Radionuclides are nuclides ( isotopes of elements ) with an unstable nucleus that change by radioactive decay into other elements, or other radioactive isotopes of the same element, which may or may not be stable.

Radionuclides can be divided into three types according to the radiation they emit:
Alpha emitters that emit helium nuclei ( alpha particles).
Beta emitters that emit electrons or positrons (beta particles).
Gamma emitters emit radiation in the form of gamma rays.
When a radionuclide emits radioactivity, it reaches a more stable state. It requires less energy than before and, as a rule, is mutated into a different nuclide (or the same, but less excited, if it has emitted gamma radioactivity). It can also be radioactive or not radioactive.
Naturally occurring radiative material (NORM) is material found in the environment that contains radioactive elements of natural origin.
This radioactive process occurs ad-lib in principle, but humans have learned to cause it artificially. In both cases, the resulting radioactivity has the same traits.
Ionizing radiation ( ion exchange) is radiation traveling as a particle or electromagnetic wave that carries sufficient energy to detach electrons from atoms or molecules, thereby ionizing an atom or a molecule.
How Is Radionuclide?
Radionuclides are characterized by having a finite half-life, ranging from small fractions of a second to thousands of years. In fact, some of them have such a long half-life that it has not yet been quantified on trial. There are even those that had been considered, and for specific practical uses, stable.
Of the nuclides currently known, ninety on paper are stable, and two hundred and fifty-five have not been observed to disintegrate.
On the other hand, there are almost twice as many, about 650, who have had radioactivity observed and have a half-life (at least one hour).
About 3000 radionuclides have a half-life more significant than one hour are known on Earth. Most of them (about 90%) are produced by humans. Some 2400 have a half-life less than one hour, and still others so unstable that their half-life is extremely short.
What Is the Use of Radionuclides?
Radionuclides are applied to nuclear energy technology to obtain electrical energy, in the industry (quality controls, etc.), nuclear medicine (radiotherapy, etc.), and for nuclear weapons (at the bottom to the push of vehicles and tools to kill).
Radionuclide's use implies serious environmental risks (nuclear waste) and health (radiotoxicity, radiation poisoning, etc.).
Radionuclides of natural origin, such as uranium or plutonium, exist in finite quantities on Earth, so they must be used sustainably. On the other hand, its use generates radioactive waste, which can be very dangerous. At present, the only treatment usually done is to cover them until their radioactivity is close to natural.
The possible dealing for those that would take more than thirty years to do so are still in the theory, research, or test phase. It is all spent nuclear fuel from nuclear power plants and for military purposes, for example.
Radionuclides in Food and Drinking Water
It has been proven that the harm from eating food that exceeds the permitted levels of radionuclides is more significant than from external radiation. When the radiation source is indoors, it has health effects on a person's internal organs, and therefore even a small dose of radiation can lead to serious health consequences.
Most radionuclides have properties close to those of these or other chemical elements that make up the human body. Therefore, the human body takes them for the parts it needs and retains them in the corresponding organs. Radionuclides in the organs continue to radiate, and it is already impossible for a person to protect himself from this radiation.
The main way of introducing radioactive atoms into the human body is through food and surface water, which has remained relevant for decades. It is explained by the fact that the most dangerous long-lived radionuclides, cesium-137, and strontium-90 enter the food. Due to their long half-life (about 30 years), these elements retain their activity for a long time. They are included in the food chain.