Radiation is the ionizing radiation of microscopic particles and physical fields. Radiation radiation does not include ultraviolet rays and the visible light range. Radio waves and microwaves do not have the ability to ionize the oncoming substance; this is not radiation. The lethal dose for humans is not created artificially by chemical processes, radiation is a physical effect.
Power and dose
The power of radiation is the amount of ionization for a certain time period. For power, there is a unit of measurement - microroentgen per hour.
The received dose is measured by the total dose, determined by the radiation power, multiplied by the time of action of the microparticles, thus, the lethal dose of radiation for a person, which leads to death, is calculated. Sievert (Sv) is used to measure the equivalent dose, the power for calculation is determined in sieverts per hour (Sv/h).
To calculate the equivalent dose from exposure to rays of various types, the intensity of the desired radiation in relation to the sievert is taken into account. For example, when determining the total dose from the action of gamma rays, 100 roentgens are equated to1 Sound Small doses, less than 1 Sv are calculated in relation to:
- 1 mSv (millisievert) is equal to 1/1000 sievert;
- 1 µSv (microsievert) is equal to 1/1000 millisievert or 1/1000000 sievert.
Emission Meter
A dosimeter is a standard widespread device for determining the dose rate or power directed at the device and the operator of the device. Dosimetry is carried out during the time of exposure to radiation, such as a work shift or rescue work.
The lethal dose of radiation for a person in roentgens depends on the intensity of radiation at the location of the worker, if the total figure is more than 600 units, then such exposure is life-threatening. The transported goods and objects are examined, the background from buildings and buildings is measured. Each person visiting places with a risk of radiation contamination acquires a dosimeter for permanent personal use.
When going to an unfamiliar area, for example, mountains, lakes, going hiking or picking berries and mushrooms, they take a device to survey the area before a long stay. The radiation intensity of the site is determined before construction or when buying land. The radiation background does not decrease and is not removed from the walls of buildings and objects, therefore, the danger is preliminarily detected using a dosimeter.
The concept of radioactivity
Some atoms contain unstable nuclei capable of transforming orfall apart. This process promotes the release of free ions. There is radioactive radiation, energetically powerful, capable of influencing the surrounding matter and provoking the appearance of new ions of negative and positive charge. The lethal dose of radiation in rad occurs when a person is exposed to 600 rad, while 100 rad (non-systemic unit)=100 roentgens.
Causes of radioactive contamination
The action of various factors and circumstances causes an increased radiation background:
- precipitation of a radioactive substance from a nuclear cloud during an explosion;
- when induced radiation occurs, obtained by the formation of radioactive isotopes under the instantaneous action of gamma rays and neutrons released during a nuclear explosion;
- effect of external radiation of gamma and beta rays;
- lethal dose of radiation is manifested by internal exposure after radioactive isotopes enter the human body from the air or with food;
- radioactive contamination is provoked in peacetime by man-made disasters at nuclear facilities, improper transportation and disposal of nuclear waste.
Type of radiation
Dangerous for humans is the radiation of microparticles, leading to diseases of the body and deaths. The magnitude of exposure depends on the type of rays, duration of action and frequency:
- heavy alpha particles, positively charged after the decay of nuclei (these include thoron, cob alt-60, uranium, radon);
- beta particles are ordinary electrons of strontium-90, potassium-40, cesium-137;
- gamma radiation is represented by particles with high penetrating power (cesium-137, cob alt-60);
- hard X-rays, reminiscent of gamma particles but less energetic, provided by americium-241, a constant source of origin is the sun;
- Neutrons are produced as a result of the decay of plutonium nuclei, their accumulation is observed in the environment of nuclear reactors.
Varieties of doses
Equivalent fixed effective dose is the determination of radiation doses to the body as a result of the intake of a certain amount of a harmful substance. This indicator takes into account the sensitivity of the internal organs and the time spent by the radioactive substance in the body (sometimes throughout life). In some cases, the lethal dose of radiation in roentgens is measured for one selected organ.
The ambident dose equivalent is determined by the amount that a person could receive if he were present in the area where dosimetry is done, the indicator is measured in sieverts.
The impact of radiation pollution on the human body
Any radiation that leads to the formation of electrical particles with different signs in the environment is considered ionizing. The scattered radiation background constantly accompanies a person, it is created by cosmic radiation, the influence of the sun, natural sources of radionuclides, and other components of the biosphere.
For work inhazardous conditions, personnel are protected by special suits, safety standards are observed. The body receives radiation at the workplace during physical and chemical experiments, flaw detection, medical research, geological surveys, etc.
Irradiation mutation
The lethal dose of radiation for a person in rad is over 600 units and is fatal. Irradiation at a dose of 400 to 600 rad contributes to the appearance of radiation sickness and can cause gene mutation. The action of the ionized transformation of the body is little studied, mutations manifest themselves through generations. The spread of time gives the right to doubt whether the mutation appeared from radioactive influence or was caused by other reasons.
Mutations are divided by type into dominant, appearing in a short period after exposure to radiation and recessive. The second type manifests itself if the mother and child have one mutant gene. The mutation does not wake up for several generations or does not bother a person at all. The degeneration of the fetus is difficult to determine in the case of preterm birth, if the mutation does not allow the fetus to reach childbirth.
Radiation sickness. Leukemia
Radiation plays a big role in diagnosing radiation sickness. A lethal dose of radiation leads to death, but no less dangerous are levels of radiation from 200 to 600 r, which cause radiation sickness. Radiation affects a person after a single powerful exposure or with constant penetration of radiation of low power. An example is the work of radiologists who cannot withstand constant exposure and fall ill with characteristic diseases.
The most dangerous is the effect of radiation on a fragile body up to 15 years. There is no consensus on the size of the dose, the researchers give different tolerance doses of 50, 100 and 200 r. Pathogenesis is being studied in research institutes, radiation leukemia is becoming more accessible for treatment.
Cancer
Studying the effect of radiation on a person is difficult because large groups of people are studied in order to obtain generalized data, which is impossible without a special experiment. What lethal dose of radiation is lethal, and what levels cause human oncological tumors cannot be judged by experiment on animals.
In the sense of isolating a dangerous dose that causes cancerous tumors, there are no definite data. Any dose of radiation received gives an impetus to the body to start dividing aggressive cells. According to the frequency of manifestation of the disease, they are divided as follows:
- the most common manifestation of leukemia;
- out of 1000 women at risk, 10 patients get breast cancer;
- same thyroid cancer statistics.
Severity of radiation sickness
Symptoms of radiation sickness are constant headache, impaired movement, coordination of gestures, nausea, vomiting, dizziness,disorders of the stomach and intestines. What dose of radiation is lethal to humans:
- first degree appears after a latent period of two weeks, the disease is caused by radiation from 100 to 200 roentgens;
- for manifestation of the second degree after irradiation with a dose of 200 to 400 roentgens, death occurs in a quarter of those exposed to radiation;
- the third stage of radiation sickness is mortality in 50% of cases, for the occurrence of a sufficient dose of radiation from 400 to 600 roentgens;
- The fourth, most dangerous stage is also caused by radiation. The lethal dose is more than 600 roentgens, death occurs in 100% of cases.
Methods of personal protection in case of radiation contamination of the area
Defined standard actions for the population if there is radiation in the territory. The lethal dose of radiation is life-threatening, therefore, in order to reduce deaths, people are evacuated to facilities that, according to the degree of protection, are divided into capital bomb shelters, basements, wooden buildings and cars. The first type of building protects best, the rest are considered as emergency temporary shelters.
Effective measures include respiratory, water and food protection. Shelter of essentials is done in advance if there is a danger of a blowout or explosion. They use anti-radiation medicines, do not use fresh milk for food.
Regular sanitization anddisinfection of the area, at any opportunity, people are evacuated outside the infected area. Reducing internal exposure by eliminating dust entrapment is provided by respirators that are effective in 80% of cases. A gauze bandage of four layers gives a lower indicator, but they use all the means of protection at hand. As a cape, water-repellent raincoats are used, in extreme cases, plastic wrap.
In conclusion, it should be mentioned that the radiation contamination of the area is not decreasing, the risk of human infection is minimized by the use of personal protective equipment and control of the received radiation dose using dosimeters.
