Chernobyl

Chapter 25

Within large continents, air generally moves across the surface of the Earth from west to east, with a slight curve toward the poles. For that reason, the weather in Chicago usually comes from somewhere in California, and Moscow gets a large part of its weather from Spain or France. At any particular place or time, however, the winds can be quite fickle. If the Soviet air masses had been moving in the prevailing direction in April and May of 1986, the gases from the Chernobyl explosion would have been carried out over Siberia and the Pacific. They weren't. First they moved north. Then east. Then everywhere.

The first stops for the wandering witches' brew from Chernobyl were Poland and eastern Scandinavia. The invisible cloud was greeted with confusion and panic. In Poland, the official press was reassuring. The underground press, which was what the Polish people read to find out what is going on, was not. So Polish pharmacies were sold out of potassium iodide overnight, for the scariest ingredient in the cloud was its radioactive iodine-131. The trouble with the radioactive iodine was that every human being has a thyroid gland, and every thyroid gland has an insatiable appetite for iodine. If the iodine happens to be the radioactive isotope, the gland swallows it anyway. There the iodine stays, ceaselessly bombarding the victim from within with its radiation. Cancer of the thyroid is one of the commonest consequences of exposure to radioactive leaks.

Before long the winds took Chernobyl's gases south and east, to blanket most of the European continent, but by then iodine-131 was no longer the greatest fear. Radio-iodine has at least one virtue. It is short-lived. In only eight days half of it decays into something else. Two other isotopes were by then more worrisome, and they were xenon-133, a gas, and cesium-137, normally a solid. (But, like the iodine, volatile enough so that large amounts went up with Chernobyl's smoke and remained in its cloud as finely divided particles.) The xenon, being a gas, is particularly troublesome. Rain won't wash it out of the air; it is there to be breathed until it, too, decays. The cesium is even worse. It takes thirty years for half of it to decay. When it finally falls to the ground, it remains in the soil and water for a long, long time.

Of course, even after the thirty years of xenon's half-life have passed, not all of it will be gone. Half will still be there; that's what "half-life" means. If one were to follow the history of one small patch of someone's backyard onto which one million atoms of radioactive cesium from Chernobyl had fallen, by the year 2016 five hundred thousand atoms would still be there. There would still be over sixty thousand radioactive atoms of the stuff by the beginning of the twenty-second century. Sooner or later, of course, it would all be gone from that little patch, and the last of those million atoms would have turned into something else. That should happen somewhere around six centuries from now.

When the little particles of radioactive cesium finally settle out from the sky, they cling to whatever they land on. Some of them have landed on farms of lettuce and spinach (which people eat), or on grassy pastures (which cows eat, and turn into cesium-bearing milk for people).

So all over Europe governments ordered, or people simply decided on their own, that fresh milk and leafy vegetables should be removed from the daily diet. That was nasty for parents of small children. It was even worse for farmers. Exports of any of those things from Eastern Europe were refused at the borders. When the cloud reached as far south as Italy, the authorities banned the sale of even locally grown leafy vegetables and Italian farmers, broken-hearted, saw their crops dumped into fields to rot.