National Geographic : 1970 Dec
testing to see what effect they'll have. If one or a combination of them should ever poison the nitrifying bacteria on a worldwide scale, the air would become unbreathable." Nuclear power-generating plants produce only small amounts of radioactive wastes. But hot wastes resulting from the produc tion of atomic weapons-that's another mat ter. Usually the material is encased in steel and-concrete tanks buried in clay, to keep radioactivity out of the ground water. "There are millions of gallons of the stuff in storage depots near Richland, Washington, and Aiken, South Carolina," Dr. Cole told me. "Some of it is so radioactive that it boils and must be artificially cooled." He rubbed his forehead wearily. "That's quite a legacy to leave our unborn genera tions. We'll have to tell them to keep close watch on the liquid, and to change the tanks when they begin to leak-and keep at it for the next six to ten centuries!" Atomic scientists are trying to avoid pass ing that legacy on. They have succeeded in solidifying some of the hot wastes for burial about 20 percent of the total, thus far. What about nuclear power plants? Do they pollute the air with radioactivity? I asked the question of Mr. Harlan K. Hoyt, superintend ent of Commonwealth Edison's Dresden Nu clear Power Station, 55 miles southwest of Chicago, Illinois. "Some radioactivity is present in our stack gases," Mr. Hoyt said. "But if you lived at the fence line downwind of that stack, you would absorb only one-twentieth as much radio activity in a year as you would get from one chest X-ray." But environmentalists worry about any in crease in atmospheric radioactivity, and note the growing number of nuclear power plants. When man takes something from his planet, they point out, there may be hidden costs involved. A town lures a new industry by allowing it to contaminate the local river. A jet speeds 150 people across the country, and cloud cover may increase imperceptibly. "We ecologists have a word for bargains Visual pollution: A jungle of distracting signs, compressed by a telephoto lens, dwarfs a lone bench-warmer on U. S. Route 1 in North Miami, Florida. Such on-premise ad vertising-not controlled by federal legisla tion-as well as billboards, utility poles, junkyards, and automobile graveyards, mar the roadsides of America.