Just read about a power company getting in trouble over their ash ponds leaking. It makes me wonder just how bad ash is pollution-wise. I know that ash from waste incineration is EXTREMELY toxic and that some places vitrify it to keep it out of the ground water. But a power company would no doubt be burning coal or oil. So I don’t know how bad that is. It seems to me that the volatile components would have been eliminated when it was burned, leaving behind mainly carbon. But that’s just a WAG.
Um. Carbon is the bit that you’re burning. It combines with oxygen and goes up the smoke stack. If you’ve got mainly carbon left when burning something, you’re doing it wrong.
Species of concern in coal ash are arsenic, mercury, lead, selenium and other heavy metals. The composition depends a lot on the coal origins.
I am in two minds to post links since most websites have either a right or a left agenda and are not strictly scientific.
Here are two links (one with a left agenda and one with a right)
http://www.psr.org/assets/pdfs/coal-ash-hazardous-to-human-health.pdf
https://www.ameren.com/-/media/Corporate-Site/Files/environment/EPRI-IsCoalAshToxic.pdf?la=en
The terms of art for this sort of thing are fly ash and bottom ash. Fly ash generally having the higher levels of contaminants. That shit can be quite nasty, as am77494 has said. Often nicely radioactive, too!
I am not sure I said that. I just said that there are heavy metals of concern maybe in concentrations above background levels - but as to its “nastiness” i.e. level of danger posed to humans/environment is a debate.
If nuclear radiation from waste is your concern (in addition to nuclear plants) - then phosphogypsum (a product of the Fertilizer industry) in Central Florida should be the biggest concern - especially the phosphogypsum washing into waters during hurricanes.
The agriculture lobby in the US is very strong - so it will probably never be discussed. If you want to do further research - you can start here :
- “…the marine-deposited phosphate ore from central Florida is highly radioactive,… there are about 1 billion tons of phosphogypsum stacked in 25 stacks in Florida”* - Phosphogypsum - Wikipedia
“Radium concentrations at phosphogypsum stacks range from 11 to 35 pCi/g.
Radon (Rn-222) can be found emanating from the surface of phosphogypsum stacks. Average radon fluxes range from 1.7 to 12 pCi/m2-sec and can be as high as 340 pCi/m2-sec…*” http://www.epa.gov/radiation/tenorm/fertilizer.html
You’re right, I apologise.
Better for me to say “can contain shit that can be quite nasty in high enough concentrations”.
Personally, radiation from gold mine dumps are a bigger (local) concern. For a given value of local, of course.
There are naturally occurring amounts of heavy metals and radioactive elements in coal. They are in fairly low concentrations, as you’d expect. When you burn the coal, the carbon gets burned off into carbon dioxide and a lot of other volatile substances burn off or evaporate as well. Since you removed most of the other stuff, the remaining ash now has much higher concentrations of heavy metals and radioactive elements and such.
People often like pointing out that the radiation levels outside of a coal plant are usually higher than the radiation levels outside of a nuke plant (see MrDibble’s link for example). While that is true and does bring up a good point, it also kinda implies that nuke power is categorically cleaner and ignores the huge problem of nuclear waste, for which we really don’t have a good solution yet. You also won’t ever see Chernobyl or Fukushima levels of radiation outside of a coal plant even under the worst of conditions.
Ash from a power plant isn’t anywhere near as dangerous as say a hunk of nuclear waste from a nuke plant is. I think I still have a plastic cube filled with fly ash (a little desktop paperweight type of thing) somewhere around here from back when I worked in a power plant. There’s no health issue with leaving it sitting on a desk as a conversation piece. Even if it’s not in a sealed container, ash in small amounts isn’t too bad. The problem is that all of those heavy metals and such make their way through the soil and end up in water supplies, so it is very easy to end up with contaminated groundwater in an area near a coal fired plant. You also wouldn’t want to breathe much of it in as dust. It’s definitely more than a bit unhealthy for your lungs.
This is why the EPA, with good reason, has clamped down on coal fired plants for ash pollution.
The plant I worked in sold all of its fly ash. Most of it was purchased by a company that turned it into bricks and concrete. Some of it was also used in fertilizer. The dump trucks that hauled the ash away had covers that would be placed over the bed of the truck to make sure that no ash spilled out during transport.
I’m glad that some use can be made of the ash. But now I wonder how much danger there may be of higher levels of radioactivity in those products. If I lived in a cinder block house made from old fly ash, would it be significantly more unhealthy? I doubt that the heavy metals would be an issue if all the block was covered with siding outside and insulation and drywall on the inside. Or am I wrong in that?
How bad is Ash? Good, bad, he’s the guy with the gun.
A lot of other materials in concrete block and drywall are radioactive as well. I think that once you get the fly ash mixed in with the other stuff in concrete the concentration of radioactive elements usually isn’t high enough to be worth worrying about. It’s no worse than other things that are typically in your house.
Radioactivity is more of a danger when fly ash is loose. Then it’s a fine dust that can easily get into your lungs and cause problems.
As for the other heavy metals and such, once the fly ash is fixed into concrete, these metals are stable and don’t tend to leach out like they do if fly ash is just left loose to settle in soil. So no real health issue there either.
The EPA did a re-evaluation of fly ash for use in construction materials a while back and found no significant hazard.
S’Mart’s top of the line.
So I’m guessing that there’s not enough heavy metals in most ash to be worth reclaiming.