What is Radiation ?
The process of emission and propagation or transmission of energy in the form of waves, particles or rays through a material medium or any space is called Radiation . Radiation can
be of number of types such as heat waves or particle radiation , radio waves , gamma radiation,
microwaves, infrared, visible light, ultraviolet, x-rays ,etc depending upon their nature and characteristics .
Types of Radiation
Types Of Radiation: Radiation is energy that is emitted by a source, then travels through a medium, such as air, until it is absorbed by matter. Based on the energy of the radiated particles, they are classified as follows:
1 Ionizing radiation
2. Non-ionizing radiation
Ionizing Radiation : Radiation that produces ions with sufficient energy in the matter at the molecular level upon the interaction is called Ionizing Radiation. In other words, it can remove tightly bound electrons from its orbit, thus causing the atom to become further charged or ionized , thus when interacting matter is a human body, resulting in significant damage including damage to DNA and denaturation of proteins.
Since ionizing radiation is caused due to unstable atoms that either have excess energy or mass or both. Therefore to get back to a stable state, they have to release the extra mass or energy in the form of radiation to acquire their initial state .
The different types of Ionizing Radiations are:
Alpha particles
Beta particles
Gamma rays
X-rays
Effects of Radiation on Human Body
Exposure to very high levels of radiation may affect living things by damaging their cells that make up the living organism which can further cause acute health effects such as skin burns and acute radiation syndrome (“radiation sickness") .The effects of radiation on a cell are random i.e the same type and amount of radiation could strike the same cell many times and have different effect, including no effect. The most common early side effects such fatigue (feeling tired) and skin changes , hair loss, etc.It can also cause mouth problems when radiation treatment is given to this area .
Whether the source of radiation is natural or man-made, there will be some biological effects that overall may result into Symptoms of radiation sickness may include Weakness, fatigue, fainting, confusion , Bleeding from the nose, mouth, gums, and rectum, bruising, skin burns, open sores on the skin, sloughing of skin, etc whether it is a small dose of radiation or a large dose.
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Following are Biological Effects of Radiation
(1) Hair : Radiation causes quick losing of hair in clumps generally when 200 rems or higher exposure is there.
(2) Brain: Like the heart, radiation kills nerve cells and small blood vessels, and can cause seizures and immediate death and also Since brain cells do not reproduce and they won't be damaged directly until and unless the exposure is 5,000 rems or greater.
(3) Blood System: the blood's lymphocyte cell count will be reduced, when a person is exposed to around 100 rems leaving the victim more susceptible to infection and which is often referred to as mild radiation sickness. symptoms of radiation are sickness mimic and of flu and may go unnoticed unless a blood count is done . Data from Hiroshima and Nagaski, suggests that symptoms may persist for up to 10 years and may also have an increased long-term risk for leukemia and lymphoma.
(4) Genetic Effects due to Mutation of the reproductive cells passed onto the offspring of the exposed individual ,also many chemical agents as well as biological agents (such as viruses) that cause mutations.
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(5) Heart : Immediate damage to small blood vessels and probably cause heart failure and death directly when there is intense exposure to radioactive material at 1,000 to 5,000 rems
(6) Gastrointestinal Tract : When the victim's exposure is 200 rems or more,the Radiation damage to the intestinal tract lining will cause nausea, bloody vomiting and diarrhoea . Thus will begin to destroy the cells in the body that divide rapidly. These include blood, reproductive and hair cells, which harms their DNA and RNA of surviving cells.
(7) Reproductive Tract : Reproductive tract cells divide rapidly thus these areas of the body can be damaged at rem levels as low as 200. Long-term, some radiation sickness victims will become sterile.
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Classification of Radiation Effects
Biological effects of radiation are typically divided into two categories ,the first category includes exposure to high doses of radiation over short periods of time producing acute or short term effects while the second category represents exposure to low doses of radiation over an extended period of time producing chronic or long term effects. The high doses of radiation tend to kill cells , while low doses tend to change them or damage them . High doses can kill so many cells that tissues and organs are damaged in turn may cause a rapid whole body response often called the Acute Radiation Syndrome (ARS). The effects of low doses of radiation occur at the level of the cell, and the results may not be observed for many years as the low doses often spread out over long periods of time thus cannot cause an immediate problem to any body organ.
FAQs on Effects of Radiation
1. What is radiation and what are its primary sources?
Radiation is the process of emitting or transmitting energy in the form of waves or particles through space or a material medium. It originates from both natural and man-made sources. Natural sources include cosmic rays from space, radioactive elements in the Earth's crust like uranium, and radon gas. Man-made sources are created artificially for uses such as medical X-rays, nuclear power generation, and microwaves for cooking.
2. How is radiation classified based on its effect on atoms?
Based on the energy of the radiated particles and their ability to interact with matter, radiation is classified into two main types:
- Ionizing Radiation: This type carries enough energy to remove tightly bound electrons from atoms, creating ions. This process can damage biological tissues. Examples include alpha particles, beta particles, gamma rays, and X-rays.
- Non-ionizing Radiation: This type has less energy and cannot remove electrons from atoms, but it can excite them. Examples include visible light, microwaves, infrared, and radio waves.
3. What are the main biological effects of high-dose radiation on the human body?
Exposure to high levels of ionizing radiation can cause significant damage to the body by killing cells. Key effects include:
- Blood System: A dose of around 100 rems can reduce lymphocyte cell counts, making a person susceptible to infection.
- Gastrointestinal Tract: Doses of 200 rems or more damage the intestinal lining, leading to nausea, vomiting, and diarrhoea.
- Hair: Rapid hair loss can occur with exposures of 200 rems or higher.
- Reproductive Tract: Rapidly dividing cells in the reproductive system are sensitive and can be damaged by doses as low as 200 rems, potentially causing sterility.
- Brain: Extremely high doses (5,000 rems or more) can kill nerve cells and cause immediate death.
4. What are the initial symptoms of acute radiation sickness (ARS)?
The first signs of acute radiation sickness, which occurs after a large dose of radiation over a short period, often appear within hours. Common early symptoms include nausea, weakness, fatigue, and fainting. In many cases, these initial symptoms can be similar to those of a severe flu. Depending on the dose, other effects like skin burns, open sores, and bleeding from the nose or mouth may follow.
5. What is the difference between the acute and chronic effects of radiation?
The effects of radiation are distinguished based on the dose and duration of exposure:
- Acute effects result from exposure to a high dose of radiation over a short time. These effects, like radiation sickness or skin burns, appear quickly because the high dose kills a large number of cells, leading to tissue and organ damage.
- Chronic effects result from exposure to low doses of radiation over a long period. These effects, such as an increased risk of cancer or genetic mutations, may not be observable for many years as the low doses tend to damage or alter cells rather than kill them outright.
6. Why is ionizing radiation considered more dangerous to living organisms than non-ionizing radiation?
Ionizing radiation is more dangerous because it possesses enough energy to forcibly remove electrons from atoms and molecules within cells. This ionization creates highly reactive free radicals that can break chemical bonds and cause significant damage to critical biological structures, most importantly the DNA molecule. Damaged DNA can lead to cell death, mutations, and cancer. In contrast, non-ionizing radiation lacks the energy to do this and its primary effect on tissue is heating.
7. How does radiation exposure lead to genetic mutations?
Genetic mutations from radiation occur when ionizing radiation strikes the reproductive cells (sperm or egg cells) and alters their DNA. The energy from the radiation can cause direct breaks in the DNA strands. While cells have mechanisms to repair this damage, the repairs are not always perfect. An incorrect repair results in a permanent change in the DNA sequence, known as a mutation. If this mutated cell is involved in reproduction, the genetic change can be passed on to offspring.
8. Are there any beneficial applications of radiation?
Yes, despite its potential dangers, radiation has many critical and beneficial applications across various fields. In medicine, it is used in X-rays for diagnostics and in radiation therapy to target and destroy cancer cells. In industry, it is used for sterilizing medical equipment and food products (irradiation), and for inspecting welds and structures (industrial radiography). In science, radioactive isotopes are used for carbon dating to determine the age of ancient artefacts.
9. Can the human body recover from radiation damage?
The body's ability to recover from radiation damage depends almost entirely on the dose received and the duration of exposure. The body has natural mechanisms to repair or replace damaged cells. After a low dose, the body can often recover fully with few long-term effects. However, after a high dose, a massive number of cells may be killed too quickly for the body to repair or replace them, leading to severe organ failure, a condition known as Acute Radiation Syndrome (ARS), and potentially death.
