What is the cause of the negative impact of radiation on living things
The image of a black fan on a poisonous-yellow background is an international sign of radiation hazard. This sign denotes objects and devices that threaten radiation exposure: nuclear power plants, physical laboratories, places of burial of radiation waste, specialized medical equipment, etc.
Its authors were American atomic physicists who worked on the creation of an atomic and hydrogen bomb. Why did its creators choose such an image? The most acceptable version is an inverted shamrock - a symbol of the death of nature. We humans are part of this nature, what is the effect of radioactive radiation on living organisms?
Ways of penetration of radiation into the human body
When exposed to radiation on a person, he receives radiation. What are the ways of penetrating the radiation into the human body? There are two channels of radiation penetration into the tissues of the body.
- External irradiation emanating from cosmic rays, atoms of natural radioactive elements and products of their fission. Such a danger occurs in the testing of nuclear weapons and abnormal situations at nuclear power plants and other facilities. In this case, the dose of radiation is formed from x-ray and gamma rays, as well as beta particles of high energies.
- Internal irradiation caused by radioactive substances entering the body with food and water, through cuts and other skin damage, and also with inhaled air.
What kind of radiation is most dangerous for humans? It is internal irradiation that represents the greatest danger and more severe consequences for the human body.
This can be explained in the following way: the radioactive atom that enters the body comes into contact with the irradiated tissue and the time of action is limited only by the period of its stay in the human body. In addition, the local effect of radiation is enhanced, since radioactive substances are concentrated in the organs selectively.
Unfortunately, the methods of decontamination used for external irradiation are powerless here.
External and internal irradiation
What kind of radioactive radiation is most dangerous with external exposure of a person? External exposure affects a person only while they are in the radioactive zone. The danger is aggravated by the presence of neutrons in the spectrum of external radiation. These tiny particles, which do not have an electric charge, easily penetrate into the nuclei of atoms. As a result, atoms of new radioactive elements are formed. Thus, a source of secondary, already internal irradiation appears.
How does radiation affect the human body? Let us consider in more detail the processes that take place during external irradiation.
Some radioactive substances that enter the body through the skin enter the circulatory system and, together with the blood flow, are transferred to separate organs, creating high local foci of radiation.
The result of the penetration of radioactive substances together with respiration depends on the particle size. Most of them are eventually removed along with the exhaled air. The only exceptions are atoms entering into chemical bonds with bone tissue (uranium, zirconium, etc.).
As a result of exposure to radiation, the following diseases most often occur:
- external irradiation causes skin burns and mucous membranes of varying severity;
- irradiation of internal organs causes leukemia and tumor processes.
What is the cause of the negative impact of radiation?
The negative effect of radiation on living things is explained by the following reason: as a result of the strong ionizing effect of radioactive radiation, very active molecules, called free radicals, are formed in living cells. They are real aggressors for all body systems, damaging and killing living cells.
How do free radicals act on the human body?
- Their first "victims" are rapidly dividing cells of the gastrointestinal tract, hemopoietic organs, and also sex cells. Therefore, penetrating radiation can cause people to have a fever, nausea, vomiting, a decrease in blood cells and a loose stool.
- Organs and systems with a lower intensity of cell division undergo mainly dystrophic (qualitative) changes during irradiation.
- For the delicate tissues of our visual organs, irradiation is extremely dangerous - it can cause radiation cataracts.
- Another severe consequence of exposure is reduced immunity, vascular sclerosis and genetic changes.
Genetic effects of radiation
What are the genetic consequences of radiation? The mechanism of transmission of hereditary traits is a very delicate and sensitive structure. Errors and failures in this system can be caused by a number of causes, including radioactive radiation.
Transformations in genes (carriers of hereditary information) that occur when irradiated sex cells can cause changes (mutations) in the cells of a new organism. This negative effect can spread to subsequent generations. Offspring can develop physical and mental disorders. But these deviations can exist only on condition that the defective gene is connected to another gene having the same damage. The smaller the number of people exposed to radiation, the less likely the occurrence of such birth defects in offspring.
What the consequences of irradiation depend on
The result of exposure to radiation on living organisms depends on several factors:
- type of radiation;
- its intensity;
- from individual susceptibility.
The human body is capable of regenerating damaged cells until their number exceeds a certain critical level. If this limit is exceeded, irreversible processes are triggered, leading to severe consequences or even death.
The consequences of irradiation may not appear immediately, but after many years. Moreover, short-term, but intensive irradiation is more dangerous than its multiple, small doses.
To assess the radiation state, there are several parameters. The magnitude of the absorbed dose characterizes the ability of radiation to damage tissue cells. It is this parameter that determines the degree of radiation exposure. It is measured in Sievert (Sv).
A natural radiation background is always present in nature. The level of external irradiation, not exceeding 0.2 μS / h (microsievert per hour), is considered the norm of radiation for a person. This is the situation when they say "the radiation background is normal". Although there is a "no-threshold concept", according to which there is no safe dose of radiation exposure. The upper level of radiation to 0.5 μS / h is considered safe for the body, called the permissible dose of radiation for a person. This value is equivalent to 50 microroentgen per hour.
It is believed that by reducing the time spent in the danger zone, the human body transfers radiation with a power of 10 μS / h without harm to health. I mean fluorography, X-ray. X-ray picture of a sick tooth adds to this insidious "piggy bank" another 0.2 mSv. The figures below reflect only the potential danger. In fact, no type of medical examination can cause radiation sickness.
The total absorbed dose should not exceed a threshold of 100-700 mSv. A single dose of radiation of 6-7 Sv is considered absolutely fatal.
Do not tempt destiny - the natural instinct of self-preservation should work immediately when a sign of radiation hazard appears in your field of vision. The most reasonable thing is to immediately leave this zone. Remember, radioactivity has the ability to accumulate, and the dose of radiation - to summarize.