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Earth Science

Some Clever Farmers are Harvesting Metals From Plants (nytimes.com) 94

The New York Times reports: Some of Earth's plants have fallen in love with metal. With roots that act practically like magnets, these organisms -- about 700 are known -- flourish in metal-rich soils that make hundreds of thousands of other plant species flee or die....

The plants not only collect the soil's minerals into their bodies but seem to hoard them to "ridiculous" levels, said Alan Baker, a visiting botany professor at the University of Melbourne who has researched the relationship between plants and their soils since the 1970s. This vegetation could be the world's most efficient, solar-powered mineral smelters. What if, as a partial substitute to traditional, energy-intensive and environmentally costly mining and smelting, the world harvested nickel plants...?

On a plot of land rented from a rural village on the Malaysian side of the island of Borneo, Dr. Baker and an international team of colleagues have proved it at small scale. Every six to 12 months, a farmer shaves off one foot of growth from these nickel-hyper-accumulating plants and either burns or squeezes the metal out. After a short purification, farmers could hold in their hands roughly 500 pounds of nickel citrate, potentially worth thousands of dollars on international markets. Now, as the team scales up to the world's largest trial at nearly 50 acres, their target audience is industry. In a decade, the researchers hope that a sizable portion of insatiable consumer demand for base metals and rare minerals could be filled by the same kind of farming that produces the world's coconuts and coffee... [T]he technology has the additional value of enabling areas with toxic soils to be made productive...

Now, after decades behind the lock and key of patents, Dr. Baker said, "the brakes are off the system."

Long-time Slashdot reader necro81 adds "This process, called phytomining, cannot supplant the scale of traditional mining, but could make a dent in the world's demand for nickel, cobalt, and zinc.

"Small-holding farmers could earn more from phytomining than from coaxing food crops from metal-laden soils. Using these plants could also help clean brownfields left over from prior industrial use."
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Some Clever Farmers are Harvesting Metals From Plants

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  • Comment removed based on user account deletion
    • by caseih ( 160668 ) on Saturday February 29, 2020 @03:05PM (#59782446)

      I farm for a living and I am also excited about research being done into finding microbes that work with traditional non fixing crops. Staples like wheat. And you're right. Working with nature to be productive is the way forward. Nearly every farmer I talk to today wants to do things to build soil health. I don't love synthetic fertilizers. I worry a lot about fungicides and insecticides, especially fungicides effect on soil microbes. Healthier soils mean there are less weeds, less disease, and so less pesticides required. In some ways it's a time if great fear with climate change, but it's also a time of exciting (re) Discovery. Quite a few guys are experimenting with be intercropping to get more diversity and a more natural way of growing There is a roll to play in this by the big ag companies. They aren't just trying to wreck the planet for money's sake. They recognize that if we fail as farmers they lose their business.

      Anyway using plants to concentrate otherwise toxic metals is awesome! I don't think this will be used to displace food production. But maybe in rotation with food production to improve soil health and promote more diversity. Certainly to clean up damaged ecosystems.

      • Healthier soils mean there are less weeds

        Why would healthier soils have fewer weeds?

        • by Anonymous Coward on Saturday February 29, 2020 @03:43PM (#59782542)

          Weeds are typically "pioneer species." They proliferate where soil conditions are too poor to support more normal crops. Solve the soil problems and weeds no longer hold a survival advantage over the other crops. Thus, "fewer" weeds with respect to the plants you wanted to grow.

          • That makes sense, I was wondering about that. It makes sense that if you're growing tomatoes and the soil is perfect for tomatoes, it will be less perfect for anything else, and thus the tomatoes will out-compete whatever you consider weeds in that context.

            • Conditions where the soil is perfect for one crop are rare, and typically only found in highly artificial situations (e.g. in a pot with 'made' soil or compost). The weeds that proliferate where soils are poor are not typically the most important, unless they also succeed when the soils are good. The important weeds tend to be those that require the same conditions, and therefore proliferate where the crop succeeds. Even a small change in the weather can then lead to the weed outperforming the crop. Fewer w
              • Also depends on your definition of "weed". I read somewhere that Douglas Fir is a major "weed" in New Zealand. So what is an important crop somewhere can be an invasive weed elsewhere, given the right conditions and lack of native competition.
    • Big Ag is not sustainable, and is being replaced.

      Which has the obvious corollary that we'll need to trim the human population by a billion or several (which is something we've known since the 1970s). My personal estimate has been (for the last couple of decades) that we need to decrease by 2 to 4 Gdeath.

      Coronavirus is probably not in that league.

  • Comment removed based on user account deletion
    • by LynnwoodRooster ( 966895 ) on Saturday February 29, 2020 @03:14PM (#59782460) Journal
      Metal content of US coins [azom.com] - about 1.25 grams of Nickel in a nickel. At today's price (around $12,277 per ton), that's about $0.013 worth of Nickel in the nickel. It's going to cost more to refine and separate the nickel from the copper it's mixed with, than the value of Nickel you'd get out of the process.
    • So, what's the cost to produce a nickel from nickel? If it's over five cents. Then just melt coin.

      Note: it's illegal for *Americans* to deface US currency.

      Only if you put the defaced money back into circulation. The law was originally about shaving precious metal from coins.

      • by EvilSS ( 557649 ) on Saturday February 29, 2020 @03:32PM (#59782514)
        Yep, however it's also illegal to melt down US one-cent and five-cent coins for their metal content, or to sell or export those coins for that purpose. This is covered by the Code of Federal Regulations (CFR) Title 31, Subtitle B, Chapter 1, Part 82, Section 82.1 .

        You are allowed to do it for "educational, amusement, novelty, jewelry, and similar purposes as long as the volumes treated and the nature of the treatment makes it clear that such treatment is not intended as a means by which to profit solely from the value of the metal content of the coins. " Code of Federal Regulations (CFR) Title 31, Subtitle B, Chapter 1, Part 82, Section 82.2
        • Huh. Thanks for the citation. More than once I've idly wondered about the legality of tourist/novelty penny-rolling machines. Now I know.
    • by ediron2 ( 246908 )

      Be warned: nickels are mostly copper. Standard us nickel composition is 75% copper, 25% nickel. Quite an odd amalgam: it cancels the color of copper in the coin.

  • by mykepredko ( 40154 ) on Saturday February 29, 2020 @03:01PM (#59782438) Homepage

    From TFA:

    fter a short purification, farmers could hold in their hands roughly 500 pounds of nickel citrate, potentially worth thousands of dollars on international markets.

    Along with environmental concerns of these plants taking over, it seems that it also makes farmers rich and gives them the strength of the Hulk.

    • The article isn't clear on numbers, but from an agro-economic perspective, 50 acres of land to make thousands of dollars a year isn't a lot of money. Plenty of "normal" crops will yield more than that.
      • Or, put a solar farm on top of the contaminated soil and you'd get much more than that.
        • That is, if you want to put a solar farm there and have the capital to invest in it. Growing crops has a much lower investment.

          • The obvious option is to lease the land to someone who'd do it. Even a fraction of the income from sold solar power will still be more than a few thousand dollars per year from those fifty acres. Judging from average NREL figures (average total land use of around four acres per GWh per year in the US), a fifty acre solar plant should be able to annually generate electricity worth hundreds of thousands of dollars per year on this area.
      • 50 acres of land to make thousands of dollars a year isn't a lot of money.

        50 acres of land generating a few thousand dollars by extracting metals from the soil, or 50 acres of land generating zero dollars because of metals in the soil.

        Tough choice.

      • You mixed that up. 50 acres is the next plan trial phase. There was nowhere in that that they said the 50 acres was what produced the 500 pounds of nickel citrate.

        • Nah, it doesn't say anywhere how many acres it takes to produce 500 pounds. It doesn't even say they produced 500 pounds.
  • This differs from previous research where heavy metal was derived from plants.
  • by Ol Olsoc ( 1175323 ) on Saturday February 29, 2020 @03:09PM (#59782450)
    FTS: "After a short purification, farmers could hold in their hands roughly 500 pounds of nickel citrate, potentially worth thousands of dollars on international markets."

    Them do be some mighty strong farmers!

  • This tech couldn't hit the market until the patents expired.

  • by dtmos ( 447842 ) * on Saturday February 29, 2020 @03:47PM (#59782546)

    In his 1976 book Imperial Earth, Arthur C. Clarke wrote about a "Golden Reef", in which the corals had been genetically modified to filter gold from sea water.

  • Slash and burn for nickel!
  • Plant alongside roads. Some sort of grass would be ideal. Mow periodically and refine.

    I lost my link, but there is a video made by a guy who swept a few hundred yards of freeway shoulder, smelted it and got a few beads of platinum. IIRC, the yield of platinum from sweepings exceeded that of some mines.

  • So contrary to what my Dad said, money *does* grow on trees...

    "What if, as a partial substitute to traditional, energy-intensive and environmentally costly mining and smelting, the world harvested nickel plants."

  • Would the plants eventually use up the metals?
    • Oh, man, bummer. Now we have to invent plants that don't eat metal to grow there.

    • Yes, and then that land would be better-suited to other crops as a result of the lower metal content. So this is good for farmers who are current trying to eke out crops in marginal land due to metal contamination. Switch to metal then they can grow other crops again later.

  • I wonder if a plant could be selected to absorb radionuclide contamination from places like Fukushima and Chernobyl? Say for example a plant that has an affinity for strontium-90 which, IIRC, decays to either cadmium or nickel.

    • I wonder if a plant could be selected to absorb radionuclide contamination from places like Fukushima and Chernobyl? Say for example a plant that has an affinity for strontium-90 which, IIRC, decays to either cadmium or nickel.

      No. You could, however, remove ALL strontium. The extra neutron isn't going to be noticeable to the plant that concentrates strontium....

      • by ceoyoyo ( 59147 )

        Theoretically you might be able to make an organism that concentrates strontium-90. There's evidence of biological isotopic fractionation (this one is U235: https://www.nature.com/article... [nature.com])

        Don't know why you'd want to for strontium. Just pull it all out. Separating U235 and 238 has more practical applications.

        • by MrKaos ( 858439 )

          Don't know why you'd want to for strontium. Just pull it all out.

          To handle the waste water at Fukushima.

          There's evidence of biological isotopic fractionation (this one is U235: https://www.nature.com/article [nature.com]... [nature.com])

          Thank you very much for that link, that's great news I hope it can be developed into an industrial useful way to extract those radionuclides from the environment. I don't know if the same organism could pull out sr90 and U235 at the same time, however cleaning up mine tailing with algae would be big step forward. Maybe one day it could handle plutonium.

          Separating U235 and 238 has more practical applications.

          Indeed, a biological enrichment process that would effectively be solar powered - what an irony that would be.

          • by ceoyoyo ( 59147 )

            To handle the waste water at Fukushima.

            Why would you want to pull a *particular isotope* of strontium out of the water? There's no reason to leave stable strontium in the water (not that there would be much to start with) so just take it all out. That process will be much more efficient and easier to engineer than trying to fiddle with preferentially extracting specific isotopes.

            • by MrKaos ( 858439 )

              To handle the waste water at Fukushima.

              Why would you want to pull a *particular isotope* of strontium out of the water? There's no reason to leave stable strontium in the water (not that there would be much to start with) so just take it all out. That process will be much more efficient and easier to engineer than trying to fiddle with preferentially extracting specific isotopes.

              sr90 was the motivation however taking it all out would be just as good - thanks!

          • They're asking about the difference between targeting Strontium in general, vs Strontium-90 *specifically*. A strontium collecting plant is sufficient, it doesn't need to be specific about the type of strontium.

            • by MrKaos ( 858439 )

              They're asking about the difference between targeting Strontium in general, vs Strontium-90 *specifically*. A strontium collecting plant is sufficient, it doesn't need to be specific about the type of strontium.

              Thanks for clearing that up, I was focused on the goal as I'm interested in things that could be used to clean up nuclear accidents. However a technique that could be engineered to different types of effluent heavy metals at different industrial sites would be a massive win for dealing with post-industrial activity and accidents.

    • by hey! ( 33014 )

      In principle, sure, but the specific chemistry matters. Strontium mimics calcium, which sits just above it in column 2 of the Periodic Table. So deplete the strontium in the soil this way you're going to have to deplete the calcium too. I think you'd run out of other trace elements the plant needs long before you do that.

      • That's a point, and a good one, since it plays into why Strontium-90 is seen as bad in the first place. It gets uptaken in place of calcium, so you end up with radioactive stuff in your bones/teeth. But for cleaning up strontium contaminated land, a calcium-absorbing plant might be the choice. It may also picking up strontium, so you can clean that up, then you're only dealing with calcium-deficient soil, which is a much more minor problem.

    • by imidan ( 559239 )
      I can't find an article on it at the moment, but I have read about researchers planting grasses that bioaccumulate certain heavy metals, including radioactive isotopes. They've been testing the process at sites with buried (usually low-level) nuclear waste from the cold war. They plant a field of grass and harvest it with a combine equipped with radiation sensors and GPS. By measuring the location and radioactivity of the harvested grass as it's passing through the machine, they can make better maps of the
    • by spth ( 5126797 )

      Brazil nut trees do.

      They accumulate Radium in the nutshells; the Radium content is about a thousand times that of typical plant parts.

  • by ChatHuant ( 801522 ) on Saturday February 29, 2020 @06:50PM (#59782910)

    I'm not at all knowledgeable about farming, so if somebody is better informed, please enlighten me

    If I understand correctly, plants would only be able to extract and concentrate metal they can reach with their roots - so say a couple of meters down from the surface. At the typical concentrations, that won't be a lot - and, unless there is some mechanism that renews the metal in the superficial layers, it would be exhausted in a few years. I can see bio-concentration work in the sea, where the water is continuously renewed. But I don't know any processes that will refresh the metal contents of the ground.

    • Re:Question (Score:4, Interesting)

      by ediron2 ( 246908 ) on Sunday March 01, 2020 @01:30AM (#59783538) Journal

      You're right. But if assay shows the soil is high in X recoverable mineral, 'mine' it out and then rotate in new dirt into the soil. The key point is that smelting and other recovery mechanisms are energy intensive and often have a threshold below which they're not economically viable, but if a plant accumulates X, that is a different economic equation.

      Last of all, imagine using this concept & finding plants that recover rare earths from landfills, reduce harmful metals in contaminated topsoil, etc.

    • That happens with regular mining, too. It eventually runs out.

    • That's not really the point. It's not a completely renewable source. This just allows contaminated land to have productive value, and the end result is it's cleaned up for other purposes.

      But also, all that stuff we use goes somewhere, back into the ground at some point. So you could something like this on landfill sites perhaps, too. Elements aren't actually *consumed* after all, unless it's in a reactor.

    • At least some of the plants in use for this (I too, didn't RTFA, because it's paywalled and I don't want to pay unnecessary money to American companies ; instead I went to read some of the technical literature on the subject, stretching back over the last several decades. I posted the links while this was still a submission, but not on the front page, but the editor has declined to edit them in), are "top harvested" where you cut the top metre or two of the plant off, which then re-grows. The plant's bioche
  • If they don't codename this project Tiberium they should be deported.
  • If you chew enough of these plants, you could acquire nickel fillings for your cavities!
    This would save on dental costs!

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