excess copper in soil- how to fix

Hi, I wanted to start a new garden in an area where a large boat was stored. I had the soil tested for heavy metals and there is 2205 ppm of copper and lead 78ppm, zink181ppm. I was informed the lead and zink are within normal levels and would not be a problem. But the copper is. So what are some ideas to fix this. The copper came from the anti-fouling paint used on the bottom of the boat. The soil is sandy and bare right now. I have done some research but most suggestions are for industrial areas. Would any kind of mushrooms help? The soil testing people suggested two layers of weed barrier and raised beds.

Sounds like what you need is some phytoremediation!

https://www.resilience.org/stories/2014-08-11/using-plants-to-clean-contaminated-soil/

Sounds like a really interesting project actually, since you already have a baseline from the original soil analysis. Reading that article mentioned that mustard greens will accumulate copper - and they grow super fast, so you might be able to get multiple "harvests" per season. The plants could be dried and burned, or maybe if they were spread over a large enough area it would effectively dilute the copper.

I am looking into phytoremediation, The high level of copper may hamper plants from growing as the level is so high. I plan to try a small test patch for a growing season and have the soil tested again to see if there is any difference. Mustard and some grasses may work. Will let you know this project goes. The area is one of the sunnier places in the yard. I am in a  zone 6.

This might be useful: https://en.wikipedia.org/wiki/List_of_hyperaccumulators

Yes, Mushrooms!

Mushrooms are known to have the ability to accumulate heavy metals. These pollutants have detrimental effects not just on organisms in the environment, but also on humans through the food chain.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6221449/

#1  ZEOLITE (cheaper by the ton, around $90.00 US.  Keep in mind, I only looked at the idea of tying the copper to the zeolite and not of removing it. It MAY be the zeolite would hold the copper such that its release would be more akin to needed levels, just like when NASA uses pre-charged zeolite for hydroponic gardening in space.

https://www.911metallurgist.com/zeolites-remove-heavy-metals-water/


There is a TON more information on zeolite. It's, almost, like the most well known, best kept secret out there.  It's everywhere and you may have used it.

NOW, down the wild side, and for some fun. I copper plate. Doing so takes under a volt and under an amp.  Power is applied to the anode, which is a cooper item, to replace copper lost to the plating process.  Here, we don't wan to replace it. Accordingly, we switch the anode to, let's say, graphite or a screen plated in platinum.  The target piece, a piece of iron, copper, graphite coated wood, anything that will conduct and allow the copper to attach.

You could section off an area for experimentation and feed several anode rods into the soil, along with spaced cathodes.  It'd be fun to see what happened when you ran a few volts and an amp there for a few days, then tested the involved soil.

You'd have to keep the soil moist, for conductivity.

For my plating baths, I use distilled water and sulfuric acid with some copper sulfate.  Obviously, distilled water would be immediately tainted, so I'd just go with tap water.  No copper sulfate, of course, because you don't want to put copper back into the soil or and want to rely on what's already there.  As for the sulfuric acid, eh, maybe some vinegar.

Just play, who know, you may have the next, new, patentable process for remediation.




https://www.researchgate.net/publication/270760835_Using_of_zeolite_for_copper_and_zinc_removal_under_acidic_conditions

Bioaccumulation sounds good but where do you put the accumulated copper? And how many decades would it take to get Copper down to an acceptable level? In sandy soils most excessive nutrients can be leached downward, away from shallow roots, given sufficient rain/irrigation. In more normally mineral-balanced soils, if Copper were excessive I would suggest adding loads of Iron, which slows Copper uptake into plants. Around here we run into the opposite scenario, where high Iron and and a high Iron/Manganese ratio, due to sandy soils and excessive tillage call for Copper applications. Ultimately, if you need a crop now, adding 6" of more nutrient-balanced topsoil and planting over the existing stuff might be the best option. Those Lead and Zinc levels are quite excessive too. I don't know how to avoid the Lead toxicity other than using a different garden spot, but excess Zinc is best balanced by adding way more Phosphorus.

I am not an expert on that, although I have a few ideas.

You'd need to answer a few question. What is the surface you need to clean off ? How deep the contamination goes ? What kind of soil is there, clay, sandy, humus ?

Are these metals the only contamination there ? No chemical leaching from the paint, no mineral oil or anything that would come out ? It this an industrial site ?

The bigger the surface, the more scalable the method will need to be. Adding more compost in a flower pot with tainted soil, sure, but if you have one hectare it might be harder. If the contamination has reached deep into the soil, you will probably need to grow phytoremediating plants that have pivoting roots. If there is a water source, it might be leaching into it, something that should be taken into account.

The soil type will determine which plant can be grown there easily. I don't know much about weeds that soak up copper, but they would be a good starting point to look into.

Since you're focusing on healing the soil, it's interesting to know if there are other chemicals presents, like pesticides or particular chemical toxins.

If copper is the only troublesome metal, perhaps you can consider re-using the plants grown there, to extract the copper from them.

I am not an expert on mycology yet, but I know that diluted copper sulfate is used as a fungicide to grow vines, so mushrooms might not be the best solutions. However it's possible  that copper works against vines pathogens, but not against all mushrooms.

Basically, you can use plants to extract it, and compost seem to help bind the copper. Then it would depend on what you grow there: if the food you grow doesn't accumulate copper at all, it might offer another level of protection.

PS: One link that might helps: https://www.permaculturenews.org/2016/11/14/phytoremediation/

I'm not sure where you're located and whether or not this would be a climate suitable option, but there are a number of studies that have been done on vetiver grass for heavy metal bio-accumulation. Most of what I've come across indicates that uptake or binding of the metals is greatly assisted by soil drenches of humic acid. A lot of the studies are lead focused, but copper is consistently mentioned in the mix often enough that it could be worth considering.

Vetiver would definitely be a multi-year solution, so if you're looking for something faster it probably won't be the best choice.

Best of luck in bringing your soil back to health!

Thanks for all the good info. The site is sandy coastal soil. Drains well, I am in a zone 6. I am going to try mustard and maybe sunflowers  this year and see what difference it makes. I will dry the plants then burn and spread the ashes around the wild area of the yard. I don't any experience growing mushrooms and the area doesn't seem like mushrooms would like it- too dry and sandy. I only had a heavy metals test done- I knew the anti-fouling paint used on the boat would be a problem. As for other chemicals, this area was not used for anything else.  I will look into  vetiver grass , see if it will grow here.  

Be careful when burning the plants, as the copper will simply end up in the ashes (possibly a bit of it in the smoke too !). So if you spray those ashes again on the soil you decontaminated, I think you're just recontaminating it...

However, "diluting" that copper could be an option. Ideally, you'd find a place which has a copper deficit (not sure if it's essential to plants, but it important in human to have bits of it), so that you end up fixing another place.

I heard about phytomining, using plants to get minerals, obviously don't expect to start getting copper by the ton, but perhaps you could find a way to extract the copper from the ashes. "how did you get that copper cup ? - oh, I grew it" is a scenario I'd definitely want to be a part of.

Hi. To update my try on the copper in soil fix. I put a thin layer of compost down and then planted in two separate spots- a mustard mix and a clover mix. Both came up and grew slowly to about 1/2 -1 inch tall, then stopped growing. The mustard died away and now there is only a couple of clover plants left. So I am glad I made the raised beds. The plants in the beds are doing very well. I will keep trying to grow something in the ground- to cover the bare dirt, but won't grow any food plants there.

Thanks for the update.
I know you didn't manage to grow the plants in the contaminated soil, but if you did I wouldn't have bothered burning them. It seems to me that as well as potential problems with smoke and dust you would be losing the opportunity to add the biomass you created to the wilder areas. Just putting on (contaminated ashes) isn't that useful to the soil there, but bulky organic matter is more useful I would have thought. Maybe there's something I'm missing.