Return to the Soil Forum | Post a Follow-Up

 o
Black Sand?

Posted by kruise WA (My Page) on
Wed, Apr 24, 13 at 10:46

When I had my hardscape done the landscaper brought in what looks and feels like sand but it's black in color and holds moisture in the areas not directly in the sun. Any idea what it might be made up of? The landscaper has retired and I've been unable to contact him. I want to raise the bed up in another area so I'm looking to add more of that material.


Follow-Up Postings:

 o
RE: Black Sand?

  • Posted by nil13 z21 Mt. Washington L (My Page) on
    Wed, Apr 24, 13 at 11:29

Take a magnet and see if the sand is attracted to it. If so, it is iron slag that is used for sand blasting. It is sometimes called Black Beauty. I would be a little concerned about heavy metal contamination from it though I don't have any info about that happening.


 o
RE: Black Sand?

  • Posted by nil13 z21 Mt. Washington L (My Page) on
    Wed, Apr 24, 13 at 11:36

my mistake, black beauty (the name brand stuff) is coal slag not iron slag. Though I have seen black 'sand' that was iron slag and copper slag as well. One time I got some for an aquarium. ugh big mistake since you clean the glass with a magnet. Well super sharp iron slag, magnets, and a big glass box don't make a very good combination.


 o
RE: Black Sand?

  • Posted by TXEB 9a (My Page) on
    Wed, Apr 24, 13 at 11:53

Likely placer deposit (aka black sand). I believe WA is known for having a fair number of these. Placer deposit black sand is often partially magnetic.


 o
RE: Black Sand?

I suppose if it's magnetic it's due to magnetite (or hematite? not sure if that's magnetic). Magnetite is just an iron mineral that happens to be magnetic.

This is a much more likely scenario than a landscaper using toxic used blasting medium. Not that it couldn't happen. OTOH, when I Googled "Black Sand Washington" the first hit was a page about a project to remove and replace a black sand beach that was made up of granulated slag with high levels of metals.

Here is a link that might be useful: Black Sand Beach


 o
RE: Black Sand?

  • Posted by TXEB 9a (My Page) on
    Wed, Apr 24, 13 at 12:52

tox,

Wouldn't that stuff go to a hazardous waste landfill?


 o
RE: Black Sand?

  • Posted by nil13 z21 Mt. Washington L (My Page) on
    Wed, Apr 24, 13 at 17:05

It'a not used blasting sand. They get clean stuff. But I've seen it at rock yards all over the place being sold as black sand at an unreasonably attractive price. one of the reasons they use slag for sand blasting is because sand is in a way more dangerous because of silicidosis.


 o
RE: Black Sand?

  • Posted by TXEB 9a (My Page) on
    Wed, Apr 24, 13 at 17:10

Like I said, placer deposits - I believe there's a lot of it the NW. It's one of the things the gold prospectors look for.


 o
RE: Black Sand?

  • Posted by nil13 z21 Mt. Washington L (My Page) on
    Wed, Apr 24, 13 at 17:16

Now, my experience with the stuff is only in the SW. Sand, gravel, etc are very local products and placer deposits might be cheaper and more available in the NW than the slag. I would definitely ask first though. However if you see Black Beauty, that is a brand name for coal slag.


 o
RE: Black Sand?

  • Posted by TXEB 9a (My Page) on
    Wed, Apr 24, 13 at 17:28

In addition to asking, a small strong rare earth magnet (they're cheap!) should move the stuff if its "black sand" from a placer deposit - the stuff is mostly mixed iron oxides and is considered partially magnetic.

If you get lucky maybe you'll find some gold, or platinum in it ;-)


 o
RE: Black Sand?

  • Posted by nil13 z21 Mt. Washington L (My Page) on
    Wed, Apr 24, 13 at 17:46

I also don't think it's too crazy to think that landscapers are putting slag places when you can go into any BBS and buy a bag of mine tailings loaded with heavy metals beng sold as fertilizer (ironite).


 o
RE: Black Sand?

  • Posted by nil13 z21 Mt. Washington L (My Page) on
    Wed, Apr 24, 13 at 17:56

wow tox that beach project was crazy. I did a little more digging to find out how that happened. 90 years of dumping 450 tons of slag a day into the river created that beach. crazy.

Here is a link that might be useful: black sand beach history


 o
RE: Black Sand?

Slag would not necessarily go to a haz waste landfill. Quite the contrary. Just so everyone understands, slag is a general term for the glassy waste from metal smelting. It has all the minerals they don't want. It floats to the top of the smelter and the liquid metal sinks to the bottom. Slag has different compositions depending on the ore and other ingredients that go in.

There are ancient (1800s) laws that have the effect of exempting mining wastes from various env. laws and regs that came along later. For example I was at a lead smelter just last month, which has its own landfill of...black sand slag. It does have total metal content (Pb, Zn, Cu etc.) way over what would be safe in a yard, and they are managing it appropriately, but it's certainly not being treated as a hazardous waste.

Hazardous Waste is a very narrow term. There are no Listed Haz Wastes that are smelter slag, so unless it is Characteristic - i.e. leachable - which it is probably not, being glassy...it cant be a RCRA HW, even if the mining exemptions weren't there. This does NOT mean that it's safe to expose people to, as it may have TOTAL metal content at an unsafe level.

I also know that a lot of coal cinders - at least those used for fill in past decades here in MO - are high in arsenic.

All this stuff, when dug out of a remediation site like that beach, would go to a local sanitary landfill as what they call 'Special Waste'. Its location in the landfill is recorded for posterity.

I would not want any of this stuff in my yard, including Black Beauty, which is marketed as a coal slag blasting medium (where it should be contained and disposed and the user is presumably wearing a mask).

Natural black sand sounds lovely though. :-] Don't have any of that here in MO.


 o
RE: Black Sand?

  • Posted by TXEB 9a (My Page) on
    Wed, Apr 24, 13 at 18:39

tox,

thanks for explaining that - makes sense. I never dealt much with the inorganic solids processing world. Where I've worked in the U.S. pretty much everything fell under RCRA HW, except office waste paper. If it could be burned, it went to our six 9's-plus incinerator which was the preferred method, selected and highly controlled waste water streams went to our HW-water treatment facility. The incinerator was water scrubbed and the water went to the ww facility, then the ash went tour our in-perpetuity HW landfill. Rainfall went into a separate storm sewer that went to HW-waster treatment. The sludge from ww went to the incinerator. Construction debris went to the HW landfill. Round and round it all went. Nothing left the system, save office stuff. The intent was a completely closed system, save air emission (highly permitted and regulated), and outflow form tertiary ww (again, highly permitted and regulated).

Hence, when I read the description of the black sand beach and how it was being handled, it sure seemed like HW to me.


 o
RE: Black Sand?

I wonder if it's as simple as just sand mixed with top soil? There's no organic material that I can see.


 o
RE: Black Sand?

Ordinary sand mixed with a dark soil or dark organic matter will, upon close inspection, look like a salt and pepper mix. If it's placer deposit black sand it will look fairly uniformly black, and it will readily settle from water to form a black sandy layer on the bottom of a container (the stuff is very dense, like 2X the density of quartz).


 o
RE: Black Sand?

Around here, many years ago, landscapers used to sell people spent foundry sand as "topsoil" (hey, its black isn't it?). Today we have a company that dredges the organic matter (tree leaves primarily) from the bottom of one of our lakes, mixes that with sand and some lime (they have MSU test it for pH and call it "state tested") and when it is delivered it looks like decent black dirt. After a light rain, however, the organic matter is washed out and you see the light tan sand.
Sandy soils, because of the very large particles, drain quite well, almost too well, but do not hold nutrients at all and so sand needs lots of organic matter so both moisture and nutrients can be held in the plants root zone. Sand varies in color from light tan (almost white) to black depending on the source. Sand is the largest of the soil particles.


 o
RE: Black Sand?

kruise - a simple test for you. Take a "clean" sample of the stuff (don't dig down and get a bunch of dirt). Put it an test tube, bottle, jar or glass, about 1/10th to 1/5th the depth. Add clean water to near the top, then shake or stir to suspend all the stuff in the water, The set it down to rest undisturbed and watch. Sand particles are denser and will settle quickly, and the color will be self evident - silica sand will be pale, placer "black sand" will be black and will settle very quickly.


 o
RE: Black Sand?

From the simple soil tests I frequently post.
1) Soil test for organic matter. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. For example, a good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.


 o
RE: Black Sand?

TX, you must have worked at a really serious industrial facility! I'd be curious to know at least the type of industry (if you don't want to name the employer).

I would say the vast majority of waste with chemical contaminants in the US is not HW in the strict RCRA sense. Overseeing the cleanup of contaminated sites, I'd say well over 90% of what gets treated or hauled away ends up in the local sanitary landfill as Special Waste.


 o
RE: Black Sand?

  • Posted by TXEB 9a (My Page) on
    Fri, Apr 26, 13 at 13:26

tox - like stated over on the sludge thread*, chemical industry, one of the big guys. I don't doubt that most of the stuff hauled off somehow escapes RCRA. In the industry, however, once you are significantly on the RCRA side of things it is probably just easier to live life that way. But to do so, you must have the facilities. The other part had to do with our own ethics and sense of responsibility - we believed in cleaning up after ourselves and not creating problems for others. The biggest issue(s) are typically ancient history, before anyone knew any better.

Then of course there was SARA, CERCLA, TSCA, etc., etc. It always seemed to us that the goal of regulatory agencies was to keep chemicals out of the hands of chemists. :-/

*very nice, and accurate reply to the dialogue on who can throw what into a POTW stream. Two things many forget - the initial generic restrictions without regard to HW classifications (there are a number of them back up at the start of 40 CFR 403, even before you get to HW, and many provide all that is needed to restrict), and state/local POTW ability to restrict.

oops - looks like I departed from gardening topics.
"never mind".


 o
RE: Black Sand?

One of the lessons learned from Love Canal and the toxic waste sites we have around here is that chemicals dumped into the ground often combine there and even of they are inert when dumped they combine wit others and create new and very toxic substances. It has taken around 45 years to get enough of these toxins out of the lakes around here so they are in the process of being removed from the EPAs list of hot spots.
We have far too many people that are unaware of history so we are going to repeat the errors of the 1960s and create more hazardous waste sites that will need Superfund cleanup again.


 o
RE: Black Sand?

>>The biggest issue(s) are typically ancient history, before anyone knew any better.

And that, in fact, is what I do for a living. Some of my sites have gunk under them that dates back well over a century.


 o
RE: Black Sand?

  • Posted by TXEB 9a (My Page) on
    Mon, Apr 29, 13 at 23:26

tox - as a good friend of mine once said, "waste is a terrible thing to mind". ;-)


 o
RE: Black Sand?

Haha, that's a new one, however surprising that sounds.

Re: creating new contaminated sites, it's certainly happening in many parts of the world. Waste control in the US is a lot better than many places and we don't have the burial of drums and pits full of gunk that we had just a few decades ago. Plenty of job security in places like Asia and Africa and Eastern Europe, though. I've heard some scary stories, and I shudder to think how bad it actually is close up.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Soil Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here