Rare plants that ‘bleed’ nickel | Hacker News Reader

Rare plants that ‘bleed’ nickel

bbc.com

113 pointspseudolus34 comments

Mushrooms (and mycelium) can perform similar operations.

Some fungi can accumulate and translocate heavy metal ions and radioactive isotopes out of a system by drawing them into their mycelia network, where they eventually accumulate in the fruiting body (actual mushroom) and can be removed.

These fungi also produce many metabolites which can increase the solubility of certain metals via reduction, methylation, or dealkylation reactions with the metals.

The mycelial network can also be used as a filter to bind to certain heavy metal ions in contaminated water, where they eventually get chelated, adsorbed and entrapped in the fungal fell wall. The company VTT Technical developed a process and was able to recover 80% of the gold produced through the processing of old cell phones and other electronic waste.

What do you do with the mushrooms afterwards? (In the heavy metal case). Presumably you can't eat them, burn them... Do you just pile them up somewhere?

From watching chemistry videos on YouTube, burning them seems like the way to go. I'm guessing you'd burn them in a purpose-made furnace to melt and concentrate the metals, then put the result into safe storage.

The benefit being that this reduces the energy usage required to fully separate the substances? Otherwise you could just apply this process and cut out the fungus entirely.

By "apply this process", you mean to put the soil or water directly in the furnace? The fungi are performing chemical concentration/separation. Depending on how hot you needed to heat the soil to get meaningful separation, you might end up damaging other properties of the soil by heating it so hot.

With water, it would have to be super contaminated for the majority of the dissolved compounds in the water to be heavy metal compounds, so distilling the water would still leave you with some mixture that you'd probably want to chemically separate. At least you wouldn't be causing any damage to the water by boiling it away, but it would be pretty energy-intensive.

Thanks for explaining, I have very little knowledge of chemistry.

This is a pretty good playlist to learn the basics: https://www.youtube.com/playlist?list=PLKhDkilF5o69PqPy-oMCC...

Cool channel in general.

This is one of the core parts of world building of Miyazaki's 1980s Nausicaa manga. A world mostly covered by a vast fungus that is accumulating all the 'bad' things scattered about by the last civilization and eventually making inert sands. https://ekostoriesdotcom.files.wordpress.com/2013/08/nausica...

Is that also featured in the anime movie?

Yeah it’s central to the plot

Which humans did not understand and wish to destroy as they only saw the forest (which they named the Sea of Corruption) as toxic and threatening the existence of their civilization (both also true).

It's very pointed criticism of our own self-serving approach to environmentalism.

I know it's old now but it's still on my to watch and to read list so you might add a spoiler tag or something.

So can bacteria, in this case gold. https://www.youtube.com/watch?v=wrJkQbKvkNo 1m 17secs long.

Sun Flower plants have been used for decades to remove radiation from soil, and are a very important mitigation element in nuclear disaster cleanup. They grow fast, leech a pretty good amount of radiation from the soil, are incredibly cheap, and require little care.

That's pretty interesting. I remember in the orignal Teenage Mutant Ninja Turtles movie they found sunflowers growing over a toxic spill, but I always thought it was just to show that the spilled chemicals made things grow extra large, but it turns out it was just a lazy attempt at a cleanup.

Strangely enough, many years ago I read the following webcomic about something similar:

http://www.rhjunior.com/tales-of-the-questor-0587/

The story was about a racoon farmer trying to leech bauxite from the soil and created a plant to do it.

Where does the leached radiation go? What happens to the plant matter after the sunflowers die? Their seeds (and are the seeds viable?)?

I am curious.

It needs to be harvested and disposed of (i.e. locked away), but large scale agriculture makes this a solved problem.

I imagine that at least some of the seeds are viable, but pretty much the entire plant (seeds and all) is radioactive and needs to be collected, which for sunflowers means getting to them before they disperse their seeds to the winds.

Several people have talked about plants leaching "radiation out of the soil".

The plants are not separating isotopes. What they actually mean is the plants leach elements than happen to be radioactive. It would be nice if they said what elements.

This is super neat! Off-topic complaint about the text:

"Some nickel-loving species like Alyssum murale, native to Italy, can take up to 30,000 micrograms of nickel per 1g dried leaf."

30,000 micrograms, also known as 30 milligrams?

Does not sound as impressive, I suppose.

It's an unwelcome statistical spin but it's still ~3% by weight so not that bad.

There was a discussion about such plants and phytomining for a post from a few months ago. It got me more interesting in the topic. Here is the post from 6 months ago for the article and discussion: https://news.ycombinator.com/item?id=22457338

Doesnt the use of these plants deplete the metals from the soil? How many seasons can they be grown?

They wouldn't mind having no nickel in the soil, what they do is segregate the nickel into special vacuoles as a protection mechanism against the poisonous metal.

The parent posters point is that it the initial part of the story confusingly paints this as a way to generate "crops" of the metal almost like general farming.

But it's not mentioned for how long those metal bearing crops would potentially grow. If it was only (say) 2 seasons, it doesn't seem worthwhile. Conversely, if it would be (say) 200 years, that's a different story. :)

That's the point. We use crops like mustard for phytoremediation because they do uptake certain undesirable compounds like metals.

These plants, and other plants like this (plants that can suck up metals from their soil/environment) could be very useful for a future Mars colony...

They could be useful for soil remediation here on Earth as well.

How does it work? I figured you'd have to somehow dispose them in a way such that it doesn't reenter the biosphere.

The beauty of it is that even as the metals become concentrated in the plants they're removed from the biosphere, so all you have to do is process the plants, extract the metals the same way you would from an ore, and dispose of the remains. A valuable ore may only contain a few percent of the precious metal with the rest being silicon, carbon, or other base elements.

Yes, it's called 'biomining' and there have been several startups working to engineer organisms to do this. eg Universal Biomining working on copper (with bacteria) and a team at University of Washington who took an enzyme from rat's livers and put it in a plant to remove VOC's from the air (successfully!)!

Yes, rice growing is good for drawing out arsenic from the soil. Actually measuring what tree's have drawn up from the ground has been used by those looking for gold to access an area - https://www.newscientist.com/article/2213033-a-company-has-u...

Look into phytoremediation. It's already being used.

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