1. Natural and man-made radiation exposure
1.1 Introduction
What are rays?
Radiation is always and everywhere! (RNU)
Even we humans radiate and have an internal radioactivity of around 9,000 Becquerels (Bq). 9,000 nuclear decays per second, that's almost 800 million per day.
Streams of energy or particles emitted by a source produce rays. The biggest is the sun. Their radiation makes life on earth possible in the first place; but it can also endanger human health.
Radiation can bring life or death. Only a few rays can be seen, heard, smelled, tasted (ozone formation when electromagnetic waves flash over in waveguides) or directly felt. (RNU)
The claim that radiation is dangerous is right and wrong. Just as the finding table salt is deadly. It depends on how much is consumed and when. For radiation and table salt, the levels that are lethal are known, but also levels that appear to cause no long-term harm. Radiation destroys cancer cells . Laser beams eliminate cataracts .
Ionizing rays
Rays emanating from radioactive substances arise spontaneously or artificially through the induced decay of atomic nuclei . In the process, matter is placed in an electrically charged state. They ionize . This radiation is part of nature and a product of human creativity.
1.2 Types of Ionizing Radiation
Four types of radiation are produced when radioactive materials decay :
1.2a Alphastrahlung
Partial ash flow from nuclei of the element helium (2 protons and 2 neutrons) hardly penetrates the skin and cannot penetrate paper
1.2.b Beta Radiation
Particle flow of negatively or positively charged electrons ( beta particles ) is absorbed by tissue and materials.
1.2.c Gamma Radiation
Electromagnetic radiation penetrating tissue is partially absorbed and is attenuated by material.
1.2.d Neutron radiation
Neutrons are electrically neutral elementary particles. The fission of heavy atomic nuclei ( uranium ) generates energy and radiation. (nuclear reactors, atomic bomb)
1.3 Natural exposure to radiation
a cosmic radiation ( primary and secondary radiation)
b terrestrial radiation ( natural radioactive substances in the ground)
c internal radiation (incorporated natural radioactive substances , radon, potassium-40 )
1.3.a Cosmic radiation exposure
Solar flares and stellar outbursts ( super nova ) produce primary cosmic proton radiation ( primary radiation ). After contact with the earth's atmosphere, they are converted into secondary cosmic rays . The secondary radiation consists of protons , electrons , mesons , neutrinos and electromagnetic waves. The atmosphere consists of radiation belts and electron belts that serve as a protective cover for the earth . Due to this shielding effect of the atmosphere , the intensity of cosmic radiation decreases with increasing altitude.
1.3.b terrestrial radiation exposure
Radionuclides , which were created during the creation of the universe, are far from decaying due to their long half-lives .
Radionuclides are unstable atomic nuclei or nuclides that can spontaneously convert to become radioactive, emitting gamma rays in the process. They convert into stable nuclides directly or via radioactive intermediates. Each radionuclide has a characteristic physical half-life. (More on that shortly)
Terrestrial radiation consists of:
- Thorium-232 (half-life 14 billion years)
- Uranium-238 (half-life 4.4 billion years)
- Uranium-235 (half-life 700 million years)
- Potassium-40 (half-life 1.3 billion years)
The terrestrial radiation is triggered by the natural radionuclides in the soil and in the rocks of the earth. It reaches humans via the ground, spring and river water, plants and animals via the food chain. They are present in all building materials.
Terrestrial radiation can also have damaging reactions on cells and change or destroy the genetic material .
The intensity of the radiation depends on the local conditions on our globe. In Germany, the radiation exposure is about 0.4 mSv/year on average. The highest value is in the Bavarian Forest and low mountain ranges (up to 1.3 mSv/year), the lowest in Northern Germany (about 0.25 mSv/year). In Iran 6 mSv/year.
1.3.ci internal radiation exposure
Building materials used in house construction decompose over time and are inhaled by people. Radon 222 is the main part of the radiation . Potassium , rasium and thorium are stored when we eat .
1.4 civilization radiation exposure
a medical ( X-ray and gamma radiation in medicine )
b flying and space travel
c nuclear weapons ( fallout from nuclear weapon tests )
d nuclear power plants ( accidents, radiation exposure )
e small sources (brake radiation from screens , mobile phones, other emitters)
1.4.a medical radiation exposure
used by medical X-ray diagnostics , nuclear medicine and radiotherapy . X-ray diagnostics accounts for the largest share at 90%. In dentistry, 23.5 million recordings are made every year.
X-rays damage the genetic material . A small dose of radiation takes a long time to repair the damaged cell. In the case of weakly irradiated cells, the repair program comes much later or not at all. Lower doses of radiation have a greater risk of cancer than previously thought.
1.4.b Radiation exposure during flights and space flights
Supersonic flights at altitudes of up to 16 km cause high radiation exposure.
The measurements of the dose rate on Concorde flights show dose rates of flight altitude and geographical latitude.
1.4.c Radiation Exposure from Nuclear Weapons
On August 6, 1945, Hiroshima was destroyed. Here it was revealed how dramatically the atomic bombs , a weapon of mass destruction, bring death and mutation damage worldwide. Numerous test explosions above and below ground using hydrogen and neutron bombs are increasingly polluting our environment with higher levels of radiation.
In an atomic bomb, fissile material uranium-235 or plutonium-239 is fissioned with a nuclear reaction . In hydrogen bombs, hydrogen molecules (deuterium = H2 or tritium = H3) are combined to form helium. This is where the fusion process takes placeimitated the sun. Modern bombs are a hybrid of atomic and hydrogen bombs.
1.4.d Radiation exposure from nuclear power plants
Accidents in nuclear power plants cause global radiation exposure. The Chernobyl reactor accident shows the terrible mutational damage that occurs. Here are pictures that speak for themselves .
1.4.e Small sources ( electrosmog )
Cell phones, cordless phones, and computer monitors generate radiation. Transmission masts for mobile communications and radar systems pollute our environment with electromagnetic fields .
The blood-brain barrier becomes permeable under the influence of electromagnetic fields (EMF) . The formation of the hormone melatonin in the pineal gland is reduced. If melatonin is missing , the free radicals in the cells increase. The risk of cancer increases. Leukemia, brain tumors and cancer are the result. Cell phones can change brain waves . cause damage to the genetic material and affect cellular processes .
1.4.f Rohphosphate
Cadmium contained in phosphate fertilizers .
Cadmium is a heavy metal found in almost all soils, which accumulates in the adrenal cortex of humans and animals and thus leads to damage to health. Cadmium is toxic in the smallest amounts! Methane enters the atmosphere
through livestock farming (in addition to defecation and pooping) . The amount of phosphates that may be used is stipulated by EU law .
2. Energy and equivalent dose
2.1 Radiation Dose
Is the effect of a quantity of radiation . It is physical, chemical or physiological - biological in nature.
2.2 Dose Rate
= dose rate is the change in dose over time = dose rate (DL) = dose (D) time (t)
2.3 Ionendosis
the formation of ions in the irradiated amount of air or gas is called ionization. The size of the energy dose can only be calculated and not measured directly.
The dose of ions formed by the irradiation in the volume element = ion dose (ID) = generated charge quantity (Q) mass of the volume element (m)
2.4 absorbed dose
Energy that hits a material during irradiation and is absorbed.
2.4.a Absorption
Absorption is the absorption of a substance and its even distribution!
- absorption of gases in other substances (carbon dioxide in mineral water)
- absorption of X-rays or radioactive radiation)
- Absorption of liquids or gases through the skin (e.g. skin creams)
Absorption of ionizing radiation, the shielding is made of lead for protection.
2.4.b Activity
Radioactive nuclides decay in their nuclei. This creates rays. The number of nuclear decays determines the unit of activity.
Activity (A) = decay rate = number of nuclear decays time unit (t) / time unit (t) absorbed dose
The absorbed dose = the ratio of the absorbed energy of the irradiated substance and its mass. The unit of absorbed dose is Joule related to the mass of the irradiated body in kg (= J/kg).
Units: Absorbed dose rate: 1 Gray/s Ion dose rate: 1 Ampere/kg Equivalent dose rate: 1 Watt/kg
2.5 Dose Equivalent
The biological effect of a quantity of radiation e = dose equivalent = absorbed dose x Q (quality factor)
2.5.a Quality Score
is the biological effectiveness of X-ray radiation on organs with 250 keV energy, Q = 250 keV = 1.
With the same energy dose (Q = 250 keV = 1), the extent of the biological reaction of the type of radiation and the energy is examined. The quality factor indicates how much a type of radiation affects the organism with the same absorbed dose.
Unit of measurement = absorbed dose 1 joule/kg corresponds to 1 sievert (Sv)
The equivalent dose is the effect of ionizing radiation on humans. The dose of the type of radiation on organs is given in mSv. They are used to assess hazards.
The quality factor of types of radioactive radiation depends on the type of radiation and the charge origin and loads of equivalent doses
2.6 Effective Dose
The radiation sensitivity of the organs and is the product of the equivalent dose and the tissue weighting factor .
The effective dose is the sum of equivalent doses of the individual organs and tissues irradiated. The weighting factors represent the different radiation sensitivity of the organs and tissues.
The unit of effective dose is the sievert (mSv).
2.7 What is Becquerel? (abbreviation Bq)
is the activity of a substance. It indicates the number of nuclear decays that take place in a given radioactive substance per second. Becquerel = 1 nuclear decay/second
2.8 Half-life (HWZ
Every radioactive substance has a decay rate. This activity is unstoppable (ageing sprout). The radioactive radiation becomes weaker and weaker and only stops when all unstable nuclei have decayed into stable nuclei.
2.8a Physical half-life
half of the original amount of radioactive material has decayed. Depending on the radionuclide, the physical half-life varies between fractions of a second and billions of years.
2.8.b Biological half-life
if half of the original amount of a radioactive substance taken up by the body is excreted or broken down by the organism.
2.8.c Effective half-life
is the time resulting from the physical and biological half-life. This time is important for the actual risk to humans when radioactive substances are absorbed into the body.
2.9 Artificial Radiation Sources
2.9a X-ray radiation
During an X-ray examination, the radiation is partially absorbed by the human body. This can lead to biological changes in the cells .
With most types of X-ray examination , doses occur that are significantly lower than natural radiation exposure. For examinations of the stomach and intestines, blood vessels and CT examinations, the dose is significantly higher.
2.9b nuclear power plants
Nuclear power plants belong to the artificial radiation sources. During normal operation and in the event of an accident, they release radioactive substances into the environment via the exhaust air and waste water.
2.9.c The static electric field
Electric charges exert forces on each other.
The unit of measure = volts per meter (V/m)
If field forces act on conductive materials, electrical charges are created on the surface of his body ( influence) . The surface is charged while the inside of the body becomes practically field-free. In practice, this effect is used to shield external fields ( Faraday cage principle ).
When a person is exposed to strong electric fields from the outside, his body surface becomes electric due to the influence . In the process, small equalizing currents flow inside the body (body currents).
A shock can occur when you touch a doorknob or when you walk across certain carpeted floors. The carpet and the doorknob were charged differently than the surface of the skin. Voltage equalization occurs, and a small leakage current flows.
Leakage currents of this kind can range from crackling to a powerful thump. Leakage currents can occur on large metal surfaces under high-voltage lines , some of which flow through the inside of the body and are quite painful. The electric field can be illustrated by lines of force between the poles .
2.9.d The magnetic field
Magnetic fields are moving electrical charges. Alternating electric and magnetic fields always form an inseparable unit. Wherever there is a changing electric field, a magnetic field forms perpendicular to it.
Every changing magnetic field creates a changing electric field around it . Whenever electrical charges are moved through the conductors, i.e. when current flows, a magnetic field is created around the conductor. If the current continuously changes its direction, as with 50 Hz alternating current , the polarity of the magnetic field is reversed in the same rhythm – we are dealing with an alternating magnetic field of the same frequency.
The higher the current, the higher the magnetic field strength.
This is measured in amperes per meter (A/m). Or with the magnetic flux density with the unit Tesla (T)
80 A/m corresponds to around 100 micro tesla, that is 0.0001 T.
Magnitude of the magnetic fields in the energy supply.
2.9.e Radio and microwaves
High-frequency radiation is radiated from antennas. It propagates at the speed of light, transferring energy as it does so.
In the electromagnetic spectrum, the radio frequency radiation range is between about 100 kilohertz and 300 gigahertz. The electric and magnetic fields change direction several thousand, even millions or billions of times per second. Since the electrical and magnetic components are very closely coupled to each other, the effect of this radiation can hardly be traced back to the individual effects of the two components.
2.9.f Effects of high-frequency fields
The effect of high-frequency radiation on biological systems and on the human body depends on the depth of penetration of the radiation into human tissue and is highly frequency-dependent. Medium wave radio
electromagnetic fields are in the megahertz range and have penetration depths of 10 to 30 cm. Mobile communications with frequencies around 1 gigahertz (GHz) that are a thousand times higher , the radiation only penetrates a few centimeters deep into the tissue.
2.9.g Ultraviolet Radiation
the sunlight promotes blood flow and circulation and stimulates vitamin D formation and increases well-being. Unfortunately, sunbathing also has its downsides.
In addition to light and heat, the sun emits high-energy ultraviolet (UV) radiation .
The dramatic increase in skin cancer cases is partly due to increased UV exposure .
Ultraviolet radiation is the most energetic. in the electromagnetic spectrum, after visible light, it is the transition to ionizing radiation. The short-wave UV-C radiation and large areas of UV-B radiation are held back by the ozone layer and hardly reach the earth's surface.
If the ozone content in the atmosphere falls, the proportion of short-wave UV ranges that can penetrate to the earth's surface and whose biological effectiveness is particularly high increases.
3. Genetic and somatic radiation damage
3.1. effects of radiation on humans
The effects of external radiation can be avoided by staying close to the source of radiation for only a short time (brief sunbathing), by shielding yourself (sunscreen) or by keeping a safe distance (hiding in the shade).
If the radiation source is in the human body, one must wait until the radionuclide has decayed or been excreted from the body. Elimination can be achieved with medication.
Radioactive substances in human organs themselves emit alpha and beta particles and generate large numbers of ions.
Gamma rays of sufficient energy can reach all parts of the body when exposed to external or internal radiation. Radioactive substances that have been absorbed by the human body are stored in the organs.
3.2 The effects of radioactive substances on the body
Nuclides damage the body in different ways. Strontium-90 is mistaken for calcium by the body and is deposited in the bones . This causes leukemia and bone cancer.
Cesium-137 is mistaken for potassium by the body and is deposited in the muscles. Radioactive substances can cause genetic radiation diseases in many parts of the body. Therefore the smallest dose of radioactivity is dangerous!
3.3 The radiobiological reaction chain (slide 2)
If ionizing radiation hits an organism, physical, chemical and biological effects occur in the individual cells .
The ionization and the excitation lead to changes in the atomic shells. (During ionization, an electron is separated from the atomic shell, shifted within the shell during excitation and raised to a higher energy level).
The ionization can be reversed by accepting a free electron (recombination). When the displaced electron has returned to its original place.
A cell consists of about 80% water and is converted into hydrogen peroxide (H2O2) by ionizing radiation . Hydrogen peroxide (high in oxygen) is a cytotoxin. The cell shows altered biological behavior or is no longer functional.
However, this does not always lead to the damage being recognized from the outside. The human body has the ability to recognize damaged and non-functional cells and to break them down with the help of the immune system . The biological radiation effect then has no health consequences for the person concerned. If the defense system fails, radiation damage occurs. It can be recognized immediately or after a long time.
The cell nucleus contains the ( DNA ). It controls and regulates cell functions and is more sensitive to radiation than cell plasma .
A biological effect of irradiation can be observed in cells that are beginning to divide or are in the process of dividing at the time of irradiation. The repair mechanisms are then only insufficiently effective.
A distinction is made between somatic and genetic damage. Somatic damage (damage to the body) only occurs in the irradiated person, genetic damage (hereditary damage) in the offspring. Not only direct descendants are affected, but also later generations.
3.4 Somatic radiation damage
are not inheritable. Even the smallest radiation leads to damage to the bone marrow (part of the blood-forming system).
cause somatic damage
- blood (leukemia)
- lung
- breast and thyroid cancer
- cancer of all types
- reduced fertility
- changes in the blood
- mental and physical damage to the unborn child
Somatic damage has been observed in workers in the fluorescent paint industry (clock faces contain tritium ) and in the medical field (radiation therapy, X-ray diagnostics). ( Hence the lead coat to protect against X-rays)
Recent investigations in Trier showed that electromagnetic fields from radar systems of the former NVA ( National People's Army ) caused somatic damage . Flight personnel have been diagnosed with somatic illnesses
as a result of constant exposure to high levels of cosmic radiation (from solar flares or super nova star outbursts).
Acute radiation death is
caused by catastrophes at nuclear facilities ( Chernobyl 1986 ) or by an atomic bomb explosion ( Nagasaki 1945) .
Depending on the location and sensitivity to radiation, the following symptoms of acute radiation syndrome occur in addition to burns and injuries
- Dizziness
- Vomiting
- Fever
- Diarrhea
- Apathetic
- Death after a few days.
But even seemingly uninjured people suddenly fall ill after one to two weeks:
- vomiting blood,
- spots all over the body,
- later hair loss and bloody stools;
- febrile infections occur due to a lack of white blood cells.
- Survivors usually face a lifelong ordeal.
3.5 Genetic damage,
are caused by changes in the chromosomes contained in the cell nucleus if they are part of a germ cell . Structural changes in germ cells lead to altered genetic information in the offspring. A genetic mutation occurs . If, on the other hand, a normal body cell is changed, the descendants are not damaged, only the person affected. Radiation damage can also be repaired in a germ cell. This protects the genetic information of living beings from natural radiation.
There are now two fundamentally different modes of inheritance: ( Mendel, 1865) In the case of a dominant mutation , the offspring of the irradiated person are directly affected. A recessive mutation is more insidious. It can be passed on unnoticed, which can take many generations.
The prerequisite is that an egg cell and a sperm with the same recessive mutation meet. A population can be heavily riddled with hereditary defects without this being detected. When a critical spread is reached, the damage can then become visible (so-called hereditary catastrophe)
Here is a selection of diseases that can arise from genetic mutations :
Allergies,
epilepsy,
arthritis, (inflammation of the arteries)
kidney stones,
liver damage , dementia,
eye diseases,
muscle weakness,
brain degeneration, (regression)
arteriosclerosis, (hardening of the arteries)
heart diseases, etc.