When was the last time there was a coal fired burner anywhere? :-)

We'd actually have to test the ash itself to see what's in there, and since we're more interested in toxic metals, Logan wouldn't do for that purpose (although they'd tell us the condition of the ash layer in general which we'd want to know as well).

After all this time, a lot of the problems have most likely leached out and headed for the groundwater. At least they aren't going to bother you any longer.

So do you think it ok to try and reseed over it?

Unknown, of course, but it's worth a shot. The Logan test will point out any problems in the surface soil, and most of the feeder roots do tend to be in the top four inches or so.

I'd very strongly advise against growing anything one might eat on that soil until you've had a lead, chromium, etc. test, of course, and I'd minimize the time that any children or pets spend playing on the lawn, but plants can put up with a heck of a lot in terms of contaminants.

Rebalancing calcium and magnesium levels (if necessary) in the lawn will bind up the lead into more inaccessible compounds, which will help--but acceptable exposure for humans is so minimal that I'd still limit time on the lawn for them unless you're sure.

Thanks Morpheus, it's not in a play area but it's good to avoid it. My dad has a garden out back but it's not very close to where the ashes are. How much horizontal spread would you think to occur from the possible heavy metals?

Highly variable. It depends on the sub-strata of the soil (a clay lens or rock face will tend to limit drainage to only horizontal). Mobility of most heavy metals depends strongly on pH; even slightly acidic means they'll move. Neutral to even sligthly alkaline binds them more tightly.

If he has a garden, I'd very, very strongly advise getting the soil tested for lead at the very least in that area. Just to be sure. This isn't something I've done so I'm not sure how to go about it, but the Logan sheet notes that you can call them for the availability of additional tests.

Thanks Morph, I'll see what the soil analysis says (well I'll see what you say it says haha) and see if anything is off. I'll probably have him dig up one area and backfill with dirt but I think the majority of it is eligible for a replant.

If grass was growing on the area before you started working on it, the area will grow grass after you finish working on it.

Coal ash is just that ash. Material coming out of a furnace that has been subject to very high heat, fusing the compounds into the matrix. The compounds that people worry about are there in insoluble salts, fussed into glasses, or have leached out years ago.

Before someone starts to comment, remember that the compounds Pb, Cr, Co, Ni, etc are naturally occurring. Have you ever heard of a toxicity problem from Jade (Co % Al), or other naturally occurring stones we hold as value. Every gem with any color contains heavy metals that give the gem its color. Some of these stones have relatively high levels of heavy metals.

Every stone you find any where in your yard with any color has heavy metals that create that color.

Hence my comment that it's probably leached out. However, that's not at all certain...every ion in the soil is, technically, at least slightly water soluble in some forms, but they're still there in amounts ranging from modest to copious.

Lead soil binds well, being a cation of various valence states, so it's happy to grab onto the cation exchange sites in the soil. Barring displacement, it'll be entirely happy to hang out there until it does get displaced. Root ion pumps are entirely capable of displacing it, just as they are with pretty much any other cation. In that case, displacement means absorption (the plant emits hydrogen ions to balance the charge).

Mulch mowing will simply return the ions to the soil, now bound into a variety of chemicals that will change or break down over time.

That's actually one method of bioremediation, most notably using sunflowers due to their very deep, very wide root systems. The sunflowers are repeatedly removed from the soil, burned in a highly filtered burner, and the ashes discarded appropriately.

>>Have you ever heard of a toxicity problem from Jade (Co % Al), or other naturally occurring stones we hold as value.

The argument is kind of immaterial in this case as a gemstone isn't a (small, high surface area, much more friable and usually far more open-structured) piece of ash but...

Yes. Galena, asbestos (the naturally occurring mineral), and cinnabar have all taken many, many lives. Galena, when worked, releases toxic dust. Asbestos...well, you know about that. Cinnabar releases mercury when disturbed or heated.

Fluorite is dangerous (or even deadly) if swallowed and leaches easily.

http://gizmodo.com/the-9-deadliest-minerals-weve-ever-mined-1638317799

Here's a fun article that's actually scarily accurate.

In these cases, industrial level usage results in widespread problems. In soils, rocks (and gems if you happen to have any in there) slowly degrade due to environmental exposure, releasing their chemicals into the soil. Most of those are harmless. Some are not. And any ion has a chance of being trapped by the soil.

Of more interest is the fact that most city soils are far higher in lead content than most rural soils...from the lead we used to use in gasoline back in the 1970's (post that, lead levels dropped quite quickly and in 1995, the year before the ban, lead levels were extremely low).

That's still true, with some city soils being marginal to inappropriate for vegetable gardening decades later. The lead's still hanging around forty years after the levels decreased.

Fortunately, it's soil bound, so environmental exposure levels to passers-by is effectively nil. But plants, which exude acids from their roots, can release it and absorb the lead pretty easily.

Coal ash isn't that bad. I work in the fossil fuel industries and while yes it has small amounts of metals in it.. It has been used for ag purposes. Especially fly ash and gypsum.