That seems to be 15mg/kg of uranium in the fly ash. Fly ash slurry is a mix of fly ash and water to the tune of about 20:80 - 40:60, so call it ~5mg/kg uranium in fly ash slurry. However, the natural concentration of uranium in normal soil or rock is commonly anywhere up to about 5mg/kg, upwards to 20-30mg/kg in some places. Fly ash slurry will of course contain a lot of other toxic (including carcinogenic) stuff, e.g. heavy metals and certain organic chemicals.
Re-read the article, they were testing samples from the spill when it occurred and during clean-up, comparing it to samples from recent years. That higher concentration
was the slurry. That was part of an ongoing investigative report from Knoxville News Sentinel, to which the article I cited alludes, the ash slurry from Kingston was far dirtier than TVA and the state environmental agency (TDEC) admits.
What you're missing was whether or not the slurry included bottom ash, and how much.
On Dec. 22, 2008, about 5.4 million cubic yards of coal ash were released at Tennessee Valley Authority's Kingston Fossil Plant.
www.power-eng.com
www.sciencedirect.com
The concentration of uranium (374mg/kg) and radioactivity in coal bottom ash (CBA) from high-germanium containing coals were much higher than that of …
www.sciencedirect.com
A top-to-bottom tour of fossil fuel sludge.
www.nrdc.org
The U.S. Department of Energy's Office of Scientific and Technical Information
www.osti.gov
The EPA makes no legal distinction between disposal of fly and bottom ash, it's disposed together. Let's assume for the sake of argument the Kingston slurry was a 50% mix which has an approximate 1.4g/cc density according to that paper I just found, so we'll go with a revised estimate of 5.88 billion kilograms of ash slurry by that figure. By weight, 2.94 billion kilograms of ash. The question is, what percentage was fly ash to bottom ash; if it had a mixture in proportion of fly ash to bottom ash by production...
About 90% of that would have been fly ash, or 2.65 billion kilograms -- 39,800 kilograms of uranium from the fly ash component. About 10% of it would have been bottom ash. Most US bituminous coal has the high germanium concentration spoken about in the paper discussing CBA uranium concentrations, so I'm going to use that figure cited as it was the one I could find as a
top end estimate. That paper cites 374mg/Kg of uranium in CBA, so no more than 109,956 kilograms' worth of uranium in the bottom ash. Together, as much as 149,756 kilograms of uranium
might have been spilled, meaning the slurry's uranium concentration
could have feasibly been in the neighborhood of 25.5ppm assuming a 50% water to ash mix.
So, yes, it was
entirely possible for slurry samples of 15ppm to have been found and tested. Which by the way, we haven't even
started talking about coal bottom ash, yet. And again, I want to make it clear I'm discussing
only one radioactive element thus far among
several.
Last, now who's trying to distort the argument? I said this upthread already. Would you care to elaborate on your carefully crafted "commonly anywhere" disclaimer? Actually, I'll do it for you: you're sneaking into the comparison uranium concentration in bedrock and parent layers, notably that of felsic rocks and intrusive formations as well as shales and phosphorites, and soils formed from parent layers of those rocks. The
average of US topsoils is 3ppm, because while most have uranium concentrations well below 1mg/Kg, soils in regions with uranium-rich parent layers have far higher and throw averages out the window. That's what happens when you sneak subsoils and bedrocks with concentrations north of 100ppm into the average.
The closest comparison amid all that is fly ash to granite, except you're continuing to fail to account for one thing: uranium in granite is sequestered. It's not going anywhere unless the rock in which it's sequestered is melted or pulverized, almost all of it is well underground and only released to erosion, and it's not going to result in significant dosage even in the case of unlacquered granite surfaces in the home because uranium and its daughters are alpha and beta emitters that are absorbed by the rock around it. Fly ash
isn't similarly sequestered unless it's converted to cement, and it's not legally required to be thus sequestered. Instead, it's dumped in landfills where it can and does leach into soil and groundwater.
And you have yet to acknowledge I'm pointing out there is a clear double standard in how radioactive waste products are represented, discussed, and handled. Even in the terms and conditions of your own argument as you present it. Why is that?