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Mining Metals Using Plants and Trees?
elroySF writes "An MIT Technology Review article says "...Scientists reported Monday that they have bioengineered a plant capable of absorbing arsenic from soil and sequenced the complete set of genes for a microbe that can remove heavy metals from water." It goes on to say "...Some scientists even see the day when trees and grasses will be used to mine metals and minerals without disturbing the soil."
" We had a story about this a while back.
I read an article in New Scientist several years ago about how the British authorities have planted a number of metal fixing plants in the vicinity of the Firth bridge to absorb the residue from the noxious paint used on the bridge.
This is more along the lines of cleanup or bioremediation, where organic methods of agglutinating very disperse amounts of something dangerous (heavy metals, arsenic, etc. in the soil/aquifer/etc.) into larger, more manageable clumps without disposing of the substrate wholesale. The article mentions things like cleaning up oil spills with bacteria and removing toxic metals from soil. This isn't a technique to remove large, concentrated deposits of metals from the ground, it's actually much the opposite: it removes scattered, relatively small amounts from the environment in a way that facilitates their safe(r) disposal.
It's a cabbage. I don't know about you, but I don't think I'll be walking by a cabbage patch and feel a sudden urge to chow down any time soon. ;-)
Slashdot - News for Herds. Stuff that Splatters.
Yes, you pump arsenic from a disposal site, but the arsenic in that waste will probably be low concentration (just ppm in solids is considered bad).
Imagine that the plant sucks up *all* the arsenic from the soil, and *just* the arsenic. Thousands of tons of crap, which contain a few hundred pounds of arsenic, all of which goes into leaves. You then harvest the plants, put them into compost, shovel out a nice barrel full of arsenic into a secured container for burial, and have your nice thousands of tons of crap cleaned of arsenic. All the arsenic is still there, it's just become a smaller, more manageable problem.
Arsenic is an *element* (although what most people consider arsenic is Arsenolite, As2O3. Arsenic as As metal is pretty rare to find naturally), until you get that whole alchemy thing going and you transmute it into iron, there are no decent forms of arsenic that are completely safe. Everything is about concentration and containment.
MIT did not just think this up. On my desk I have Volume 1, Issue 1 (March, 1999) of the International Journal of Phytoremediation (ISSN15522-6514). The science of phytoremediation is the study on how plants and there associated rhizosphere microbial communities deal with contaminants.
The science of phytoremediation is not new. The US military has studied it for years as a method to clean up metal contaminated soils at gun ranges. One of the problems of phytoremediation with inorganic contaminants (such as lead or aresnic) is what to do with the plants after the remediation program. They can be just as hard to dispose of as the metal contaminated soil. I believe the lead concentrations in one barley crop was so high that they sold the "harvest" to a smelter!!
This is nothing new. Many companies have been doing this for a very long time.
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Here is a
http://science.slashdot.org/science/02/09/3
Ocen Arks International:
http://www.oceanarks.org/LM/Frame
a decent Wired.com article:
http://www.wired.com/news/technology/1,
also see: http://www.berea.edu/sens/living_machine.htm
The Buckminster Fuller Institute
http://www.bfi.org/Trimtab/fall00/living_machin
This UK company
http://www.ltluk.com/
a Battelle Enviro Update article
http://www.battelle.org/Environment/publ
An article from HUD
http://www.hud.gov/local/boi/ie100601.html
The notice from the 1993 confrence on living machines:
http://www.ibiblio.org/london/agriculture/biore
Some info from LSU
http://www.biology.lsu.edu/webfac/cramcharan
Rockbourne Enviro
http://www.rockbourne.net/WastewaterTreat
Korte Organica
http://www.korte.hu/technologies/living_machine
This Time.com article
http://www.time.com/time/reports/environ
One method of removing heavy metals from a heavily polluted area(old factory site, for example) is to plant the entire grounds with trees. Soft pines are often used, for example. As the trees grow and absorb minerals through their roots, they take up almost all of the polluting metals over time and store them in their needles and bark.
There are companies that can be hired to plant and maintain small "cleaning forests" over a period of ten to twenty years, to make sure no one else is harvesting the lumber, and to treat or remove trees that become ill. It's actually very useful, a cheap, efficient(compared to digging up the soil and chemically treating it), and very clean method of getting dangerous substances out of the ground.
Cyanide facts:
There are 0.6 mg/g hydrogen cyanide (HCN) in dried apple seeds. Cite
Natural cyanide is called Amygdalin, chemically it is bonded to a glucose and readily converts to hydrogen cyanide in the body. Herbal places sell it as a miracle cure for cancer. "Amygdalin Tablets & Ampoules www.cytopharma.com" This was an ad that came up during a google search related to cyanide.
50 to 100 mg of cyanide is a lethal dose. Cite
This is about a half-cup to a full cup (80-160grams) of dried apple seeds.
An interesting site on cyanide.
Related:
Smoking of cigarettes commonly releases cyanide. Tobacco smokers have a mean blood cyanide level of 0.4 mcg/cc, which is 2.5 times greater than the level in nonsmokers. Cite
I've had enough abrasive sigs. Kittens are cute and fuzzy.
There's a short article on the findings and also some mention of the concept of phytomining.
The issue with Arsenic metal is that it very easily oxidizes back to As2O3 again.
I'm not disagreeing, I'm just saying that the supply of arsenic mega-outstrips its current demand.
Plants already suck up arsenic from the ground. In fact, garden vegetables which have absorbed toxic levels of heavy metals are a common cause of chronic illness in areas with contaminated soils. The fact that plants do this in the first place make it relatively easy to crank the tendency up a few notches.
Toxic heavy metals already pervade our ecosystem, generally in concentration that make it difficult to remove them. As has already been stated, anything that can take these low concentration (but still dangerous) contaminations and turn them into high concentrations that can be safely removed somewhere is a good thing.
Arsenic can't find its way into the ecosystem in a "macro scale" unless its there in the first place...the soil and the groundwater are very much part of the ecosystem. But in this case, presumable some, in fact large amounts, of the arsenic has been removed when the plants are harvested.
If the test sites are heavily contaminated in the first place, you can bet local ecosystem poisoning has already happened.
As far as "mining" via plants...do you think really think that strip mining would be LESS hard on the environment? Unless the world magically reverts to the stone age, people are going to want metals, and until something better are is introduced, there's little incentive for them to stop doing what works for them already...
If you really think about it, mining is the root of all industries. As I mentioned previously, there would not be computers without mining and more importantly, miners. (People have dehumanized miners by referring to the 'mining industry'). Nor would there be modern agriculture (irrigation, equipment, transportation, fertilizers, etc. etc.), healthcare (instruments, medicines, equipment, transportation, brick, glass, steel, etc.) and...well you get the point. The steel nails in your house, the steel blades to cut the wood, the copper wires to transfer the electricity...ok, ok.
However, if "microorganisms" is substituted for "trees and grasses", then this is not science fiction but inductrial fact. Now it is true that currently this is used for second stage processing on piles that have already been crushed and ground into small pieces rather than for the actual mining process, but it is not such a stretch to imagine introducing the little beasties directly into the ore-body in due course. And way preferable to digging holes and expecting people to work inside them.
You can either gather the plants and burn them to concentrate the heavy metals or compost them and replant in the compost to concentrate the metals even more. The great thing about the plants is that they filter a lot of contaminated water (which essentially ends up as distilled rain) over their lifetime with out burning oil for industrial processing or using industrial chemicals. And it is cheep too.
In developed areas there is a lot of lead contamination around old houses (lead paint) and cities (leaded gasoline), or mercury from florescent lights. Uranium from depleted bullets (which turn into a power aerosol upon impact) has just as strong a organiometallic effect as arsenic.
All of these things can turn you madder than a hatter (this is an old phrase resulting from the use of mercury in the hat making industry at one time. Or as dull as a printer (lead pigment used in news paper ink until the unions forced a change). But it depends on which part of the brain dies first.
These heavy metals have been used in a variety of things that people bring into their homes. In fact a large number of cosmetics are exceedingly poisonous because there are no regulations on what can be in them. Ever wonder what the active ingredient is in those hair dyes for men whose beards are turning white, its lead acetate. Remember, you are what you eat, drink and absorb through your skin. Moonshine isn't the only source of lead poisoning these days!