Effects of Radiation

Radiation is energy that moves as waves and makes up the electromagnetic spectrum. The electromagnetic radiation spectrum is classified into two major types: non-ionizing radiation and ionising radiation. Radiation is used as a therapy for treating cancers and tumours. But these treatments have long term side effects. The department of oncology and radiotherapy uses radiation. Not just human beings, the environment also faces the harmful effects of radiation.

Effects of Radiation

Table of Contents

What Is Radiation?

Radiation is defined as the emission of energy in the form of electromagnetic waves. These can be in the form of gamma radiation, radio waves, heat waves or particle radiation which includes alpha and beta radiation. The other form of radiation is gravitational radiation. There side effects of radiation on human begins.

Radiation may affect living things by damaging the cells that make up the living organism. The effects of radiation on a cell are random. That is, the same type and amount of radiation could strike the same cell many times and have a different effect, including no effect, each time.

Learn more about the types of radiation here.

Classification of Radiation Effects

The effects faced by the human body due to radiation is classified into two categories:

  • Threshold effects
  • Non-threshold effects

Threshold Effects:

It occurs when levels of radiation exposure are tens, hundreds, or thousands of times higher than the background, and usually when the exposure is over a very short time, such as a few minutes. They do not occur when doses of radiation are smaller than the threshold value.

Non-threshold Effects:

It can occur at any level of radiation exposure. However, the risk of harmful health effects of radiation generally increases the amount of radiation absorbed. The most studied non-threshold effect is cancer. Studies are somewhat complicated by the fact that most cancers are not caused by radiation, exposure to a particular dose may cause cancer in one person but not in another, and cancer often doesn’t appear until many years after the exposure.

Radiation Exposure Pathways

We are frequently exposed to two types of radiation:

  • Natural radiation includes naturally existing non-ionising and ionising radiation sources from the ground, the sun, outer space, and even from within our own bodies.
  • Man-made ionising and non-ionising sources such as microwaves, smoke detectors, electrical power lines and cell phones. 

The three fundamental radiation exposure pathways are given below:

  • Direct or external exposure: Radioactive matter coming into direct contact with the skin.
  • Inhalation: Breathing radioactive smoke, gases, dust or particles into the lungs. 
  • Ingestion: Drinking or eating materials that possess radioactive elements.

Contamination happens when a person makes physical contact with, inhales or ingests radioactive substances. Contamination may happen when radioactive substances are released into nature as a result of an accident or an event in nature. After physical contact, people and connected property should be decontaminated.

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Effects of Radiation on Human Body

The side effects of radiation cause ionization of atoms which affects the molecules of the human body which further affects the cells, tissues, organs, and the whole body. Following are the body parts that are most commonly affected by the radiation:

  • Hair

When the radiation exposure is more than 200 rems, the hair loss becomes quick and it occurs in clumps.

  • Brain

When the radiation exposure is more than 5000 rems, the nerve cells and small blood vessels get affected resulting in complete damage to the brain.

  • Thyroid

The thyroid gland is likely to get damaged due to the presence of a sufficient amount of radioactive iodine. But the intake of potassium iodide can reduce the effects of radiation.

  • Blood System

When the radiation exposure is around 100rems, the first symptom is a fall in lymphocyte count. The other symptoms are mild radiation sickness and flu.

  • Heart

When the radiation exposure is between 1000 and 5000 rems, the small blood vessels in the heart start to rupture resulting in heart failure.

  • Reproductive Tract

The reproductive tract can be easily damaged as the cells get divided rapidly and the exposure required for the side effects is less than 200 rems. Prolonged exposure can result in radiation sickness making the victim sterile.

Frequently Asked Questions – FAQs


What is radiation?

Radiation is defined as the emission of energy in the form of electromagnetic waves.

How are radiation effects classified?

Radiation effects are classified as:
  • Threshold effects
  • Non-threshold effects
  • Q3

    State true or false: Non-threshold effect can occur at any level of radiation exposure.


    On which body parts radiation affects the most?

    Radiation affects on:
  • Hair
  • Brain
  • Heart
  • Reproductive Tract
  • Q5

    Does the radiation affect the thyroid gland?

    Yes, radiation affects the thyroid gland.
    Stay tuned with BYJU’S to learn more about other Physics related concepts.

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