The Appalling Radiation Perii

The Newsletter, vol. 2 no. 53, 17 May 1958 · scan page 2

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OUTSTANDING fact about our knowledge of the dangers of fall-out is our abysmal ignorance. An article in the periodical Science recently revealed that new studies have shown fatal illnesses to result at less than one half the dose of radium believed dangerous since 1948.

These illnesses can take as much as forty years to appear, though most of them turn up within twenty years. Ten years has brought a halving of the danger level.

Who dare say what fifty years will bring?

Add to this the fact the danger levels for all other radioactive substances were set by comparison with radium, because radium is the only one which has been in use for a long time ——a comparison made-by the very simplest physical effects IN DRY AIR, which may turn out quite unrealistic for biological dangers—and one sees that all talk of safety at present levels is folly.

The people who set the safety limits were men with too little knowledge—great scholars trying to do the impossible because the facts are not known.

They realized they did not know everything, so they tock a tenth of what was known to be dangerous and called it safe. But there are good reasons why not a tenth, nor a hundredth, nor a thousandth may be safe—or any amount at all.

But nebody can tell They allowed ten times as much strontium-90 as radium, because they knew it did ten times less damage—in dry air. They may be right. Nobody can tell.

The two important kinds of radiation from fall-out do harm in different ways. Gamma rays, like all other X-rays, can pass right through a human. body, but some of them are stopped on the way, — ° Every one which is stopped, or turned aside from its path, splits off an electron from some atom or other. These electrons move very fast, and are just like those other fast electrons called beta rays.

So beta and gamma rays act in a similar way. Except that gamma rays act all over the body, throwing out electrons everywhere. Beta rays and electrons cannot move very far in flesh—two or three tenths of an inch at the most.

Gamma rays do damage everywhere, very little more in one place than another, beta rays only near the place they start from. ‘ Actually nearly all the damage is done where they stop. And beta rays do not start all over the place—they are found chiefly near the most sensitive vital parts of the body. That makes them far more dangerous than gamma rays.

For instance, there is a lot of strontium-90 in fall-out, and quite a lot of strontium-89, Both these go into bones. Go just This is the second of two special articles by our scientific correspondent on the scientific and military aspects I DLL ALAA PL of the hydrogen bomb.

The series will be continued with an article by our medical correspondent designed to give workers as simply By J. H. BRADLEY :

the grass in the fields. Cows which, like all mothers, feed their offspring milk rich in calcium, and the strontium which goes with it.

That is why it is not true that all the fall-out around us is only like living a few hundred feet higher up a hill, or like living in Scots granite houses. We do not live with our sensitive bone marrow getting most of the damage from cosmic rays or granite.

But don’t worry—there is a charming term to describe strontium-90. It is measured by Sunshine Units. Moonshine ~~ would be a better word.

There will be a lot more ‘sunshine’ yet, and moonshine too. By December 1955 activities as high as 240 millicuries per square mile had been found to fail in one day from those ‘tactical’ bombs tested in Nevada.