NBC Weapons: Death By Inches




September 2, 2009: Radiation, from nuclear weapons, terrorist "dirty bombs" (explosives used to spread radioactive material) or malfunctioning (from terrorist activity or otherwise) nuclear power plants, is greatly feared. Yet we are constantly exposed to potentially harmful amounts of radiation. That's because radiation is a naturally occurring phenomena. We are all exposed, on the average, to at least 160 mrem per year. A mrem (milliroentgen equivalent to man) is a standard measure for radiation absorbed by humans. This normal exposure causes problems. For every 100 million people, that comes down to; 4100 fatal cancers, 2500 nonfatal cancers, 4600 genetic defects (not all of which are obvious). For every additional mrem per person per year, the above rates will increase .67 percent (75 cancers and genetic defects per 100 million people).

About a fifth of the average natural radiation (30 mrem) is received from the sun, which is an ongoing thermonuclear explosion. Spend more time in the sun, and you get more radiation (and maybe even skin cancer, how's that for karma). About 25 mrem comes from proximity to building materials, stone being the most radioactive. Living inside a stone building will add 50 mrem a year. The things we eat and drink add another 40 mrem. The remaining 65 mrem come from such manmade sources as: X-rays and medical treatments (50 mrem, but rapidly rising), air travel (1 mrem per 1,500 miles), watching TV (1 mrem if you watch 6.67 hours a day, the average American watches some 2,600 hours a year), fallout from previous atmospheric nuclear weapons tests (4 mrem) and the remainder from various consumer products. Spending all your time next to a nuclear power plant adds 5 mrem, less than 1 mrem if you live 2 kilometers away and zero mrem if you are 8 or more kilometers distant. If a nuclear power plant does blow, like Chernobyl, you get doses similar to those received from a nuclear bomb. Then there is radon. This is a gas produced from the natural breakdown of uranium in the earth. In many parts of the world, radon seeps into houses and concentrates to the point where it gives the inhabitants an average of 200 mrem per year. The problem with radon is that its concentration varies from one area to another. In a few places, inhabitants of well insulated houses sitting atop large uranium deposits can receive more than the safety limit of 5,000 mrem per year. The key factor here is modern, well insulated housing (which allows the radon to accumulate. People living in more primitive shelter have little to fear from radon gas.

The most rapidly growing source of radiation is medical procedures. People are getting more X-Rays and CT scans. The latter really pump out the mrem (1,200 for an abdomen scan, 760 for the chest). PET scans give you 600 mrem. Using radiation to treat cancer can deliver even higher levels, while other radiation treatments tend to deliver much less. Nevertheless, the increased use of radiation based medical treatments in some industrialized countries, has nearly doubled individual mrem exposure. However, this medical use tends to create a net reduction in deaths because of disease being caught early and cured.

Nuclear weapons are noted for longer-lasting radioactivity as well as instant blast and heat damage. The unit of radiation for nuclear weapons is the rad, which is equal, for our purposes, to 1,000 mrem. Radiation kills over time. If enough radiation is received in a short period, it can kill immediately or within days, weeks or months, depending on the dose. Six hundred or more rads can kill within hours and disable immediately; 500 to 600 rads are always fatal, often within days. About 50 percent will die with 200 to 500 rads. At levels of 100 to 200 rads five percent will die, although long term effects (cancer) become a major factor. A 50 rad dose will induce nearly two percent early deaths from cancer and genetic defects.

These high levels of radiation exist very briefly, seconds in some cases. In the area closest to a ground level explosion, which is preferred for destroying missile silos, there will be hot spots of intense, longer lasting radiation. One year after the explosion of a one megaton bomb on the surface, the 100 rad zone will be a circular area of 46 square kilometers (7.6 kilometers in diameter). Nearly 4 percent of the population in that area will die prematurely. Many others will suffer radiation sickness. This area should be a forbidden zone, even though it will be teeming with vegetation and small animals. The point of highest radiation in this zone will be the explosion crater, 360 meters wide and 120 meters deep. The next zone as an average of 50 rads and covers 67 square kilometers (9 kilometers in diameter). There will not be as much radiation sickness, but two percent of inhabitants will die early. The 10 rad zone covers 300 square kilometers (20 kilometers in diameter.) This could be lived in, although there would be three or four early deaths per thousand population. Within a few years, even the crater will be under the 10 rad level. 

You can also forget about giant spiders and two-headed mutants. Insects are far more resistant to radiation than mammals. Mutations are generally either fatal or unnoticeable. Natural radiation has been responsible for more mutation than any nuclear war could ever produce.

While radiation may not be your friend, it is your constant companion.




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