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2. Natural and man-made threats: scientific view
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2. NATURAL AND MAN-MADE THREATS: SCIENTIFIC VIEW
9. Read the text and answer the questions below it.
Nuclear Radiation Can Affect Our Health — For Better or Worse
You might not know exactly how to describe it, but chances are good that you know the word radiation can have two very different connotations. On the one hand, radiation exposure was one of the most feared consequences after an earthquake and a tsunami dam-sequence damaged a nuclear reactor in Japan earlier this year. On the other hand, radiation may have helped someone you know fight a disease such as cancer. How can one word have such different meanings?
All Around Us
Radioactive materials give off invisible atomic particles or energy called nuclear radiation. “Radiation is always around us, ” notes Dr. Ritsuko Komaki, a professor of radiation oncology at the MD Anderson Cancer Center in Houston. Very high exposures to nuclear radiation can cause sickness and, in the worst cases, death. But most radiation around us isn’t something to worry about. Some normal amounts of nuclear radiation come from the sun, along with the sun’s heat, visible light, ultraviolet rays, and more. Tiny bits of nuclear radiation are in soil too. “Usually it’s a very low dose, and it’s not harmful, ” says Komaki. Activities such as mountain climbing or taking a long airplane ride expose you to slightly more radiation - because you’re closer to the sun. Experts generally don’t worry about those exposures either.
Nuclear reactors, such as those at the Fukushima Daiichi plant in Japan that was damaged by the 2011 earthquake and tsunami, split uranium atoms. That action releases energy. The energy is used to boil water, which in turn creates steam that moves turbines that make electricity. When everything works, the process doesn’t pollute the air or water. Nuclear plants’ fuel and certain wastes, however, are radioactive. When emergency measures failed at Fukushima, explosions and fires released radioactivity into the environment. Cleanup will take years. Meanwhile, the accident has heightened fears about radiation.
Radiation’s Risks
After a nuclear accident, radiation levels in the area of the nuclear plant can be thousands of times higher than they were before. Very high exposures cause acute radiation syndrome. Symptoms can range “from not feeling right to seizures and even loss of consciousness and death, ” says Dr. David Weinstock at Boston’s Dana-Farber Cancer Institute. In addition to making people sick right away, too much radiation can damage cells and raise a person’s risk of developing cancer later in life. In 1986, a nuclear power plant exploded in Chernobyl, Ukraine. Years later, thyroid cancer rates rose among young adults nearby. (The thyroid gland helps control the body’s energy levels and other functions. ) The young people had grown up drinking milk from cows that ate contaminated grass.
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Authorities are checking radiation levels in various foods and water to prevent similar problems in Japan. The U. S. Food and Drug Administration (FDA) is also monitoring foods coming from Japan to the United States. While scientists found slightly higher radiation on the West Coast after the Fukushima accident, amounts were way below danger levels. “The Fukushima event really poses no risk to people in the United States, ” says Weinstock.
On the Plus Side
Nuclear radiation can help us get — and stay — healthy too. A special type of radiation is used to treat some meats, fruits, and vegetables to kill bacteria that can make people sick, for instance. In the same way that nuclear radiation’s energy can kill some of the body’s cells, it can also be used to kill cancerous tumors. “We are just targeting the cancer cells and protecting normal tissue surrounding the cancer, ” explains Komaki, who primarily researches lung cancer. According to the National Cancer Institute, approximately half of all cancer patients receive some form of radiation therapy as part of their treatment.
Some forms of nuclear radiation can help doctors track down health problems in the first place. Torso X-rays and computed tomography (CT) scans use nuclear radiation to see inside the body. The benefits from being able to find health problems generally outweigh any tiny risks from exposure to radiation, but some accidents have happened. As a result, the FDA wants medical scanning equipment to have even more safeguards than it does now. Either way, experts say it’s a good idea to limit your exposure to nuclear radiation even when it’s part of a medical test. Always ask why any scan is necessary, especially if you think you have had that same test recently. “If there’s no justifiable reason for the extra radiation exposure, then don’t let yourself be exposed” if you can help it, says Kelly Classic, a health physicist at Minnesota’s Mayo Clinic and spokesperson for the Health Physics Society. Scientists and health experts around the globe continue to study nuclear radiation. They hope to harness its powerful benefits to continue to help people. When it’s used intentionally, radiation can be a boon to human health. “There are hundreds of thousands to millions of people who are alive today because we’ve harnessed the power of radiation, ” says Weinstock.
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