|Quoting Jwenting (Reply 3):|
Worse, those ash deposits are radioactive.
Not all that much, but a lot of them are borderline for being nuclear waste rather than chemical waste and someone with the right facilities might be able to extract that radioactive material and make it into a dirty bomb.
Was a revelation when I found that out while working in a radiation lab during graduation work.
Wow. What to do, run around in small circles I guess.
Of course coal fired power stations put out more radioactivity that all except one nuclear power station ever has. Is it a problem, not really.
Sci Amer can manage this:
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.
If you want to avoid low level radiation probably moving NEAR a coal ash site is a good idea if you are currently living in much of Florida or are thinking of working in large number of agencies in central Washington - check for red granite walls and floors. Don't THINK of living in many states in the west.
The problem with uranium is not that it is radioactive - it has a half life of 4.46 billion years for the main isotope and 700 million years for U235 - but that it is poisonous. Some of the daughter elements from decay are much more radioactive, but the concentrations of these are small.
Most elements are below average crustal abundance in raw coal. Burning them gets the concentration up to about crustal average for most elements and above crustal average for a small proportion but mostly not much above. If there were many elements much above crustal average, the ash deposits would indeed be mined as a source of some less abundant elements. But alas ...................
For a discussion of trace elements in coal see
for a short review. The book concentrates attention on elements considered to be of environmental concern. Some of Swaines earlier publications provide information across the full spectrum of TEs in coals.
A fair proportion of coal ash is incorporated in various building materials these days, roads, houses, sidewalks. Best be alert to these hidden dangers NOT.
Many of the articles on U in coal ash are emerging from the nuclear industry. Hardly surprisingly after being panned over nuclear waste for half a century they are looking for other scapegoats. One article even manages to integrate all the U in coal ash from 1937 to date for the whole world. Gosh, that is scary!
Yes, if a dam retaining wall bursts that could be a problem. Other than that, leachate is the main problem, but before you get around to U and Th, try worrying about Hg, As, Cd and something else I am forgetting. Especially, worry about the mercury emissions that were permitted under the last administration, especially as I keep saying in Texas!!!!
[Edited 2009-06-14 01:09:59]