age of fossil specimens and rocks, in the generation of electricity through turbines and generators, in the construction or manufacturing industry and by utilizing the heat energy generated in the fission process to determine the exact amount of density of various materials like paper, plastic and aluminum.

As consumption increases, so does the risk of radioactivity. This ray causes a deadly reaction in the organism. High levels of radioactive radiation can cause a variety of cancers in the human body. Prolonged exposure to excessive amounts of radioactive radiation weakens a person's immune system and can lead to mental retardation and even disability.

Its detrimental effects are also observed in the lineage. For example, the effects of radioactivity can lead to the birth of a handicapped child. Radioactive waste is a threat to human civilization.

Radioactive pollution is a type of invisible pollution that is extremely harmful to humans. The source of radioactivity is the sun and space, from where it reaches the earth.

Most of the harmful radioactivity comes from various radioactive substances, especially from the detonation of nuclear weapons, nuclear power plants and various types of electronic materials. Notable among these are laser beams, X-ray machines, color television sets, microwave ovens, etc.

The harmful effects of radioactivity can be seen in the formation of cells. If the radioactive cells die or heal on their own, there is no problem later. But a damaged cell later becomes prone to cancer. When human gametes are damaged by radioactivity, they become infertile, and newborns are at risk of becoming disabled or mentally ill.

In Bangladesh solid and liquid radioactive waste is usually generated from research, industry, education, agriculture, medicine etc.

Radioactive waste from a variety of sources contains a certain amount of radioactivity, and if not properly managed, it can have serious effects on the human body and the environment.

Different types of solid radioactive waste, such as: ion-exchange resins, graphite plugs, metallic products, contaminated vials, hand gloves, plastic syringes, shoe-covers, protective cloths, plastics and metallic wires, etc. generates different radiation from installations.

 Besides, radioactive waste is generated from various government and private medical college hospitals, fertilizer factories, paper mills etc.

The problem of radioactive waste removal around the world has caused serious concern. The dumping of radioactive waste into the deep sea has caused a great deal of panic for those living around the ocean. The people of South Asia are increasingly concerned about the dumping of radioactive waste in the Bay of Bengal.

The current situation is such that the pollution caused by the production of nuclear energy has caused panic and concern among the people of the world and there is a need to form public opinion against the use of nuclear energy in the interest of the security of mankind and the animal kingdom as a whole.

Some personal awareness is also important to prevent radiation. For example: avoiding exposure to strong sunlight, trying to avoid rain water as much as possible, eating foods rich in chlorophyll and oxidants, using iodine in food, using sun-glass when going out during the day, avoiding taking excessive radiation therapy, staying away from all machines that do X-rays and radiation and coveing the body when going out during the day or using sun-lotion or cream.


Writer: Columnist & Asst. Officer, Career & Professional Development Services Department, Southeast University.