Posted by: Lone Wolf on: January 9, 2008
Coal Ash Is More Radioactive than Nuclear Waste
Over the past few decades, however, a series of studies has called these stereotypes into question. Among the surprising conclusions: the waste produced by coal plants is actually more radioactive than that generated by their nuclear counterparts. In fact, fly ash—a by-product from burning coal for power—contains up to 100 times more radiation than nuclear waste.
At issue is coal’s content of uranium and thorium, both radioactive elements. They occur in such trace amounts in natural, or “whole,” coal that they aren’t a problem. But when coal is burned into fly ash, uranium and thorium are concentrated at up to 10 times their original levels.
Fly ash uranium sometimes leaches into the soil and water surrounding a coal plant, affecting cropland and, in turn, food. People living within a “stack shadow”—the area within a half- to one-mile (0.8- to 1.6-kilometer) radius of a coal plant’s smokestacks—might then ingest small amounts of radiation. Fly ash is also disposed of in landfills and abandoned mines and quarries, posing a potential risk to people living around those areas.
In a 1978 paper for Science, J. P. McBride at Oak Ridge National Laboratory (ORNL) and his colleagues looked at the uranium and thorium content of fly ash from coal-fired power plants in Tennessee and Alabama. To answer the question of just how harmful leaching could be, the scientists estimated radiation exposure around the coal plants and compared it with exposure levels around boiling-water reactor and pressurized-water nuclear power plants.
The result: estimated radiation doses ingested by people living near the coal plants were equal to or higher than doses for people living around the nuclear facilities. At one extreme, the scientists estimated fly ash radiation in individuals’ bones at around 18 millirems (thousandths of a rem, a unit for measuring doses of ionizing radiation) a year. Doses for the two nuclear plants, by contrast, ranged from between three and six millirems for the same period. And when all food was grown in the area, radiation doses were 50 to 200 percent higher around the coal plants.
McBride and his co-authors estimated that individuals living near coal-fired installations are exposed to a maximum of 1.9 millirems of fly ash radiation yearly. To put these numbers in perspective, the average person encounters 360 millirems of annual “background radiation” from natural and man-made sources, including substances in Earth’s crust, cosmic rays, residue from nuclear tests and smoke detectors.
Dana Christensen, associate lab director for energy and engineering at ORNL, says that health risks from radiation in coal by-products are low. “Other risks like being hit by lightning,” he adds, “are three or four times greater than radiation-induced health effects from coal plants.” And McBride and his co-authors emphasize that other products of coal power, like emissions of acid rain–producing sulfur dioxide and smog-forming nitrous oxide, pose greater health risks than radiation.
The U.S. Geological Survey (USGS) maintains an online database of fly ash–based uranium content for sites across the U.S. In most areas, the ash contains less uranium than some common rocks. In Tennessee’s Chattanooga shale, for example, there is more uranium in phosphate rock.
And people are against nuclear power but not coal?
Today we have a real problem with pollution and global warming allot of it coming from coal fueled power plants nuclear power would go a long way in salving allot of those problems but because its nuclear people fear it.
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