About radiation, part 1: Acute Radiation Syndrome (ARS)

It's all around us, its everywhere - just like Kraftwerk points out in their song Radioaktivity: 

"Radioactivity - it's in the air for you and me"

 ...and this is true. Every day we're exposed to radiation. Living on Earth, the magnetic field of the planet protects us from dangerous gamma radiation from the space that surrounds us all, but even down here, we're still exposed to radiation from various sources: Radiation also comes from the bedrock, our TV sets, computers and a lot of other utilities and devices we have invented and even from ourselves. Like all living creatures on this planet, we radiate.

However, the gathering term of "radiation" is generally mistaken for ionizing radiation, which is a term for the kind of radiation that has the characteristics of knocking electrons from their atoms, which turns the atoms into ions. Ionizing radiation, to put it shortly, may be electromagnetic radiation (gamma, roentgen and ultraviolet radiation) or particle radiation which is constituted by atoms or parts of atoms moving in a "flow". Examples of this is alpha, beta and neutron radiation. 

Chernobyl liquidator in 1986. Photo from Belarus.com

But what happens when the human body is exposed to ionizing radiation? 

As the energy of the [ionzing] radiation reaches the body, electrically charged elements are formed, and these are the very ions. They trigger the culturing of new, strange elements in the tissue which may cause irreparable damage to the cells. The constitution of hydrogen peroxide easily adapts to the molecules of the human body and  is known to alter their chemical structures.

Still to this day, we know more of acute radioation syndrome (ARS) than we may be able to determine happens to the human body if exposed to relatively small increased levels of ionizing radiation during a longer time span. It's recorded that such a thing increases the risk of developing cancer, but there are still many questions that need to be answered within that area, as it's also been proven that people living on sites where the bedrock emit higher levels of radiation, are generally healthier than their equivalents in places where the bedrock is less radioactive, so it goes without saying that we still have a lot to learn about radiation.




Acute Radiation Syndrome

Radiation, nowadays, is measured accoring to the Sievert (Sv) units, but there's another unit for measuring how much ionizing radiation the human body has absorbed, and this is measured in so called Grays (Gy). 1 Gy is equivalent to 1 Sv The threshold of ARS is defined between 0,5 - 1,0 Gy - having exceeded this limit, the well known symptoms of nausea, vertigo and vomiting occur.  If being exposed to what is regarded as a mild dose (1-2 Gy) you may expect symptoms of nausea and vomiting withing six hours, and the later effects, such as weakness and fatique,  will occur approximately three to five weeks later. 

 If having absorbed more than 6 Gy, most symptoms, nausea, headache, vomiting, fever and diarrhea will occur within a matter of hours, and then follows the so called latent period. Also at mild exposure, there is a latent period followed by mild leukopenia (Leukopenia means a decrease of white blood cells in the human body, which increases the risk of infections.) fatique and weakness, but the mortality is low: Regardless if being treated or not, the mortality is lower than 5% and those who die from mild absorption are especially old individuals, or individuals of already poor health, but at absorption over 6 Gy, death is almost certain if the individiual is not treated and even if treated, the mortality is between 50-100%. 

Workers on the roof or reactor block 4, 1986. Photo: guardian.co.uk

The higher the absorption, the shorter is the latent period and absorbing over 8 Gy, the latent period will be absent and death follows within 2-14 days. 


Even though no one seem to be able to determine or tell for sure, about the levels of radiation that some of the Chernobyl liquidators were exposed to, we can almost be sure of that they absorbed far over 8 Gy (some firefighters were estimated to having been exposed to approximately 750 Roentgen per hour, but the true numbers should exceed this. 750 R = 7.5 Sv = 7.5 Gy), why they died very shortly after the exposure, over a short time span having suffered multiple severe ARS symptoms.


ARS symptoms at absorption over 8 Gy are: Nausea and vomiting, diarrhea, intense headache, high fever, electrolyte disturbance, shock and disturbance of the central nervous system.