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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.
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
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.
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...