Large Fierce Mammal

Yesterday’s article, Bullshit Alert – Since 11 March 2011, If You’ve Ever Even Heard of Japan, You’ve Been Exposed, introduced this and the article that follows, and explained my motivation for writing both. If you haven’t yet read my intro, please go and do so now before coming back here and moving forward.

Media coverage of the recent nuclear reactor explosions and linked disasters in Japan has not taken the science of the situation with anything approaching the degree of seriousness it deserves. My own take on this is that, as usual, ratings aren’t built on truth – they’re built on hype and tension so people keep watching for the latest update.

While all this is going on, an atmosphere of apprehension builds, even among people who have nothing to fear from the situation. Why? For the usual reason – fear of the unknown.

Born in 1957 Canada, I am a child of the cold war. Sadly, born in 1982 Poland, so is Mrs. LFM. The LFM archives still contain a copy of that Canadian Government classic and number one title in the Blueprint For Survival series, Your Basement Fallout Shelter. Our copy is the one ordered by my parents back in the day, in the wake of the Cuban Missile Crisis, and quietly pored over through many a long night, as they agonized over how to balance the burden of raising a family against that of building and stocking something that might represent the critical difference between life and death.

The shelter never got built, but years later I discovered that booklet in an envelope with still more documentation of similar ilk, and asked my father about it. By the time that conversation took place, I had developed a voracious interest in science – most particularly physics, and military history, from all of which I had come to understand the concepts of nuclear fission and nuclear fusion. I tried to explain the concepts to my father, but by this time he had spent far too many years marinating in the belief that it was all so very far beyond him. Bullshit.

Nuclear reactor accidents are not common, but with the expansion of populations in the world will come a drive to increase the number of nuclear power plants in service. The risk increases as these come to be built more and more often in so called “developing countries” where exploding birth rates drive the value of an individual human life below the level of esteem we in the west make a pretense of  demanding. Knowledge is power, and your government neither can nor will save you and that which you treasure. The science of understanding the effects of anything from a nuclear reactor accident to a hospital x-ray is completely within the grasp of the average person. All that having been said, let’s wade in.

First off, clear your mind of any thought that “radiation” and “radioactive” are the same thing. Let’s define the word “radiation”. Radiation is not a thing, it’s a process, and one of three ways that energy gets from one place to another (the other two being conduction and convection, neither of which apply to the topic under discussion). When energy is transported by radiation, particles or waves travel through a medium (like air, glass, or any other material that is more or less transparent to the energy) or space. This means that there is a source that is radiating these particles or waves, and as they travel out from the source they either pass through or are absorbed by open space or matter along the way. To put it simply, energy is radiated by a source, travels in a straight line at the speed of light, and will attempt to pass through anything in its path. This travelling energy is radiation, whether it comes from an exposed nuclear reactor core or a beeswax candle. It is referred to as energy again when it interacts with matter – clear air, a glass prism, a lead ball, a human body – where it may be completely unaffected, become deflected onto a different path, or be absorbed entirely. Far from being something sinister and mysterious, radiation is absolutely essential to life on Earth. If you go out today and feel warmed by the Sun, it’s because your skin and clothing are absorbing energy delivered by the process of radiation. When you heat your dinner in a microwave oven, it heats because the water molecules in the food are absorbing energy delivered by the process of radiation. When your dentist x-rays your teeth, the image he sees is possible because x-rays are delivered by the process of radiation, fired in a brief burst through your head, and are absorbed differently by your soft and bony tissues before they strike the imaging film where they produce a visible image because the intensity of x-ray radiation striking the film is greater where they passed through soft tissue and lesser where they passed through denser tissue, which simply casts more of a shadow. We see the world around us because visible radiation bounces off of objects in our field of view and into our eyes where its energy is absorbed and reacted to by the cells of our retinas. Radiation, then, is not a boogy man. Even though it can be the process by which energy lethal to living organisms is delivered, it is also the means by which such benign forms of energy as the light from our lamps and the radio signal from our favourite music station gets delivered. Radiation is a process that we are exposed to and use, indeed exploit, every day.

For analytical purposes, it is sometimes more convenient to treat energy travelling by radiation as a wave and at other times as a particle. To get a grasp on why, we will look at the frequency spectrum.

We all know from school science class that the spectrum is what we see when sunlight passes through a glass prism. White light is split into its component colours and ends up a beautiful display on the wall, always projected in the same order that can easily be remembered by the name of the fictional professor, Roy G. Biv. The order is Red, Orange, Yellow, Green, Blue, Indigo, and Violet. The same effect is at work when sunlight passing through airborne water droplets blesses our eyes with a rainbow. We won’t step off the path into how this happens. My point is to illustrate that the visible energy radiated by the sun, which we call light, consists, in fact, of seven distinct levels of energy – the visible spectrum.

But this is only a fraction of the big picture because it doesn’t end there. When you tune your car radio, you are causing it to become receptive to specific “frequencies” of radiated energy. We use that term as part of everyday speech without really thinking about it, and hear it spoken when announcers say things like, “104.5 on your FM dial!”. The news flash here is that radio energy is part of the spectrum too. Not the visible part, but we can certainly detect it and put it to work, as evidenced by the number of cellular phones around. When wrapping your mind around the concept of frequency and waves, think about waves lapping on a beach. They may arrive slowly, languidly, and 30 seconds apart, or they may be more energetic and wash in at 5 second intervals because a boat just passed by. Lower frequency versus higher frequency.

The visible spectrum is part of the all encompassing electromagnetic spectrum which identifies all frequencies of energy, from lowest to highest. To understand this, let’s take the visible spectrum chart here as our guide. The colours presented run from the lowest wavelength, and therefore the least energetic on the left – red, and progress to the highest wavelength and therefore most energetic on the right – violet. If we look at these energy levels as particles instead of waves that are either slower or faster to arrive on the beach, think of a little machine gun firing tiny bullets. The red bullets hit the target at a slower rate than the violet ones that hit with greater frequency.

If you’ve ever set out to cultivate a sun tan, or worse yet had a sun burn, you know about the effects of ultraviolet light. Sunglasses are sold with a label of 100% UV protection stuck to the lens for a reason. Well, UV is part of the spectrum too, just not the part we humans can see. It’s called ULTRA-violet because its energy level and frequency lies BEYOND violet, which would put it off the right hand margin of our visible spectrum chart. Being invisible doesn’t make its effects any less real, and its energy level even in this minor league within the spectrum, is something we all know is only to be ignored at our peril.

Similarly, we have infrared – INFRA-red meaning BELOW red. This means that its energy level and frequency put it off the left hand margin of our visible spectrum chart. As with ultraviolet, infrared cannot be seen by the unaided human eye, but it can be detected by other senses as heat. A camp fire warms you because it is radiating energy in the infrared frequency range. When this energy is absorbed by your skin it is perceived as heat. As with ultraviolet, the effects of exposure can range from wonderful to catastrophic, depending on two things – intensity and exposure.

Here’s a practical example of what I mean. It’s high noon on a sunny August day with not a cloud in the sky. One person goes outside and exposes their unprotected bare skin to the direct rays of the sun for a period of 5 minutes. A second does the same for 15 minutes, while a third does so for 30 minutes. At the end, each person was exposed to the same radiation intensity, but the one with the longest interval of exposure will experience the greatest effect and will most likely experience sun burn.

Now, let’s say we send one person out under the same conditions, and use a magnifying glass to focus sunlight on a small area of their skin. In mere seconds, if it takes that long, our unhappy subject will experience searing pain and blistering tissue damage. In this case, even brief exposure can have massive effects because the intensity of radiation is so high.

Let’s refer to our chart of the electromagnetic spectrum. Ignore the numbers on the chart. For purposes of our discussion here, only the labels representing the type of radiation (radio through visible on up to gamma rays) and the wave diagram matter. Note that going from left to right, waves start out more widely spaced, and become progressively closer together as we move upward in frequency and therefore higher energy level. As we move from left to right – that is, from lower to higher energy – in the electromagnetic spectrum, we find two distinct types of radiation – non-ionizing and ionizing. The line between the two is found when the energy delivered by the radiation is sufficient to strip electrons from atoms or molecules (I’ll explain that in a minute), rendering them positively charged. This process is called ionization, and the electrically charged atoms created by it are called ions. The radiation associated with what are referred to as radioactive materials – those used in nuclear reactors – is ionizing radiation. The same rules of measurement apply to all types of radiation, and while ionizing radiation presents a powerful risk of damage to living tissue, the rules of intensity and exposure still apply. Also remember, as we saw in our sun burn experiment, even non-ionizing radiation can be harmful if treated with a lack of understanding and respect.

From here on in, we’re going to focus our attention exclusively on ionizing radiation (the x-ray and gamma ray portion of the electromagnetic spectrum) because understanding the creation and effects of energy at this level is essential to grasping the health effects of exposure.

Purists will say that what follows is a gross oversimplification of atomic structure, but since my purpose here is to debunk radiation as it has come to be misrepresented in  popular culture, and I am only interested in its effects on living things like people, no more complication is necessary.

All matter, including you and me, is made of atoms. The average atom normally consists of one or more of the three basic “sub-atomic” particles – the neutron, proton, and electron. The way an atom works is shown in our animated diagram. In the center we have the nucleus which is made up of one or more neutrons which have no electrical charge, and one or more protons which have a positive electrical charge. Whizzing around the nucleus in tight orbit are negatively charged electrons. In a stable atom, the number of electrons equals the number of protons, so their mutual positive and negative charges cancel one another out leaving the entire atom in balance with no net electrical charge at all. Atoms can also combine to form more complex structures called molecules, one of which is DNA, the molecule that is the blueprint for every living thing on Earth.

Now let’s focus on thinking of radiation as a stream of particles instead of waves – remember my machine gun example earlier? Ionizing radiation has sufficient energy to strip electrons from their safe little orbits by simply blowing them away. The end result is a loss of electrical balance in the atom because there are no longer enough negative electrons to counterbalance the positive protons in the nucleus. The atom is now positively charged, out of balance, and is called an ion.

When living cells are exposed to ionizing radiation, this phenomenon can result in the creation of unstable atoms or molecules that are highly chemically reactive, with resultant damage to vital molecular structures like DNA. When this occurs, the organism’s ability to repair itself and develop new, healthy cells can become impaired resulting in autoimmune disorders and cancer.

Acute Radiation Syndrome (ARS), formerly called Radiation Sickness or Radiation Poisoning, results from exposure to ionizing radiation. Even relatively low levels of exposure can produce gastrointestinal symptoms like nausea and vomiting, while more extensive exposures can present as lowered blood cell count and neurological damage. A sufficiently large dose can lead to death within days. It must be understood that some of the people working right now to clean up the nuclear disaster sites in Japan are doing so in the full knowledge that they are committing suicide.

So if you’ve stayed with me this far, I’m going to bring it home for you. You can think of any form of radiation as the beam from a flashlight. It either hits you or it doesn’t. If it hits you square in the eye from close range it’ll have a big effect when it temporarily blinds you. If it hits you from a mile away, it’s a non-issue. Radioactive material like the Uranium in a Japanese nuclear reactor emits radiation in the high end of the electromagnetic spectrum, but it radiates it no differently than a white hot coal radiates heat and light. Get too close and it’ll burn you. Step back far enough and you can still see the glow so you’re still receiving some level of radiation from it, but you can no longer feel the heat. Get far enough away, or step behind a brick wall and you can’t detect it at all. This is the risk posed by being in close proximity to a highly concentrated source of ionizing radiation – a source that is referred to as radioactive. Tissue destruction occurs through simple proximity as living cells are irradiated and damaged on an atomic level. As we move further out from the the source however, radiation intensity rapidly diminishes to the point where it can no longer be detected. No wind, no matter how strong, can “blow” radiation anywhere, any more than it can bend the beam from a flashlight.

Press coverage of “released radiation” is misleading because radiation can only shine out from its source. What they are really referring to is particles of matter that are themselves radioactive, becoming air or waterborne, and making their way onto inhabited areas or into food and water supplies. If you’ve ever seen a major fire, you know how high, far, and wide the heat plume can carry the ash. In some cases, particularly with forest fires, new burns can be ignited by coals carried upward on the plume and later dropped sometimes miles away. An unbridled reactor core can generate heat that would make a forest fire pale in comparison, and as with any physical, non-nuclear ignition comes production of gases and particles. The problem with these is that they are, themselves, radioactive.

Particles settle to the surface of land or water eventually. Gases may disperse, but if they are vapours they will condense after cooling and likewise settle. Areas downwind of a burning reactor are evacuated because radioactive material is released, not radiation itself. This is an important distinction. Exposing water to gamma radiation will kill any living thing in it, but the water will not become radioactive – we routinely purify well water by running it through a source of intense ultraviolet (UV) radiation, but drinking it doesn’t cause sun burn. Mix radioactive dust into the water though, and you have a brew that is unsafe to drink because ingestion of the particles, even in solution, will irradiate the consumer from the inside. A can of beans coated in radioactive dust, once cleaned, and I mean cleaned, will be safe to eat. As with all sources of ionizing radiation, the best protection is to get as far away from it as possible, something that is made a lot easier when you know your enemy and how it operates.

So, in the end, it’s pollutants released and dispersed by a nuclear disaster site that people living downwind of it have to deal with, and while these may represent a threat to health and safety and should be treated as highly toxic crap, they are not magical. We all know about the way pollen gets all over everything in the spring time, and if you’ve spent any time walking around in the business center of a major city, you’re familiar with the eye irritation, the smell, and even the taste of car, truck, and bus exhaust. A pollutant is a pollutant. It’s most often either going to arrive as particles, vapour, or gas suspended in air or water, be encountered as solid particles or droplets condensed from vapour that have coated exposed surfaces as with any other dust, dirt, or mist, and as dissolved and therefore invisible chemicals in water and other liquids that have been open to the air. Solid, liquid, or gas, radioactive pollutants can best be understood as consisting of a multitude of minuscule emitters of dangerously high energy, but the size of each, and the kinds of radioactive materials of which they’re made, limits the amount of radiation you will absorb for a given period of exposure because some reactor produced isotopes are more energetic than others, and unlike a large radiated energy source like a reactor core itself, the pollutant particles it releases during an accident are more dispersed. From this it’s clear that getting away from the actual disaster site is a first priority, but for most people affected, getting out of the path of everything pouring out of it runs a close second. All of this is why we see workers doing cleanup at a nuclear disaster site being decontaminated at the end of a shift. Those fancy suits they wear don’t stop energy from radiation emitted by the reactor core and its byproducts, but they do prevent direct contact with and ingestion of the dust, dirt, vapour, and gases that are inevitably encountered on any accident cleanup site. The contaminants are therefore rinsed off with appropriate solvents before workers break the seal on their suits.

That’s it for part two of three. Please feel free to post questions or comments. Your concerns will not be ignored.