The light source is divided into:
chemical source
Photoluminescent
Radioluminescent (phosphor 31)
Incandescent lamps (Lodygin)
Discharge lamps (Yablochkov)
Semiconductor light sources (LEDs) (Alferov)
Non-electric sources
Characteristics of light sources:
Rated voltage (usually 220 or 127)
Lamp power
Rated luminous flux [F nom ]
Color design of industrial interior. Performance to a certain extent depends on the color design.
Red color - excites
Orange - invigorates
Yellow - fun
Green - soothes
Blue - regulates breathing
Black - sharply lowers mood
White - causes apathy
Noise and vibration
The impact of noise on human activity.
Noise– any unwanted sound that has a harmful effect on the human body.
Noise damage:
Reduces attention
Impairs reaction
Depresses the nervous system
Promotes metabolic disorders
noise sickness– occupational disease (some organs cease to function due to noise).
Sound vibrations are divided into:
Infrasound (less than 20 Hz)
Audible (20 Hz to 20 kHz)
ultrasonic range
Low frequency (20 to 400 Hz)
Average frequency (from 400 to 1000)
High Frequency (1000 to 4000)
Intensity- the ratio of power to the area of transferred energy. [W/m2]
sound wave pressure(measured in pascals).
The increase in the power of sensation
Measured in Bels
Noise regulation
Normalized by:
Limit spectrum (constant noise)
Equivalent noise level (intermittent noise)
Up to 35 dB - does not bother a person
40 to 70 causes neuroses
Above 70 dB leads to hearing loss
up to 140 causes pain
over 140 death
Noise protection
Reducing the sound power of the noise source
Noise redirection
Rational layout of production sites
The most rational way to reduce noise is to reduce the sound power of its source. The reduction of mechanical noise is achieved by: improving the design of mechanisms; replacement of metal parts with plastic ones; replacement of impact technological processes with non-impact ones.
The effectiveness of these measures to reduce the noise level gives an effect of up to 15 dB.
The next way to reduce noise is to change the direction of its radiation.
This method is used when the operating device emits noise directionally. An example of such a device is a pipe for discharging compressed air into the atmosphere in the direction opposite to the workplace.
Rational planning of enterprises and workshops. If there are several noisy workshops on the territory of the enterprise, then it is advisable to concentrate them in one or two places, as far as possible from other workshops and residential areas.
The next way to deal with noise is associated with a decrease in sound power along the path of noise propagation (sound insulation). In practice, this is achieved by using soundproof enclosures and casings, soundproof booths and control panels, soundproof and acoustic screens.
As materials for soundproof fences, it is recommended to use concrete, reinforced concrete, brick, ceramic blocks, wooden sheets, glass.
Soundproof casings usually completely cover the noise-producing device. Casings are made of sheet metal (steel, duralumin) or plastic. As with soundproof enclosures, enclosures are more effective at reducing noise at high frequencies than at low frequencies.
5. Sound absorption. IN industrial premises the sound level increases significantly due to the reflection of noise from building structures and equipment. To reduce the level of reflected sound, a special acoustic treatment of the room is used using sound absorption means, which include sound-absorbing linings and piece sound absorbers. They absorb sound. In this case, the oscillatory energy of the sound wave is converted into heat due to friction losses in the sound absorber.
For sound absorption, porous materials are used (i.e., materials that do not have a continuous structure), since friction losses in them are more significant. Conversely, soundproof structures that reflect noise are made of massive, hard and dense materials.
Individual protection means
Ear plugs (reduce up to 20 dB)
Earbuds (up to 40 dB)
Helmets (up to 60-70 dB)
Vibration. The impact of vibration on life
Vibration are mechanical vibrations of a rigid body around the equilibrium position.
From a physical point of view, vibration is an oscillatory process, as a result of which the body passes through the same stable position at certain intervals.
Frequency characteristics of vibration:
Frequency range for general vibrations (F=0.8*80Hz)
Average geometric frequencies (1, 2, 4, 8, 16, 32, 63 Hz)
Frequency range for local vibrations (from 5 to 1400 Hz)
SNG (8, 16, 32, 63, 125, 250, 500, 1000)
Absolute vibration parameters
Amplitude [A] [U] is measured in meters
Vibration velocity [V] m/s
Vibration acceleration [a] m/s 2
Relative vibration parameters
Vibration velocity level
α v =20Lg(V/V 0) [dB]
V 0 =5*10 -8 m/s Threshold value
Vibration acceleration level
α a \u003d 20Lg (a / a 0) dB
Vibration is divided into two types:
Local vibration (acts on individual parts of the body)
General vibration (acts on the entire body through the supporting surfaces (floor, seat)).
Vibration is very dangerous for the body. When external vibrations and vibrations of the body coincide, a resonance occurs (6-9 Hz).
Vibration disease (not treated):
Stage 1: change in skin feelings; pain and weakness in the bones; changes in blood vessels
Stage 2: violation of skin sensitivity; spasms of the fingers
Stage 3: atrophy of the shoulder girdle; changes in the central nervous system (central nervous system) and CCC (cardiovascular system)
Sources of vibration
In accordance with SSBT (GOST 12), vibration sources are divided into:
Transport sources (road, rail and water)
Transport and technological (cranes, excavators)
Technological (machines, compressors and pumps)
Manual cars
Hand tool
Local
Vibration regulation
Vibration is normalized in accordance with sanitary standards (industrial vibration, vibration of residential and public premises).
Vibration is normalized according to two indicators:
Vibration local
Vibration general
Both vibrations are normalized by the speed level in dB.
Very often both noise and vibration are normalized at the same time.
Noise is normalized:
By equivalent sound level
According to the sound pressure of infrasound
According to the sound pressure of air ultrasound
According to the level of vibration velocity of ultrasound.
4) Vibration protection
Vibration damping (vibration damper) Mechanical energy is converted into thermal energy
Vibration damping (array, foundation)
Vibration isolation (room isolators)
Vibration reduction at the source
Vibration reduction along its propagation path
Individual protection means
The main personal protective equipment is vibration-proof shoes and vibration-proof gloves
Compliance with the regime of work and rest
The degree of impact of vibration on a person depends on the time of continuous operation of the vibro tool. Doctors have established that every 30 minutes to take breaks for 10-15 minutes, then vibration sickness can be avoided.
Electromagnetic radiation (EMR)
The impact of electromagnetic radiation on humans.
Non-ionizing electromagnetic radiation includes:
Ultraviolet radiation
visible light
Infrared radiation
radio waves
Ionizing species include x-rays and gamma rays.
From the point of view of life safety, non-ionizing electromagnetic radiation is divided into three groups:
EMF (electromagnetic radiation) radio frequencies
EMF (electromagnetic radiation of industrial frequency)
Permanent magnetic fields
Radio Frequency Electromagnetic Emissions
Basic parameters of electromagnetic radiation:
Sources of electromagnetic radiation:
microwaves
Mobile and radio telephones
Computers
Radio engineering objects
Radios and Cellular Base Stations
Thermal shops
household sources
Zones of influence of electromagnetic fields(often in an exam)
(impact is characterized only by the energy flux density [I])
Human exposure to electromagnetic radiation is associated with a thermal effect. Electromagnetic radiation (EMR) - transfers a certain amount of energy to the human body, this energy is converted into heat up to a certain limit, the body removes this heat, when it ceases to cope with heat removal, the person becomes ill.
Organs that are more susceptible to EMR: eyes; brain stomach liver
Symptoms: fatigue and changes in the blood, then tumors and allergies occur.
Rationing of the electromagnetic environment
SanNPiN 2.2.4. 191-03 - electromagnetic fields in industrial conditions
TRL of the earth's magnetic field
Maximum permissible levels of magnetic fields
Maximum allowable levels of electrostatic fields
Maximum permissible levels of electric and magnetic fields of industrial frequency
Maximum permissible levels of electromagnetic fields (by range)
Energy flux density - in the CIS
In the USA, the characteristic is the specific power absorption
Electromagnetic safety
It is carried out by the following methods:
Reflective (Foucault currents dampen these waves)
Absorbent
time protection
distance protection
Protection by rational compensation of the source of ionizing radiation
Reducing the power of sources of ionizing radiation
Shielding
The use of personal protective equipment (gowns with a metal base)
Cell Phone Rules
The energy flux density of a mobile phone in the brain area is (16 W / m 2 exposure per minute, and the allowable rate is 10 W / m 2)
The greatest power occurs at the time of the call
Ear distance (do not lean too hard)
Transferring from hand to hand (i.e. from one ear to the other)
Using headphones (headset)
Harmful factors that arise when working with a computer
Working posture and lighting
Heat (infrared radiation)
Noise and vibration
Static electricity
electromagnetic fields
Security measures:
Compliance with the ergonomics of the workplace (convenient location and lighting)
Microclimate (temperature should not exceed 35 degrees; humidity 65%, air from 0.1 to 02 m / s)
Room volume (at least 20 m2 per user)
Air volume (at least 20 m 3 / hour)
Distance to the display (at least 60 cm)
Rest time (10 minutes per hour)
Radiation safety
Types of ionizing radiation
Radiation refers to ionizing radiation.
ionizing radiation- this is the radiation whose interaction with the medium leads to the formation of ions.
Ionizing radiation is divided into:
Characteristics of sources ionizing radiation. (Activity)
A source of ionizing radiation is a substance and installation, the use of which produces ionizing radiation.
The characteristic of sources of ionizing radiation is activity[BUT].
Activity is the number of units formed by the radiation source per unit time. (Measured in Bq - Becquerel and Curie).
1 Bq is the activity of the source in which 1 decay occurs in 1 second.
1 Curie - the activity of the source in which 37 billion decays occur in 1 second.
Specific activity is the activity of 1 kilogram (mass unit) of the source, i.e. the ratio of activity to mass. (Bq/kg).
Volume activity is the ratio of activity to source volume. (Bq/m 3)
surface activity is the ratio of source activity to its area. (Bq/m 2)
The law of radioactive decay determines the change in activity over time. A t = A 0 e - λt
Wigner Wey's law– during explosions and accidents, the activity of the source changes according to the exponential law. A t \u003d A 0 (t / t 0) - n
Characteristics of the interaction of ionizing radiation with the environment. (Dose characteristics)
To characterize the impact of ionizing radiation, the concept " dose measurement».
Depending on the task, different doses are used. If it is necessary to determine the amount of electricity created by ionizing radiation, then the exposure dose is used.
Exposure dose is the amount of electricity created by ionizing radiation per unit mass of a substance. The dose is measured in roentgens. [x-ray]
Absorbed dose- the amount of energy absorbed by a unit mass of a substance during the passage of radiation through it.
Dose equivalent is the dose equivalent to gamma radiation. . In the SI system, the equivalent dose is measured in sieverts, and the off-system unit is rem.
Effective dose.
With uniform irradiation, the effective dose is equal to the equivalent dose. When irradiating the whole person, an effective dose is used.
The dose is an integral indicator. Dose rate is used as a differential indicator. 
Dose rate characterizes the field of ionizing radiation. The dose rate was found to be directly proportional to the activity and inversely proportional to the square of the resistance. 
Any screen attenuates ionizing radiation exponentially.
Exposure of a person in everyday conditions
The OPA is composed of household and background radiation.
Background exposure consists of a natural radioactive background (background of the Earth and space) and a man-made radioactive field (background from nuclear explosions and nuclear energy).
Household exposure consists of medical exposure and exposure to electronic equipment.
ERF - the background of the Earth and space.
TIRF - background from nuclear explosions and energy 
Each person receives an average of 3 mSv/year.
Exposure limitation requirements
Federal Law No. 3 on radiation safety population
Radiation safety standard NORB 99/2009
Basic codes of practice on radiation safety 99 (OSPORB-99)
Group A personnel (20 mSv/year)
Group B personnel (5 mSv/year)
All population (1 mSv/year)
Building materials - granite, radon, radiation devices.
Section 3 (BJD technique)
electrical safety
Technical means of ensuring electrical safety
Means of ensuring electrical safety.
electrical safety- this is a system of organizational and technical measures and means that provide protection from harmful and dangerous factors: (often asked during the exam)
Electricity
Electric arc
electromagnetic radiation
Static electricity
The impact of electric current on a person
From the impact of current, injuries occur, which are called electrical injuries.
Electrical injuries can be:
electrical burns
electrical signs
Leather plating
Electric shock (divided into 5 degrees)
Local (i.e. hit at the point of contact with the current) are usually at high frequencies.
General (the whole body is affected).
1 degree (the occurrence of convulsions)
Grade 2 (appearance and cramps and pain)
Grade 3 (convulsions and loss of consciousness)
Grade 4 (loss of consciousness + or cessation of breathing or cessation of heartbeat)
Grade 5 (clinical death) cessation of breathing, heartbeat.
electric shock
Factors that determine the outcome of electric shock
Ohm's law- the current through a person is proportional to the voltage and inversely proportional to the resistance.
Factors of electric shock.
1 factor. Current I (for 50 Hz)
There are three criteria:
Threshold current (approximately 1 mA).
Threshold not releasing (approximately 10 mA)
Threshold fibrillation (lethal) approximately 100 mA.
2nd factor. Touch voltage. A voltage of 20 V is considered acceptable.
Touch voltage- this is the voltage between two points of the electrical network, which a person has touched.
3 factor. resistance of the human body.
In the normal mode of operation of electrical installations, the resistance of the human body takes 6.7 kOhm. In an emergency condition, the equipment resistance is reduced to 1 kOhm. If the temperature is above 35 degrees and the humidity is above 75%, the resistance decreases by another 3 times.
4th factor. The duration of the impact of electric current on a person.
Human Cardiocycle Determines Additional Exposure Time electric current. (t=0.2 - 1 sec)
5th factor. The path of current through the human body.
The most dangerous current paths through a person are hand - hand, hand - legs (because they pass through the human body).
6 factor Type of current.
The most dangerous variable. Less dangerous standing and upright.
7 factor Current frequency.
The most dangerous current with a frequency of 20 to 100 Hz. The higher the frequency of the current, the lower the chance of electric shock and the higher the chance of electric burn.
8 factor. Contact at acupuncture points.
9 factor. Attention. Electric current is in the human blood. The more attention, the more current. It mitigates the effects.
10 factor. Individual properties of a person.
11 factor. Switching scheme.
The most dangerous is two-phase touch (most likely death).
Single-phase contact in a network with isolated neutral. (less dangerous than the previous one)
Single-phase contact in networks with grounded neutral (dangerous). Especially when a person with bare feet.
12 factor. Conditions of the external environment.
According to the environmental conditions, all premises are divided into 4 classes:
Premises without increased danger
High risk area
Premises especially dangerous
Premises with especially adverse conditions.
The danger is determined by: temperature (35 degrees limit), humidity (75% limit), electrical conductivity of the floors, the presence of dust in the air, the presence of grounded equipment.
Classification of electrical networks
All electrical networks can be divided into 2 large groups:
Networks with voltage up to 1000 V
Networks with voltage over 1000 V
In addition, electrical networks are divided depending on the grounding of the neutral:
with earthed neutral
With isolated neutral
Depending on the number of wires:
Three-wire
Four-wire
five wire
The most common are four-wire networks with a grounded neutral. These networks are called TNCs. 
1 letter T terra (indicates that electrical conductors are grounded)
2 letter N. Indicates that the electrical installation is closed to the neutral wire.
3 letter C. Shows that zero protective and zero grounded are included in one wire.
Currently, five-wire networks have become the most widely used. In these networks, the neutral wire is working and the neutral wire is disconnected. Designated TN-S. 
For portable electrical equipment, a three-wire network with an isolated neutral is used. Designated IT. The scheme is effective if it is short, well maintained, and located in a dry room.
Technical ways to ensure electrical safety
Electrical safety includes the following elements:
Electrical isolation (at least 500 kΩ)
Zeroing
grounding
Safety shutdown
Electrical separation of networks
Application of low voltages
Fencing of current-carrying parts
The use of alarms, blocking, as well as safety signs and posters.
Technical security measures
Personal protective equipment
Organizational events
Regulations
Zeroing(Basic diagram of zeroing)
Zeroing- this is the connection of the housing to a grounded neutral wire.
Operating principle: Turns a ground fault into a short circuit.
Application area: Three-phase four-wire networks with a solidly grounded neutral
Protective earth
Protective earth– deliberate connection of the housing to the ground.
Operating principle: reduction to a safe value of the current through a person.
Application area: three-phase three-wire networks with isolated neutral (for networks up to 1000 V).
Electrical protective equipment (called personal protective equipment PPE)
Basic. Allows you to work under pressure. (Dielectric gloves, insulating pliers and voltage gauges)
Additional. (dielectric galoshes, insulating pads, rugs)
Portable means, including temporary portable fences and insulating pads.
Portable shielding equipment
Means isolating
Enclosing means
Shielding means
Safety means
These are means that protect against damaging factors of a non-electrical nature that occur when working with electrical equipment. (glasses, shields, safety belts, gas masks, non-flammable gloves).
Organizational bases of electrical safety
Above, we considered the technical basis of safety, but as the analysis of accidents shows, many people die due to poor organization of electrical safety.
The main organizational activities include:
work and rest
Transition to other jobs
Completion of works
Registration of work on electrical installations should be carried out: according to orders or orders. If the work is carried out for more than 1 hour or more than three people participate in them, then an order for these works must be issued. If the work is less than an hour and less than three people, then the order.
People who spend electrical work are required to have a work permit. To do this, they are assigned a classification. There are only 5 groups.
Work Supervision
Compliance with the regime
First aid for electric shock
First aid should be available within 1 minute.
Necessary: establish the presence of breathing, pulse, shock; organize an ambulance call; carry out resuscitation measures: restore breathing, chest compressions.
FEDERAL AGENCY FOR EDUCATION OF THE RUSSIAN FEDERATION
Impact on the body of non-ionizing radiation
Kursk, 2010
Introduction
2. Influence on the nervous system
5. Effect on sexual function
7. Combined effect of EMF and other factors
8. Diseases caused by exposure to non-ionizing radiation
9. Main sources of EMF
10. Biological effect of non-ionizing radiation
11. Microwaves and RF radiation
12. Engineering and technical measures to protect the population from EMF
13. Therapeutic and preventive measures
Conclusion
List of used literature
Introduction
It is known that radiation can harm human health and that the nature of the observed effects depends on the type of radiation and on the dose. The impact of radiation on health depends on the wavelength. The consequences that are most often meant when talking about the effects of irradiation (radiation injury and various forms cancer) are caused only by shorter wavelengths. These types of radiation are known as ionizing radiation. In contrast, the longer wavelengths - from the near ultraviolet (UV) to radio waves and beyond - are called non-ionizing radiation, their impact on health is completely different. IN modern world we are surrounded by a huge number of sources of electromagnetic fields and radiation. In hygienic practice, non-ionizing radiation also includes electric and magnetic fields. Radiation will be non-ionizing if it is not capable of breaking the chemical bonds of molecules, that is, it is not capable of forming positively and negatively charged ions.
So, non-ionizing radiation includes: electromagnetic radiation (EMR) of the radio frequency range, constant and variable magnetic fields (PMF and PMF), electromagnetic fields of industrial frequency (EMFFC), electrostatic fields (ESP), laser radiation (LI).
Often, the action of non-ionizing radiation is accompanied by other production factors that contribute to the development of the disease (noise, high temperature, chemicals, emotional and mental stress, light flashes, visual strain). Since the main carrier of non-ionizing radiation is EMR, most of the abstract is devoted to this particular type of radiation.
1. Consequences of exposure to radiation for human health
In the overwhelming majority of cases, exposure occurs with fields of relatively low levels, the consequences listed below apply to such cases.
Numerous studies in the field of the biological action of EMF will make it possible to determine the most sensitive systems of the human body: nervous, immune, endocrine and reproductive. These body systems are critical. The reactions of these systems must necessarily be taken into account when assessing the risk of EMF exposure to the population.
The biological effect of EMF accumulates under conditions of long-term long-term exposure, as a result, the development of long-term consequences is possible, including degenerative processes of the central nervous system, blood cancer (leukemia), brain tumors, hormonal diseases. EMF can be especially dangerous for children, pregnant women, people with diseases of the central nervous, hormonal, cardiovascular system, allergy sufferers, people with weakened immune systems.
2. Influence on the nervous system
A large number of studies carried out in Russia, and monographic generalizations made, give reason to classify the nervous system as one of the most sensitive systems in the human body to the effects of EMF. At the level of a nerve cell, structural formations for the transmission of nerve impulses (synapse), at the level of isolated nerve structures, significant deviations occur when exposed to low-intensity EMF. Changes in higher nervous activity, memory in people who have contact with EMF. These individuals may be prone to developing stress responses. Certain structures of the brain have an increased sensitivity to EMF. The nervous system of the embryo exhibits a particularly high sensitivity to EMF.
3. Effect on the immune system
At present, enough data has been accumulated indicating the negative effect of EMF on the immunological reactivity of the body. Research results Russian scientists give reason to believe that under the influence of EMF, the processes of immunogenesis are disturbed, more often in the direction of their suppression. It has also been established that in animals irradiated with EMF, the nature of the infectious process changes - the course of the infectious process is aggravated. The effect of high-intensity EMF on the body's immune system is manifested in a depressing effect on the T-system of cellular immunity. EmFs can contribute to nonspecific inhibition of immunogenesis, enhance the formation of antibodies to fetal tissues and stimulate an autoimmune reaction in the body of a pregnant female.
4. Influence on the endocrine system and neurohumoral response
In the works of Russian scientists back in the 60s, in the interpretation of the mechanism of functional disorders under the influence of EMF, the leading place was given to changes in the pituitary-adrenal system. Studies have shown that under the action of EMF, as a rule, stimulation of the pituitary-adrenal system occurred, which was accompanied by an increase in the content of adrenaline in the blood, activation of blood coagulation processes. It was recognized that one of the systems that early and naturally involves the body's response to the impact of various environmental factors is the hypothalamus-pituitary-adrenal cortex system. The research results confirmed this position.
5. Effect on sexual function
Sexual dysfunctions are usually associated with changes in its regulation by the nervous and neuroendocrine systems. Repeated exposure to EMF causes a decrease in the activity of the pituitary gland
Any environmental factor that affects the female body during pregnancy and affects embryonic development is considered teratogenic. Many scientists attribute EMF to this group of factors. It is generally accepted that EMF can, for example, cause deformities, affecting various stages of pregnancy. Although there are periods of maximum sensitivity to EMF. The most vulnerable periods are usually the early stages of embryonic development, corresponding to the periods of implantation and early organogenesis.
An opinion was expressed about the possibility of a specific effect of EMF on the sexual function of women, on the embryo. A higher sensitivity to the effects of EMF was noted in the ovaries than in the testes.
It has been established that the sensitivity of the embryo to EMF is much higher than the sensitivity of the maternal organism, and intrauterine damage to the fetus by EMF can occur at any stage of its development. The results of the conducted epidemiological studies will allow us to conclude that the presence of women's contact with electromagnetic radiation can lead to premature birth, affect the development of the fetus and, finally, increase the risk of congenital malformations.
6. Other biomedical effects
Since the beginning of the 1960s, extensive studies have been carried out in the USSR to study the health of people who have contact with EMF at work. The results of clinical studies have shown that prolonged contact with EMF in the microwave range can lead to the development of diseases, the clinical picture of which is determined primarily by changes in the functional state of the nervous and cardiovascular systems. It was proposed to isolate an independent disease - radio wave disease. This disease, according to the authors, can have three syndromes as the severity of the disease increases:
asthenic syndrome;
astheno-vegetative syndrome;
hypothalamic syndrome.
The earliest clinical manifestations of the effects of EM radiation on humans are functional disorders of the nervous system, manifested primarily in the form of vegetative dysfunctions of neurasthenic and asthenic syndrome. Persons who have been in the zone of EM radiation for a long time complain of weakness, irritability, fatigue, memory loss, and sleep disturbance. Often these symptoms are accompanied by disorders of autonomic functions. Disorders of the cardiovascular system are usually manifested by neurocirculatory dystonia: lability of the pulse and blood pressure, a tendency to hypotension, pain in the heart area, etc. Phase changes in the composition of peripheral blood (lability of indicators) are also noted, followed by the development of moderate leukopenia, neuropenia , erythrocytopenia. Changes in the bone marrow are in the nature of a reactive compensatory tension of regeneration. Typically, these changes occur in people who, by the nature of their work, were constantly exposed to EM radiation with a sufficiently high intensity. Those working with MF and EMF, as well as the population living in the EMF area, complain of irritability and impatience. After 1-3 years, some have a feeling of internal tension, fussiness. Attention and memory are impaired. There are complaints of low efficiency of sleep and fatigue.
Considering the important role of the cerebral cortex and hypothalamus in the implementation of human mental functions, it can be expected that prolonged repeated exposure to maximum permissible EM radiation (especially in the decimeter wavelength range) can lead to mental disorders.
6. Combined effect of EMF and other factors
The available results indicate a possible modification of the EMF bioeffects of both thermal and nonthermal intensity under the influence of a number of factors of both physical and chemical nature. The conditions of the combined action of EMF and other factors made it possible to reveal a significant effect of EMF of ultra-low intensities on the reaction of the organism, and in some combinations a pronounced pathological reaction may develop.
7. Diseases caused by exposure to non-ionizing radiation
Acute exposure occurs in exceptionally rare cases of gross violation of the safety regulations of streets serving powerful generators or laser installations. Intense EMR is the first to cause a thermal effect. Patients complain of malaise, pain in the limbs, muscle weakness, fever, headache, redness of the face, sweating, thirst, impaired cardiac activity. Diencephalic disorders can be observed in the form of attacks of tachycardia, trembling, paroxysmal headache, vomiting.
With acute exposure to laser radiation, the degree of damage to the eyes and skin (critical organs) depends on the intensity and spectrum of the radiation. The laser beam can cause clouding of the cornea, burns of the iris, lens, followed by the development of cataracts. A retinal burn leads to the formation of a scar, which is accompanied by a decrease in visual acuity. The listed lesions of the eyes by laser radiation do not have specific features.
Skin lesions with a laser beam depend on the radiation parameters and are of the most diverse nature; from functional changes in the activity of intradermal enzymes or mild erythema at the site of exposure to burns resembling electrocoagulation burns with electric shock, or rupture of the skin.
In the conditions of modern production, occupational diseases caused by exposure to non-ionizing radiation are chronic.
The leading place in the clinical picture of the disease is occupied by functional changes in the central nervous system, especially its autonomic parts, and the cardiovascular system. There are three main syndromes: asthenic, asthenovegetative (or hypertonic-type neurocirculatory dystonia syndrome) and hypothalamic.
Patients complain of headache, fatigue, general weakness, irritability, irascibility, decreased performance, sleep disturbance, pain in the heart area. Arterial hypotension and bradycardia are characteristic. In more pronounced cases, vegetative disorders associated with increased excitability of the sympathetic division of the autonomic nervous system and manifested by vascular instability with hypertensive angiospastic reactions (blood pressure instability, pulse lability, bradycardia and tachycardia, general and local hyperhidrosis) are added. Perhaps the formation of various phobias, hypochondriacal reactions. In some cases, a hypothalamic (diencephalic) syndrome develops, characterized by the so-called sympathetic-adrenal crises.
Clinically, there is an increase in tendon and periosteal reflexes, tremor of the fingers, a positive symptom of Romberg, oppression or increased dermographism, distal hypesthesia, acrocyanosis, and a decrease in skin temperature. Under the action of PMF, polyneuritis can develop, under the influence of microwave electromagnetic fields - cataracts.
Changes in peripheral blood are nonspecific. There is a tendency to cytopenia, sometimes moderate leukocytosis, lymphocytosis, reduced ESR. There may be an increase in hemoglobin, erythrocytosis, reticulocytosis, leukocytosis (EPCH and ESP); decrease in hemoglobin (with laser radiation).
Diagnosis of lesions from chronic exposure to non-ionizing radiation is difficult. It should be based on a detailed study of working conditions, analysis of the dynamics of the process, a comprehensive examination of the patient.
Skin changes caused by chronic exposure to non-ionizing radiation:
Actinic (photochemical) keratosis
actinic reticuloid
Rhombic skin on the back of the head (neck)
Poikiloderma Civatta
Senile atrophy (flaccidity) of the skin
Actinic [photochemical] granuloma
8. Main sources of EMF
Household electrical appliances
All household appliances that operate using electric current are sources of electromagnetic fields.
The most powerful should be recognized as microwave ovens, convection ovens, refrigerators with a “frost-free” system, kitchen hoods, electric stoves, TVs. The actual EMF generated, depending on the specific model and mode of operation, can vary greatly among equipment of the same type. All data below refer to a magnetic field of a power frequency of 50 Hz.
The values of the magnetic field are closely related to the power of the device - the higher it is, the higher the magnetic field during its operation. The values of the electric field of industrial frequency of almost all household appliances do not exceed several tens of V/m at a distance of 0.5 m, which is much less than the MPD of 500 V/m.
Table 1 presents data on the distance at which a magnetic field of industrial frequency (50 Hz) of 0.2 μT is fixed during the operation of a number of household appliances.
Table 1. Propagation of the magnetic field of industrial frequency from household electrical appliances(above 0.2 µT)
| A source | Distance at which a value greater than 0.2 μT is fixed |
| Refrigerator equipped with "No frost" system (when the compressor is running) | 1.2 m from the door; 1.4 m from back wall |
| Refrigerator normal (when the compressor is running) | 0.1 m from motor |
| Iron (heating mode) | 0.25 m from handle |
| TV 14" | 1.1 m from the screen; 1.2 m from the side wall. |
| electric radiator | 0.3 m |
| Floor lamp with two lamps of 75 W | 0.03 m (from wire) |
| Electric oven air grill | 0.4 m from the front wall 1.4 m from the side wall |
Rice. 1. Biological effect of non-ionizing radiation
Non-ionizing radiation can enhance the thermal motion of molecules in living tissue. This leads to an increase in tissue temperature and can cause harmful effects such as burns and cataracts, as well as fetal abnormalities. The possibility of destruction of complex biological structures, such as cell membranes, is also not ruled out. For the normal functioning of such structures, an ordered arrangement of molecules is necessary. Thus, the consequences are more profound than a simple increase in temperature, although experimental evidence for this is still insufficient.
Most of the experimental data on non-ionizing radiation relates to the radio frequency range. These data show that doses above 100 milliwatts (mW) per cm2 cause direct thermal damage as well as the development of cataracts in the eye. At doses between 10 and 100 mW/cm2, changes due to thermal stress were observed, including congenital anomalies in descendants. At 1-10 mW/cm2, changes were noted in the immune system and the blood-brain barrier. In the range from 100 µW/cm2 to 1 mW/cm2, almost no effects have been reliably established.
When exposed to non-ionizing radiation, only immediate effects, such as tissue overheating, appear to be significant (although there is new, as yet incomplete, evidence that workers exposed to microwaves and people living very close to high-voltage power lines may be more susceptible to cancer).
9. Microwaves and RF radiation
No visible consequences low levels Microwave exposure must be contrasted with the fact that the growth in microwave use is at least 15% per year. In addition to being used in microwave ovens they are used in radar and, as a means of transmitting signals, in television and in telephone and telegraph communications. In the former Soviet Union, a limit of 1 µW/cm2 was adopted for the population.
Industrial workers involved in the heating, drying, and laminate manufacturing processes may be at some risk, as are professionals working in broadcast, radar, and relay towers, or some members of the military. Workers filed compensation claims alleging microwaves contributed to disability, and in at least one case the decision was made in favor of the worker.
With the increase in the number of sources of microwave radiation, there is increasing concern about its impact on the population.
When purchasing household appliances, check in the Hygienic Conclusion (Certificate) a mark on the compliance of the product with the requirements of the "Interstate Sanitary Standards for Permissible Levels of Physical Factors When Using Consumer Goods in the Domestic Conditions", MSanPiN 001-96;
Use a technique with less power consumption: power frequency magnetic fields will be smaller, all other things being equal;
Potentially unfavorable sources of an industrial frequency magnetic field in an apartment include refrigerators with a “frost-free” system, some types of “warm floors”, heaters, TVs, some alarm systems, various chargers, rectifiers and current converters - the sleeping place should be at a distance at least 2 meters from these items if they work during your night's rest.
Means and methods of protection against EMF are divided into three groups: organizational, engineering and technical and treatment and prophylactic.
Organizational measures include preventing people from entering areas with high EMF intensity, creating sanitary protection zones around antenna structures for various purposes.
General principles, which form the basis of engineering and technical protection, are as follows: electrical sealing of circuit elements, blocks, units of the installation as a whole in order to reduce or eliminate electromagnetic radiation; protecting the workplace from radiation or removing it to a safe distance from the source of radiation. Used to shield the workplace different types screens: reflective and absorbing.
As personal protective equipment, special clothing made of metallized fabric and goggles are recommended.
Therapeutic and preventive measures should be aimed primarily at the early detection of violations in the state of health of workers. For this purpose, preliminary and periodic medical examinations of persons working under microwave exposure are provided - 1 time in 12 months, UHF and HF range - 1 time in 24 months.
10. Engineering and technical measures to protect the population from EMF
Engineering and technical protective measures are based on the use of the phenomenon of shielding of electromagnetic fields directly in the places where a person is located or on measures to limit the emission parameters of the field source. The latter, as a rule, is used at the stage of development of a product that serves as a source of EMF.
One of the main ways to protect against electromagnetic fields is their shielding in places where a person stays. Two types of shielding are generally implied: shielding of EMF sources from people and shielding of people from EMF sources. The protective properties of screens are based on the effect of weakening the intensity and distortion of the electric field in space near a grounded metal object.
From the electric field of industrial frequency, created by power transmission systems, is carried out by establishing sanitary protection zones for power lines and reducing the field strength in residential buildings and in places where people can stay for a long time by using protective screens. Protection from a power frequency magnetic field is practically possible only at the stage of product development or object design, as a rule, a decrease in the field level is achieved through vector compensation, since other methods of shielding a power frequency magnetic field are extremely complex and expensive.
The main requirements for ensuring the safety of the population from an electric field of industrial frequency created by power transmission and distribution systems are set out in the Sanitary Norms and Rules "Protection of the population from the effects of an electric field created by overhead power lines of alternating current of industrial frequency" No. 2971-84. For details on protection requirements, see the section "Sources of EMF. PTL"
When shielding EMF in the radio frequency ranges, a variety of radio-reflective and radio-absorbing materials are used.
Radio-reflective materials include various metals. The most commonly used iron, steel, copper, brass, aluminum. These materials are used in the form of sheets, mesh, or in the form of gratings and metal tubes. The shielding properties of sheet metal are higher than meshes, while the mesh is structurally more convenient, especially when shielding viewing and ventilation openings, windows, doors, etc. The protective properties of the grid depend on the size of the cell and the thickness of the wire: the smaller the size of the cells, the thicker the wire, the higher its protective properties. A negative property of reflective materials is that in some cases they create reflected radio waves, which can increase human exposure.
More convenient materials for shielding are radio absorbing materials. Sheets of absorbent materials may be single or multi-layered. Multilayer - provide absorption of radio waves in a wider range. To improve the shielding effect, many types of radio-absorbing materials have a metal mesh or brass foil pressed on one side. When creating screens, this side is turned in the direction opposite to the radiation source.
Despite the fact that absorbing materials are in many respects more reliable than reflective ones, their use is limited by high cost and narrow absorption spectrum.
In some cases, the walls are covered with special paints. Colloidal silver, copper, graphite, aluminum, powdered gold are used as conductive pigments in these paints. Ordinary oil paint has a fairly high reflectivity (up to 30%), lime coating is much better in this respect.
Radio emissions can penetrate into rooms where people are located through window and door openings. For shielding viewing windows, windows of rooms, glazing of ceiling lights, partitions, metallized glass is used, which has shielding properties. This property is given to glass by a thin transparent film of either metal oxides, most often tin, or metals - copper, nickel, silver, and combinations thereof. The film has sufficient optical transparency and chemical resistance. Being deposited on one side of the glass surface, it attenuates the radiation intensity in the range of 0.8 - 150 cm by 30 dB (1000 times). When the film is applied to both glass surfaces, the attenuation reaches 40 dB (by a factor of 10,000).
To protect the population from exposure to electromagnetic radiation in building structures, a metal mesh, metal sheet or any other conductive coating, including specially designed ones, can be used as protective screens. Construction Materials. In some cases, it is sufficient to use a grounded metal mesh placed under the facing or plaster layer.
Various films and fabrics with a metallized coating can also be used as screens.
Almost all building materials have radio shielding properties. As an additional organizational and technical measure to protect the population, when planning construction, it is necessary to use the property of "radio shadow" arising from the terrain and enveloping local objects by radio waves.
In recent years, metallized fabrics based on synthetic fibers have been obtained as radio shielding materials. They are obtained by chemical metallization (from solutions) of tissues of various structures and densities. Existing production methods allow you to adjust the amount of deposited metal in the range from hundredths to units of microns and change the surface resistivity of tissues from tens to fractions of an ohm. Shielding textile materials have a small thickness, lightness, flexibility; they can be duplicated with other materials (fabrics, leather, films), they are well combined with resins and latexes.
11. Therapeutic and preventive measures
Sanitary and preventive maintenance includes the following activities:
organizing and monitoring the implementation of hygienic standards, operating modes of personnel servicing EMF sources;
identification of occupational diseases caused by adverse environmental factors;
development of measures to improve the working and living conditions of personnel, to increase the resistance of the body of workers to the effects adverse factors environment.
The current hygienic control is carried out depending on the parameters and mode of operation of the radiant installation, but as a rule, at least once a year. At the same time, the characteristics of EMF are determined in industrial premises, in residential and public buildings and in open areas. EMF intensity measurements are also carried out when changes are made to the conditions and modes of operation of EMF sources that affect radiation levels (replacement of generator and radiating elements, change technological process, changing shielding and protective equipment, increasing power, changing the location of radiating elements, etc.).
In order to prevent, early diagnose and treat health problems, employees associated with EMF exposure must undergo preliminary medical examinations upon admission to work and periodic medical examinations in the manner prescribed by the relevant order of the Ministry of Health.
All persons with initial manifestations of clinical disorders caused by exposure to EMF (asthenic astheno-vegetative, hypothalamic syndrome), as well as with general diseases, the course of which can be aggravated under the influence of adverse factors in the working environment (organic diseases of the central nervous system, hypertension, diseases of the endocrine system , blood diseases, etc.), should be taken under supervision with appropriate hygienic and therapeutic measures aimed at improving working conditions and restoring the health of workers.
Conclusion
Currently, an active study is underway of the mechanisms of the biological action of physical factors of non-ionizing radiation: acoustic waves and electromagnetic radiation on biological systems of different levels of organization; enzymes, cells surviving brain sections of laboratory animals, behavioral reactions of animals and the development of reactions in chains: primary targets - cell - cell populations - tissues.
Evaluation research is developing environmental impact impact on natural and agrarian cenoses of technogenic stressors - microwave and UV-B radiation, the main tasks of which are:
study of the consequences of the depletion of the ozone layer on the components of the agrocenoses of the non-chernozem zone of Russia;
study of the mechanisms of action of UV-B radiation on plants;
study of the separate and combined effects of electromagnetic radiation of various ranges (microwave, gamma, UV, IR) on farm animals and model objects in order to develop methods for hygienic and environmental regulation of electromagnetic environmental pollution;
development of environmentally friendly technologies based on the use of physical factors for various sectors of the AMS (plant growing, animal husbandry, food and processing industry in order to intensify agricultural production.
When interpreting the results of studies of the biological effect of non-ionizing radiation (electromagnetic and ultrasonic), the central and still little studied questions remain questions about molecular mechanism, primary target, and radiation action thresholds. One of the most important consequences is that relatively small changes in local temperature in the nervous tissue (from tenths to several degrees) can lead to a noticeable change in the speed of synaptic transmission up to the complete shutdown of the synapse. Such temperature changes can be caused by radiations of therapeutic intensity. From these prerequisites follows the hypothesis of the existence of a general mechanism of action of non-ionizing radiation - a mechanism based on a slight local heating of parts of the nervous tissue.
Thus, such a complex and little-studied aspect as non-ionizing radiation and their impact on the environment remains to be studied in the future.
List of used literature:
1. http://www.botanist.ru/
2. Active detection of malignant neoplasms of the skin Denisov L.E., Kurdina M.I., Potekaev N.S., Volodin V.D.
3. DNA instability and long-term effects of exposure to radiation.
The future of the nation depends. In the affected territories of Ukraine, where the density of radioactive contamination by 137Cs ranged from 5 to 40 Ku / km2, conditions arose for long-term exposure to low doses of ionizing radiation, the effect of which on the body of a pregnant woman and fetus was not actually studied before the Chernobyl disaster. From the first days of the accident, careful monitoring of the state of health was carried out ...
Or power flux density - S, W/m2. Abroad, PES is usually measured for frequencies above 1 GHz. PES characterizes the amount of energy lost by the system per unit time due to the radiation of electromagnetic waves. 2. Natural sources of EMF Natural sources of EMF are divided into 2 groups. The first is the Earth's field: a permanent magnetic field. Processes in the magnetosphere cause fluctuations in the geomagnetic ...
Biophysicists were offered a set of organizational, technical, sanitary and hygienic and ergonomic requirements /36/, which are a significant addition to the methodological recommendations /19/. In accordance with GOST 12.1.06-76 Electromagnetic fields of radio frequencies. Permissible levels and control requirements for microwave radiation standard value of energy load: ENPDU=2Wh/m2 (200mkWh/cm2 ...
Endocrine and sexual. These body systems are critical. The reactions of these systems must necessarily be taken into account when assessing the risk of EMF exposure to the population. The influence of the electromagnetic field on the nervous system. A large number of studies and monographic generalizations made make it possible to classify the nervous system as one of the most sensitive systems to the effects of electromagnetic fields...
Department of BJD
Test
discipline: Life safety
on the topic: Ionizing radiation
Perm, 2004
Introduction
Ionizing radiation is called radiation, the interaction of which with the environment leads to the formation of electric charges of various signs.
Ionizing radiation is the radiation that radioactive substances possess.
Under the influence of ionizing radiation, a person develops radiation sickness.
The main goal of radiation safety is to protect the health of the population, including personnel, from the harmful effects of ionizing radiation by observing the basic principles and norms of radiation safety without unreasonable restrictions on useful activities when using radiation in various areas of the economy, in science and medicine.
Radiation safety standards (NRB-2000) are used to ensure human safety under the influence of ionizing radiation of artificial or natural origin.
Main characteristics of ionizing radiation
Ionizing radiation is called radiation, the interaction of which with the environment leads to the formation of electric charges of various signs. The sources of these radiations are widely used in engineering, chemistry, medicine, agriculture and other areas, for example, in measuring soil density, detecting leaks in gas pipelines, measuring the thickness of sheets, pipes and rods, antistatic treatment of fabrics, polymerization of plastics, radiation therapy of malignant tumors, etc. However, it should be remembered that sources of ionizing radiation pose a significant threat to the health and life of people using them.
There are 2 types of ionizing radiation:
corpuscular, consisting of particles with a rest mass other than zero (alpha and beta radiation and neutron radiation);
electromagnetic (gamma radiation and x-rays) with a very short wavelength.
alpha radiation is a stream of helium nuclei with high speed. These nuclei have a mass of 4 and a charge of +2. They are formed during the radioactive decay of nuclei or during nuclear reactions. Currently, more than 120 artificial and natural alpha-radioactive nuclei are known, which, emitting an alpha particle, lose 2 protons and 2 neurons.
The energy of alpha particles does not exceed a few MeV (mega-electron-volt). The emitted alpha particles move almost in a straight line at a speed of about 20,000 km/s.
Under the path length of a particle in air or other media, it is customary to call the greatest distance from the radiation source at which it is still possible to detect a particle before it is absorbed by a substance. The path length of a particle depends on the charge, mass, initial energy, and the medium in which the motion occurs. With an increase in the initial energy of the particle and a decrease in the density of the medium, the path length increases. If the initial energy of the emitted particles is the same, then heavy particles have lower velocities than light ones. If the particles move slowly, then their interaction with the atoms of the substance of the medium is more efficient and the particles quickly waste their energy reserve.
The path length of alpha particles in air is usually less than 10 cm. Due to their large mass, alpha particles quickly lose their energy when interacting with matter. This explains their low penetrating power and high specific ionization: when moving in air environment alpha particle for 1 cm of its path forms several tens of thousands of pairs of charged particles - ions.
beta radiation is a stream of electrons or positrons resulting from radioactive decay. About 900 beta radioactive isotopes are currently known.
The mass of beta particles is several tens of thousands of times less than the mass of alpha particles. Depending on the nature of the source of beta radiation, the speed of these particles can lie within 0.3 - 0.99 of the speed of light. The energy of beta particles does not exceed several MeV, the path length in air is approximately 1800 cm, and in the soft tissues of the human body ~ 2.5 cm. The penetrating power of beta particles is higher than that of alpha particles (due to their smaller mass and charge).
neutron radiation is a stream of nuclear particles that do not have an electric charge. The mass of a neutron is approximately 4 times less than the mass of alpha particles. Depending on the energy, slow neutrons are distinguished (with an energy of less than 1 KeV (kilo-electron-Volt) \u003d 10 3 eV), neutrons of intermediate energies (from 1 to 500 KeV) and fast neutrons (from 500 KeV to 20 MeV). During the inelastic interaction of neutrons with the nuclei of atoms of the medium, secondary radiation arises, consisting of charged particles and gamma quanta (gamma radiation). During elastic interactions of neutrons with nuclei, the usual ionization of matter can be observed. The penetrating power of neutrons depends on their energy, but it is much higher than that of alpha or beta particles. Neutron radiation has a high penetrating power and represents the greatest danger to humans of all types of corpuscular radiation. The neutron flux power is measured by the neutron flux density.
Gamma radiation It is electromagnetic radiation with high energy and short wavelength. It is emitted during nuclear transformations or the interaction of particles. High energy (0.01 - 3 MeV) and short wavelength determines the high penetrating power of gamma radiation. Gamma rays are not deflected in electric and magnetic fields. This radiation has a lower ionizing power than alpha and beta radiation.
x-ray radiation can be obtained in special X-ray tubes, in electron accelerators, in the environment surrounding the source of beta radiation, etc. X-ray radiation is one of the types of electromagnetic radiation. Its energy usually does not exceed 1 MeV. X-ray radiation, like gamma radiation, has a low ionizing ability and a large penetration depth.
To characterize the effect of ionizing radiation on a substance, the concept of radiation dose has been introduced. The dose of radiation is the part of the energy transferred by radiation to the substance and absorbed by it. The quantitative characteristic of the interaction of ionizing radiation and matter is absorbed radiation dose(E), equal to the ratio of the average energy dE transferred by ionizing radiation to a substance in an elementary volume, to the mass of the irradiated substance in this volume dm:
Until recently, only X-ray and gamma radiation, based on their ionizing effect, was taken as a quantitative characteristic. exposure dose X is the ratio of the total electric charge dQ of ions of the same sign, arising in a small volume of dry air, to the mass of air dm in this volume, i.e.
To assess the possible damage to health during chronic exposure to ionizing radiation of arbitrary composition, the concept equivalent dose(H). This value is defined as the product of the absorbed dose D and the average radiation quality factor Q (dimensionless) at a given point in the tissue of the human body, i.e.:
There is another characteristic of ionizing radiation - dose rate X (respectively absorbed, exposure or equivalent) representing the dose increment over a small period of time dx divided by this period dt. Thus, the exposure dose rate (x or w, C / kg s) will be:
X \u003d W \u003d dx / dt
The biological effect of the considered radiations on the human body is different.
Alpha particles, passing through matter and colliding with atoms, ionize (charge) them, knocking out electrons. In rare cases, these particles are absorbed by the nuclei of atoms, transferring them to a state of higher energy. This excess energy contributes to the flow of various chemical reactions that do not proceed without irradiation or proceed very slowly. Alpha radiation has a strong effect on the organic substances that make up the human body (fats, proteins and carbohydrates). On the mucous membranes, this radiation causes burns and other inflammatory processes.
Under the action of beta radiation, radiolysis (decomposition) of water contained in biological tissues occurs, with the formation of hydrogen, oxygen, hydrogen peroxide H 2 O 2, charged particles (ions) OH - and HO - 2. The decomposition products of water have oxidizing properties and cause the destruction of many organic substances that make up the tissues of the human body.
The action of gamma and X-ray radiation on biological tissues is mainly due to the free electrons formed. Neutrons passing through matter produce the strongest changes in it in comparison with other ionizing radiations.
Thus, the biological effect of ionizing radiation is reduced to a change in the structure or destruction of various organic substances (molecules) that make up the human body. This leads to a violation of the biochemical processes occurring in the cells, or even to their death, resulting in damage to the body as a whole.
Distinguish between external and internal irradiation of the body. External exposure is understood as the effect on the body of ionizing radiation from sources external to it. Internal exposure is carried out by radioactive substances that have entered the body through the respiratory organs, the gastrointestinal tract or through the skin. Sources of external radiation - cosmic rays, natural radioactive sources in the atmosphere, water, soil, food, etc., sources of alpha, beta, gamma, X-ray and neutron radiation used in engineering and medicine, charged particle accelerators, nuclear reactors (including accidents at nuclear reactors) and a number of others.
Radioactive substances that cause internal irradiation of the body enter it when eating, smoking, drinking contaminated water. The entry of radioactive substances into the human body through the skin occurs in rare cases (if the skin has damage or open wounds). Internal irradiation of the body lasts until the radioactive substance decays or is removed from the body as a result of physiological metabolic processes. Internal exposure is dangerous because it causes long-term non-healing ulcers of various organs and malignant tumors.
When working with radioactive substances, the hands of operators are exposed to significant radiation. Under the influence of ionizing radiation, a chronic or acute (radiation burn) damage to the skin of the hands develops. Chronic lesion is characterized by dry skin, cracking, ulceration and other symptoms. In acute lesions of the hands, edema, tissue necrosis, ulcers occur, at the site of formation of which the development of malignant tumors is possible.
Under the influence of ionizing radiation, a person develops radiation sickness. There are three degrees of it: the first (light), second and third (severe).
Symptoms of radiation sickness of the first degree are weakness, headaches, sleep disturbance and appetite, which increase in the second stage of the disease, but they are additionally accompanied by disturbances in the activity of the cardiovascular system, metabolism and blood composition change, and digestive organs are upset. At the third stage of the disease, hemorrhages are observed, hair loss, the activity of the central nervous system and sex glands is disrupted. In people who have undergone radiation sickness, the likelihood of developing malignant tumors and diseases of the hematopoietic organs increases. Radiation sickness in an acute (severe) form develops as a result of irradiation of the body with large doses of ionizing radiation in a short period of time. The impact on the human body and small doses of radiation is dangerous, since in this case a violation of the hereditary information of the human body can occur, mutations occur.
A low level of development of a mild form of radiation sickness occurs at an equivalent radiation dose of approximately 1 Sv, a severe form of radiation sickness, in which half of all exposed people die, occurs at an equivalent radiation dose of 4.5 Sv. A 100% lethal outcome from radiation sickness corresponds to an equivalent radiation dose of 5.5–7.0 Sv.
Currently, a number of chemical preparations (protectors) have been developed that significantly reduce the negative effect of ionizing radiation on the human body.
In Russia, the maximum permissible levels of ionizing radiation and the principles of radiation safety are regulated by the "Radiation Safety Standards" NRB-76, "Basic Sanitary Rules for Working with Radioactive Substances and Other Sources of Ionizing Radiation" OSP72-80. In accordance with these regulatory documents, exposure standards are established for the following three categories of persons:
For category A persons, the main dose limit is the individual equivalent dose of external and internal radiation per year (Sv / year) depending on the radiosensitivity of organs (critical organs). This is the maximum allowable dose (MAD) - the highest value of the individual equivalent dose per year, which, with uniform exposure for 50 years, will not cause adverse changes in the state of health of personnel detected by modern methods.
For category A personnel, the individual equivalent dose ( H, Sv) accumulated in the critical organ over time T(years) from the beginning of professional work, should not exceed the value determined by the formula:
H = SDA ∙ T. In addition, the dose accumulated by the age of 30 should not exceed 12 SDA.
For category B, a dose limit per year (PD, Sv/year) is set, which is understood as the highest average value of the individual equivalent dose per calendar year for a critical group of people, at which uniform exposure for 70 years cannot cause adverse changes in the state of health, detected by modern methods. Table 1 shows the main dose limits of external and internal exposures depending on the radiosensitivity of organs.
Table 1 - Basic values of dose limits for external and internal exposure
Ionizing (radioactive) radiation includes X-ray and γ-radiation, which are electromagnetic oscillations with a very short wavelength, as well as α- and β-radiation, positron and neutron radiation, which are a stream of particles with or without a charge. X-ray and γ-radiation are collectively referred to as photon radiation.
The main property of radioactive radiation is its ionizing effect. When they pass through the tissues, neutral atoms or molecules acquire a positive or negative charge and turn into ions. Alpha radiation, which is a positively charged helium nucleus, has a high ionizing ability (up to several tens of thousands of pairs of ions per 0.01 m of its path), but a small range: in air 0.02 ... 0.11 m, in biological tissues (2..,6)10-6 m. Beta radiation and positron radiation are, respectively, electron and positron flows with a much lower ionizing ability, which, at the same energy, is 1000 times less than that of β-particles. Neutron radiation has a very large penetrating power. Passing through tissues, neutrons - particles that do not have a charge, cause the formation of radioactive substances in them (induced activity). X-rays arising from β-radiation or in X-ray tubes, electron accelerators, etc., as well as γ-radiation emitted by radionuclides - the nuclei of radioactive elements, have the lowest ability to ionize the medium, but the highest penetrating ability. Their range in air is several hundred meters, and in materials used for protection against ionizing radiation (lead, concrete), tens of centimeters.
Exposure can be external, when the source of radiation is outside the body, and internal, arising from the ingestion of radioactive substances through the respiratory tract, gastrointestinal tract, or absorption through damaged skin. Entering the lungs or digestive tract, radioactive substances are distributed throughout the body with the bloodstream. At the same time, some substances are distributed evenly in the body, while others accumulate only in certain (critical) organs and tissues: radioactive iodine - in the thyroid gland, radioactive radium and strontium - in the bones, etc. Internal exposure can occur when eating food crop and livestock production obtained from contaminated agricultural land.
The duration of the presence of radioactive substances in the body depends on the rate of release and the half-life - the time during which the radioactivity is halved. The removal of such substances from the body occurs mainly through the gastrointestinal tract, kidneys and lungs, partly through the skin, oral mucosa, with sweat and milk.
Ionizing radiation can cause local and general damage. Local skin lesions are in the form of burns, dermatitis and other forms. Sometimes there are benign neoplasms, it is also possible the development of skin cancer. Prolonged exposure to radiation on the lens causes cataracts.
General lesions occur in the form of acute and chronic radiation sickness. Acute forms are characterized by specific lesions of the hematopoietic organs, gastrointestinal tract and nervous system against the background of general toxic symptoms (weakness, nausea, memory loss, etc.). In the early stage of the chronic form, increasing physical and neuropsychic weakness, a reduced level of red blood cells in the blood, and increased bleeding are observed. Inhalation of radioactive dust causes pneumosclerosis, sometimes cancer of the bronchi and lungs. Ionizing radiation inhibits the reproductive function of the body, affecting the health of future generations.
Works with sealed sources of radiation and open radioactive substances can be performed at the production site.
Sealed sources are sealed; most often these are steel ampoules containing a radioactive substance. As a rule, they use γ- and less often β-emitters. Sealed sources also include X-ray machines and accelerators. Installations with such sources are used to control the quality of welds, determine the wear of parts, disinfect skin and wool, treat seeds to kill insect pests, and in medicine and veterinary medicine. Working at these installations is fraught with danger only from external radiation.
Works with radioactive substances in the open form are encountered in the diagnosis and treatment in medicine and veterinary medicine, when radioactive substances are applied as part of luminous paints on dials, in factory laboratories, etc. For work in this category, both external and internal exposure are dangerous, since radioactive substances can enter the air of the working area in the form of vapors, gases and aerosols.
To take into account the unequal danger of different types of ionizing radiation, the concept of equivalent dose has been introduced. It is measured in sieverts and is determined by the formula
where k is a quality factor that takes into account biological effectiveness various kinds radiation compared to X-ray: k = 20 for α-radiation, k- 10 for proton and neutron fluxes; k- 1 for photon and β-radiation; D is the absorbed dose characterizing the absorption of the energy of any ionizing radiation by a unit mass of a substance, Sv.
The effective dose makes it possible to assess the consequences of irradiation of individual organs and tissues of a person, taking into account their radiosensitivity.
The radiation safety standards NRB-96, approved by Decree No. 7 of the State Committee for Sanitary and Epidemiological Surveillance of the Russian Federation on April 19, 1996, established the following categories of exposed persons:
personnel - people working with man-made radiation sources (group A) or who, due to working conditions, are in the area of their influence (group B);
the entire population, including personnel, outside the scope and conditions of their production activities (Table 21.2).
21.2. Basic exposure dose limits, mSv
|
Normalized value |
Service staff |
Population |
|
Effective dose |
20 per year on average for any 5 years, but not more than 50 per 1 year |
1 per year on average for any 5 years, but not more than 5 per 1 year |
|
Equivalent dose per year: |
||
|
in the lens |
||
|
on the skin |
||
|
on hands and feet |
The annual dose of exposure of the population from natural background radiation averages (0.1 ... 0.12) 10-2 Sv, with fluorography 0.37 * 10-2 Sv, with radiography of teeth 3 o 10-2 Sv.
The main dose limits for exposed people do not include doses from natural and medical sources of ionizing radiation and the dose received as a result of radiation accidents. There are special restrictions on these types of exposure.
Protection from external radiation is carried out in three directions: 1) by shielding the source; 2) increasing the distance from him to the workers; 3) reduction of the time spent by people in the irradiation zone. As screens, materials that absorb ionizing radiation well, such as lead, concrete, are used. The thickness of the protective layer is calculated depending on the type and power of radiation. It should be taken into account that the radiation power decreases in proportion to the square of the distance from the source. This dependency is used when implementing remote control processes. The time spent by workers in the zone of exposure to radiation is limited from the condition of compliance with the maximum radiation doses indicated in Table 21.2.
When working with open sources of radiation, the room where radioactive substances are located is isolated as much as possible. The walls must be of sufficient thickness. The surfaces of enclosing structures and equipment are covered with materials that are easy to clean (plastic, oil paint etc.). Work with radioactive substances polluting the air of the working area is carried out only in closed fume hoods (boxes) with filtration of the exhaust air. At the same time, sufficient attention should be paid to the efficiency of general and local ventilation, as well as the use of personal protective equipment (respirators, insulating pneumosuits with clean air supply, goggles, overalls, aprons, rubber gloves and shoes), which are selected depending on the properties of the used radioactive substances, their activity and type of work. Important preventive measures include dosimetric control and medical examination of workers. For individual dosimetric control devices IFKU-1, TLD, KID-6 and others are used; - and neutron radiation is measured with RUP-1, UIM2-1eM devices, and the volumetric activity of radioactive gases and aerosols in the air - with RV-4, RGB-3-01 devices.
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Sources of electromagnetic radiation
It is known that near the conductor through which the current flows, both electric and magnetic fields arise simultaneously. If the current does not change with time, these fields are independent of each other. At alternating current magnetic and electric fields are interconnected, representing a single electromagnetic field.
The electromagnetic field has a certain energy and is characterized by electrical and magnetic intensity, which must be taken into account when assessing working conditions.
Sources of electromagnetic radiation are radio and electronic devices, inductors, capacitors of thermal installations, transformers, antennas, flange connections of waveguide paths, microwave generators, etc.
Modern geodetic, astronomical, gravimetric, aerial photography, marine geodetic, engineering geodetic, geophysical works are carried out using devices operating in the range of electromagnetic waves, ultrahigh and ultrahigh frequencies, exposing workers to danger with an irradiation intensity of up to 10 μW/cm2.
Biological effect of electromagnetic radiation
A person does not see and does not feel electromagnetic fields, and that is why he is not always warned against the dangerous effects of these fields. Electromagnetic radiation has a harmful effect on the human body. In the blood, which is an electrolyte, under the influence of electromagnetic radiation, ion currents arise, causing tissue heating. At a certain intensity of radiation, called the thermal threshold, the body may not be able to cope with the heat generated.
Heating is especially dangerous for organs with an underdeveloped vascular system with low blood circulation (eyes, brain, stomach, etc.). If the eyes are exposed to radiation for several days, the lens may become cloudy, which can cause cataracts.
In addition to thermal effects, electromagnetic radiation has an adverse effect on the nervous system, causing dysfunction of the cardiovascular system, metabolism.
Prolonged exposure to an electromagnetic field on a person causes increased fatigue, leads to a decrease in the quality of work operations, severe pain in the heart, changes in blood pressure and pulse.
The assessment of the danger of exposure to an electromagnetic field on a person is made by the magnitude of the electromagnetic energy absorbed by the human body.
3.2.1.2 Electric fields of power frequency currents
It has been established that electromagnetic fields of currents of industrial frequency (characterized by an oscillation frequency from 3 to 300 Hz) also have a negative impact on the body of workers. The adverse effects of industrial frequency currents appear only at a magnetic field strength of the order of 160-200 A / m. Often, the magnetic field strength does not exceed 20-25 A / m, so it is sufficient to assess the risk of exposure to an electromagnetic field by the magnitude of the electric field strength.
To measure the strength of the electric and magnetic fields, devices of the "IEMP-2" type are used. The radiation flux density is measured by various kinds of radar testers and low power thermistor meters, for example, "45-M", "VIM", etc.
Electric field protection
In accordance with the standard "GOST 12.1.002-84 SSBT. Electric fields of industrial frequency. Permissible levels of tension and requirements for monitoring at workplaces." the norms of permissible levels of electric field strength depend on the time a person stays in the danger zone. The presence of personnel at the workplace for 8 hours is allowed at an electric field strength (E) not exceeding 5 kV / m. With electric field strength values of 5-20 kV/m, the time of allowable stay in the working area in hours is:
T=50/E-2. (3.1)
Work under conditions of exposure to an electric field with a strength of 20-25 kV / m should last no more than 10 minutes.
In a work area characterized by different meanings electric field strength, personnel stay is limited by time (in hours):
where and TE are, respectively, the actual and permissible time spent by personnel (h), in controlled areas with tensions E1, E2, ..., En.
The main types of means of collective protection against the impact of the electric field of industrial frequency currents are shielding devices. Screening can be general and separate. With general shielding, the high-frequency installation is closed with a metal casing - a cap. The unit is controlled through windows in the casing walls. For safety reasons, the casing is in contact with the earth of the installation. The second type of general shielding is the isolation of the high-frequency installation in a separate room with remote control.
Structurally, shielding devices can be made in the form of visors, canopies or partitions made of metal ropes, rods, nets. Portable screens can be designed in the form of removable peaks, tents, shields, etc. The screens are made of sheet metal with a thickness of at least 0.5 mm.
Along with stationary and portable shielding devices, individual shielding kits are used. They are designed to protect against the effects of an electric field, the intensity of which does not exceed 60 kV / m. The composition of individual shielding kits includes: overalls, safety shoes, head protection, as well as hand and face protection. The components of the kits are equipped with contact leads, the connection of which allows for a single electrical network and high-quality grounding (often through shoes).
Checked periodically technical condition shielding kits. The test results are recorded in a special log.
Field topographic and geodetic work can be carried out near power lines. electromagnetic fields overhead lines high and extra high voltage power transmissions are characterized by magnetic and electrical strengths, respectively, up to 25 A / m and 15 kV / m (sometimes at a height of 1.5-2.0 m from the ground). Therefore, in order to reduce the negative impact on health, the production of field work near power lines with a voltage of 400 kV and above, it is necessary either to limit the time spent in the danger zone, or to use personal protective equipment.
3.2.1.3 RF electromagnetic fields
Sources of electromagnetic fields of radio frequencies
The sources of the occurrence of electromagnetic fields of radio frequencies are: broadcasting, television, radar, radio control, hardening and melting of metals, welding of non-metals, electrical exploration in geology (radio wave transmission, induction methods, etc.), radio communication, etc.
Electromagnetic energy of low frequency 1-12 kHz is widely used in industry for induction heating for the purpose of hardening, melting, heating metal.
The energy of the low-frequency impulsive electromagnetic field is used for stamping, pressing, for connecting various materials, casting, etc.
For dielectric heating (drying wet materials, gluing wood, heating, heat setting, melting plastics), installations are used in the frequency range from 3 to 150 MHz.
Ultrahigh frequencies are used in radio communications, medicine, radio broadcasting, television, etc. Work with ultrahigh frequency sources is carried out in radar, radio navigation, radio astronomy, etc.
Biological effect of electromagnetic fields of radio frequencies
According to the subjective sensations and objective reactions of the human body, there are no particular differences when exposed to the entire range of HF, UHF and SHF radio waves, but the manifestations and adverse effects of exposure to SHF electromagnetic waves are more characteristic.
The most characteristic when exposed to radio waves of all ranges are deviations from the normal state of the central nervous system and the human cardiovascular system. Common in the nature of the biological action of high-intensity electromagnetic fields of radio frequencies is the thermal effect, which is expressed in the heating of individual tissues or organs. The lens of the eye, gallbladder, bladder and some other organs are especially sensitive to the thermal effect.
The subjective sensations of the irradiated personnel are complaints of frequent headache, drowsiness or insomnia, fatigue, lethargy, weakness, increased sweating, darkening of the eyes, absent-mindedness, dizziness, memory loss, unreasonable feeling of anxiety, fear, etc.
Among the listed adverse effects on humans, one should add a mutagenic effect, as well as temporary sterilization during irradiation with intensities above the thermal threshold.
To assess the potential adverse effects of electromagnetic waves of radio frequencies, the permissible energy characteristics of the electromagnetic field for a different frequency range are taken - electrical and magnetic strength, energy flux density.
Protection against electromagnetic fields of radio frequencies
To ensure the safety of work with sources of electromagnetic waves, a systematic monitoring of the actual values of the normalized parameters is carried out at workplaces and in places where personnel can be located. If the working conditions do not meet the requirements of the standards, then apply the following ways protection:
1. Screening of the workplace or radiation source.
2. Increasing the distance from the workplace to the radiation source.
3. Rational placement of equipment in the working room.
4. Use of precautionary measures.
5. The use of special energy absorbers to reduce radiation in the source.
6. Using the possibilities of remote control and automatic control, etc.
Workplaces are usually located in the zone of minimum intensity of the electromagnetic field. The final link in the chain of engineering protective equipment is personal protective equipment. As personal protective equipment for the eyes from the action of microwave radiation, special goggles are recommended, the glasses of which are coated with a thin layer of metal (gold, tin dioxide).
Protective clothing is made of metallized fabric and is used in the form of overalls, overalls, jackets with hoods, with goggles built into them. The use of special fabrics in protective clothing can reduce exposure by 100-1000 times, that is, by 20-30 decibels (dB). Goggles reduce the radiation intensity by 20-25 dB.
In order to prevent occupational diseases, it is necessary to conduct preliminary and periodic medical examinations. Women during pregnancy and lactation should be transferred to other jobs. Persons under the age of 18 are not allowed to work with radio frequency generators. Persons who have contact with sources of microwave and UHF radiation are provided with benefits (shortened working hours, additional leave).
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