Radioactive Food Contamination

8/13/2019 Radioactive Food Contamination

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RadioactiveFoodContamination


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What is radiation?

Radiation is particle or wave or photon(energy) moving or travelling in space or

medium (object).

The particle is alpha, beta, protons andneutronswhile the wave (or photon) is x-

ray , gamma ray, radiowaves,microwaves, ultraviolet rays, infra red .


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Radiation can be divided into two categories:1. Ionizing radiations

2. Non-ionizing radiations

Ionizing radiations Ionizing radiations means radiations that can

ionize atoms (i.e. remove electrons from orbit ofatom).

These radiations are therefore high energyradiations because it requires energy to ionizeatoms.

Categories of Radiation


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Non-ionizing Radiations

Non-ionizing radiations are low energyradiations that cannot ionize atoms.

Examples of non-ionizing radiations are radiowaves, microwaves, infra-red, visible light and

ultraviolet rays.

Except for visible light, all radiations areinvisible.

This whole topics is only concerned withionizing radiations only, i.e. x-rays, gammarays, and particle radiations (alpha, electron,proton and neutron beam.


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The ElectromagneticSpectrum


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Sources of radiation

X-rays are produced whenever chargedparticle decelerate (slowing down,

change direction or stopped).

The charged particle can be eitherelectrons, protons or alpha particles.

The x-rays produced is calledbremsstrahlung x-rays.


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Bremsstrahlung x-rays is the type of x-raysthat is produced by x-ray machines.

Gamma rays

Gamma rays is physically similar to x-rays

in every aspects. The only differencebetween them is the method ofproduction.


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Gamma rays are produced byradioactive materials.

Radioactive materials are substances thatare undergoing radioactive decay.


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Particle radiations

Particle radiations such as electron,proton, neutron and alpha radiations are

produced whenever any of theseparticles are accelerated to a very highspeed.

These particles are accelerated to a veryhigh speed in a machine called anaccelerator.


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What is radioactivity? Radioactivity (or radioactive decay) is the

spontaneous disintegration of atomic nuclei.

The nucleus emits particles, particles, and

gamma rays during this process.


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Atoms are radioactive because the nucleus is

unstable. This is due to imbalances in the numberprotons and neutrons in the nucleus.

Through radioactive decay, the nucleus

approaches a more stable neutron to protonratio.

A radioactive atom is usually called aradionuclide or radioisotope.

Radioactive substances can be natural or man-made.


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Our world is radioactive and has been since itwas created.

Over 60 radionuclides (radioactive elements)can be found in nature, and they can beplaced in three general categories:

1. Primordial- from before the creation of the Earth

2. Cosmogenic - formed as a result of cosmic ray

interactions

3. Human produced- enhanced or formed due to

human actions (minor amounts compared to

natural)


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Biological effects of radiation Biological effects of radiation in living organisms

results from effects on cells.

biological effects of radiation on living cells may

result in three outcomes: (1) injured or damaged cells repair themselves, resulting

in no residual damage;

(2) cells die, much like millions of body cells do everyday, being replaced through normal biologicalprocesses; or

(3) cells incorrectly repair themselves resulting in abiophysical change.


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The amount of damage to the bodydepends on the following factors:

1. The dose of radiation

2. The size of area of the body exposed

3. The type of cells of the body exposed


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Radiation Dose

Radiation dose refers to the amount ofenergy absorbed by the tissue from the

radiation (remember that radiation isenergy that is travelling).

In simple form, the longer the body is

exposed to the radiation the more dose isreceived by the tissue.


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There is a threshold dose when exceededwill results in the effect can be seen.

For example, redness of the skin. After acertain amount of dose is reached, thenredness on the skin can be seen. Below

the threshold dose, no redness of skin canbe seen.


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This type of effects is called deterministiceffects. Other examples of deterministiceffects are vomiting, alopecia, diarrhea,

mucositis, malaise, leucopenia,thrombocytopenia, erythrocytopenia, anderythema.

There is however, effects in which there is no

threshold dose. This means there is nominimum dose for the effects to occur. Thiseffect is called stochastic effects.


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A stochastic effect is an effect which may or may

not occur after irradiation.

However, the probability of occurrence increaseswith increasing dose but the severity in affectedindividuals does not depend on the dose.

Therefore, there is no threshold dose for stochasticeffects which means there is no minimum dose forthe effect to occur.

Examples of stochastic effects are cancer andgenetic diseases (diseases affecting offspring of theexposed person).


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Radioactive food contamination

vs food irradiation Radioactive food contamination means food that

are contaminated by radioactive substances.

Foods can become contaminated withradioactive materials when they are released asthe result of a nuclear or radiological emergency.

In these circumstances, radioactive materialfalling from the air or carried in rain water or snow,can deposit on the surface of foods like fruits andvegetables or animal feed.


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Also, over time, radioactivity can build up withinfood, as radionuclides are transferred through soilinto crops or animals.

Radioactivity can also be washed into rivers, lakesand the sea where fish and seafood could takeup the radionuclides.

The severity of the risk depends on theradionuclide mix and the level of contaminantreleased.


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What are the potential health effects ofconsuming contaminated food?

Consuming food contaminated with radioactive

material will increase the amount of radioactivitya person is exposed to and could increase thehealth risks associated with exposure to radiation.

The exact effect will depend on whichradionuclides have been ingested and theamount.


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According to data reported so far, radioactiveiodineand caesiumare the main contaminants,and concentrations in some food samples have

been detected at levels above the regulatorylimits.

Radioactive iodine has a half-life of eight days

and decays naturally within weeks. If ingested, itcan accumulate in the body, particularly thethyroid gland, and increase the risk of thyroidcancer, particularly in children.


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The ingestion of potassium iodide is anestablished method to prevent the accumulation

of radioactive iodine in the thyroid.

Radioactive caesium has a half-life longer thanthat of radioactive iodine (up to 30 years) and

can stay in the environment for many years. Likeall radionuclides, exposure to radiation fromradioactive caesium can result in a increased riskof cancer.


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Food irradiation

Food irradiation means foods that areirradiated with radiation to kill any

bacteria that may be harmful to humanand also to preserve the food so that thefood can stay fresh for a longer time.

In this situation the food will not becomeradioactive.


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Whether the food is safe to eat or notremains debatable.


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THE END

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Radioactive Food Contamination