Special issues arise with certain categories of hazardous wastes. For example, nuclear waste presents serious political and technical problems for which there are few satisfactory answers. Some low-level radioactive wastes are produced by the use of relatively small amounts of radioactive materials for electricity generation, medical diagnosis and treatment, biomedical and pharmaceutical research, and some forms of manufacturing. Also, the end of the Cold War— the period of ideological tension between the United States and the Soviet Union from 1945 to 1991—left both countries with highlevel radioactive waste from decommissioned nuclear weapons. However, most high-level radioactive wastes are created when uranium is mined for use as nuclear fuel, or later when nuclear power plants produce spent fuel that is highly radioactive.
Mining, for example, separates relatively small amounts of uranium ore from vast layers of impervious rock, creating tailings —a liquid, radioactive mud that can decay into radium-226, which in turn decays into radon gas, a potent carcinogen. Once released by the mining process, these tailings can pollute waterways or drift into the air and can persist in the environment for up to one hundred thousand years. Many uranium mining sites have become environmental wastelands, unfit for human habitation. Some abandoned uranium mines are located in Australia, while others can be found in the southwestern United States. Most of the uranium wastelands, however, are located in the poor African countries of Namibia and Niger, where they continue to cause devastating health problems for local peoples.
Nuclear reactors, used to produce electricity, also create tons of radioactive nuclear wastes. Reactors must be closed down every year or so to replace about one-third of their uranium fuel rods. Each time, this creates about 30 tons (27 metric tons) of spent fuel made up of plutonium, fission products, and uranium —all of which emit lethal radiation. In fact, as University of Rochester engineer Ezra Gold notes, "The toxicity of plutonium is among the highest of any element known."31 This material is stored in water-cooled ponds at the reactor site for at least fifteen days, allowing the radioactivity to drop significantly. Afterward, however, the spent fuel remains a dangerous, slowly decaying radioactive material for thousands of years.
Low-level radioactive wastes are fairly easily disposed of, usually by encapsulating them in heavy concrete containers or vaults, which are then buried deep underground. These wastes lose most of their radioactive risks after a few decades. So far, however, no one has found a viable, permanent disposal solution for highlevel radioactive wastes that stay radioactive virtually forever.
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