Mark Twain’s Cat & The Risk from Radioactive Materials | Nevada Technical Associates, Inc.

Mark Twain’s Cat & The Risk from Radioactive Materials

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Written by Robert Holloway

December, 1998.

When people learn that I work in the field of radiation protection, they often ask questions that reveal a great deal of concern about the risks associated with radioactive materials. This document is an attempt to address those concerns.

Have you ever noticed that many hotels do not have a 13th floor? Recently I checked the seating on several airlines to see if they too have omitted seats numbered 13. Although it is not universal, row 13 is missing on many airplanes. There is no real evidence to suggest that the 13th floor or row 13 on a plane is any less safe than any other floor or row. But because at least some of the public believes otherwise, the owners have made a concession to a belief that has no foundation in fact.

Although the analogy is not exact, many people have a fear of radiation that is often out of proportion to the amount of risk. I don’t mean to imply that there is no risk from radiation (it depends entirely on the circumstances) but that in many cases, the public’s perception of risk is greater than the actual risk.

A good example of cases where the perceived risk is greater than the actual risk is in the case of low-level radioactive waste disposal areas. Hospitals and research organizations use radioactive materials in various ways and the waste from these operations must be disposed of in some orderly and safe way. Proposals to start new low level waste sites usually meet with opposition, making it difficult to get rid of radioactive medical waste.

Are such disposal sites really dangerous? I don’t think so. When I worked for EPA one of the things that we were responsible for was to monitor the area around a low-level waste site in Nevada. The air in the vicinity of the site was normally entirely free of artificial radioactivity, although it did contain easily detectable amounts of natural radioactivity. The only exception was a tiny amount of tritium that was sometimes detected, just above the very low limit of detection. The amount was less than 1% of the amount of natural radioactivity normally present in the air from radon and radon decay products. A few hundred yards away from the site, I doubt if the tritium was even detectable. As with any hazardous material, the fact that the material is present is not the key issue. The key issue with respect to human health is the concentration of the hazardous material and whether or not there is possibility of it coming into close contact with humans. Analytical methods normally give us the ability to detect radioactive elements at a level far below the levels that are considered dangerous.

The low level waste site in Beatty, Nevada was closed to additional storage of nuclear waste. I am not sure of the reasons for closure, but I suspect that it was probably due to pressure or new laws of the state government. If that is the case, it is another example of irrational fear of radioactive materials based on perceived risk that does not exist in reality. Low level sites for radioactive waste have been the subject of much controversy throughout the country.

One convenient way of assessing the risk from radioactive materials is to compare the risk with the risk from naturally occurring radioactive materials. We are all exposed continuously to radiation from several natural sources, including cosmic rays, the radiation from natural elements in the soil and building materials, and even from naturally radioactive potassium in our bodies. When the risk of low-level waste sites is evaluated by this type of analysis, the sites can be shown to be harmless.

The regulatory agencies have rules designed to reduce our exposure from artificial sources so that the total dose from natural and artificial sources is only slightly more than from natural sources alone. The very tiny risk thus added from medical x-rays and other artificial sources is believed to be far less than the risks that we normally accept in every day life.

I like to use another example to illustrate risk and how it is often misunderstood. We have all heard that the element plutonium is the most toxic substance known to man. Although Plutonium can certainly be dangerous, even Plutonium is not exempt from the general rule that the poison is in the dose. If you have a lawn or even a few yards of dirt in your front yard, you are the owner of millions of atoms of plutonium. Almost every square yard on the face of the earth has detectable plutonium that was deposited there during the atmospheric weapons testing of the 60’s. Why is it not dangerous? A simple answer is that there is so little of it. The activity of of the plutonium is somewhat less that the naturally occurring radioactivity of uranium and thorium that is present naturally in the same ground. There is not much plutonium there, but it is not so difficult to measure and a radiochemist only needs two or three grams of the soil to obtain detectable amounts of plutonium. I don’t mean to imply that the plutonium would be present in dangerous amounts if its activity was greater than the naturally occurring activity, but using the natural level is a convenient way of making the point.

Those who oppose almost any use of radioactive materials fail to understand the difference between safe use of such materials and unsafe use. It reminds me of a story that Mark Twain told about the cat who sat on a hot stove lid. The cat got off the stove lid in a hurry and Mark Twain noted that the cat would never sit on a hot stove lid again – nor on a cold one either. Those who are fearfully concerned about such things as low-level radioactive waste are like the cat who avoids all stove lids, hot or cold.

The political institutions will finally make the decisions on low-level waste and other matters involving radioactivity. In the last few years, the influence of those who have unreasonable fears of radioactivity has often tipped the balance in favor of decisions that are based more on fear than rational thinking. The political institutions have yielded in much the same way that the owners of the hotels and airplanes have catered to the public in omitting the 13th floor and row 13 in airplanes. It costs nothing to leave out the number 13 from planes and hotel floors, but there is a cost to society from unreasonable fear of radioactive materials. It comes in the form of higher hospital bills and higher utility bills as consumers pay for millions and even billions of added costs related to nuclear waste disposal. Many of the professionals in nuclear related occupations are distressed by the misunderstanding of most of the public. The number of people qualified to assess risk is far fewer than the number of outspoken citizens who do not understand the risk.

As a final thought on the notion of accurately evaluating risk, ask yourself how many people do you know who died as the result of over exposure to radiation? Then ask yourself how many people do you know who have died in an automobile accident or from lung cancer? If several hundred people read this page, the odds are that few or none of them will know anyone who died from radiation related incidents but most will know several who died either from lung cancer or from an automobile accident. If all the people who are against all uses of radioactive materials would spend the same amount of energy working against drunk driving or smoking, they would no doubt save a thousand times as many lives.

Note: Dr. Robert Holloway was a radiochemist who worked for more than 15 years for the Environmental Protection Agency in the monitoring program in the vicinity of the Nevada Test Site. Dr. Holloway founded Nevada Technical Associates, Inc. in 1994. He passed away March, 2010.