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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.
Can you imagine you walk into an arsenic mine that looks like a peach orchard and decide to sample the goods?
It's cool that people are engineering plants and critters to concentrate these potentially toxic compounds...but what happens when the plant or bug dies? You still have the question of collecting the remains and then doing something safe with them.
Also, some plants already concentrate arsenic in their seeds. (It's been a while since I heard this, but I seem to recall it's either apples or apricots.)
Oh yeah. First post!
Oh, go on, check out my job.
It's the choice of an old and tired generation!
Chew on this!
Feeling down? Don't stick around! Genetically Engineered Arsenic Tobacco - Jack Kervorkian Chew!
oh I forgot...
2. ???
3. Profit!
What I would like to know is how they plan to get the base minerals, considering soils have tyically minimal mineralization and the elements tend to be in very low concentrations.
I would think that this would only work for rare earth elements and the like, not so good for base metals.
Still, after seeing what mining does to the landscape, anything is better.
"I propose we leave math to the machines and go play outside" -- Calvin
. . . or you'll end up like Stan here:
l
http://www.ananova.com/news/story/sm_683401.htm
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!!
Does anyone have any more useful links than this one? I know it's in Nature, so there's probably not a free site that directly links the article, but are there any more brain heavy synopses of this article anywhere?
I am interested in several things:
1) what does the Arsenic turn into (chemically speaking). Does the plant change the chemical bonding? I think that most aresnic is stored as sodium arsenate (I could be wrong) if it changes it to something more managable, it would be much better than if it simply concentrates it. HOWEVER, concentrating it is, by itself, an incredible step forward. Period.
2) is it possible to seed these as "suicide" plants, EG: plants that produce no pollen or seeds?
hmmmm?
The plants are probably just a first step.
Obviously, you harvest the plants and cart them away once they have done their work.
You could burn the plants under controlled conditions and chemically extract the arsenic -- a metal, as I recall -- from the ash.
Even if you didn't burn 'em:
If the plants are really concentrating the stuff, you'll have far less waste to deal with. Say, ten tons of branches and leaves rather than one hundred tons of soil. They might still end up in barrels in dumps, but there will be far fewer barrels.
"...Some scientists even see the day when trees and grasses will be used to mine metals and minerals without disturbing the soil." That demonstrates why some people calling themselves 'scientists' should stick to their fields. Sucking up miniscule amounts of metals with plants would only deplete the 'crustal abundance' of minerals within the narrow range of plant roots, and the average American requires over 45,000 pounds of newly-mined minerals every year. I work in the mineral industry, and I am a scientist. This smells like a grant proposal that got by someone. Suckers!
Quite the reverse, I am quite positive these species have been engineered to clean landfills of heavy metals that are otherwise very difficult to extract. There is no other direct reason to engineer plants other than the mining benefit. The mining benefit is very likely commercially, but definately politically, secondary to cleaning (often suburban) areas of waste.
Of those to whom much is given, much is required.
The topic of this article is highly misleading. One would think plants were capable of mining for metals like iron, copper or various mined good, while the real use is cleaning up the soil from any heavy-metal contamination, such as the arsenic example. A more practical use in the local neighbohrhood for this would be to clean the ground around older gas stations or clean the ground of heavy-metals where there used to be a steel mill.
Hate me!
The first group of researchers added a gene from the E. coli bacteria and one from soybeans to make Arabidopsis thaliana, a distant relative of cabbage, develop its taste for arsenic.... The plant efficiently pumps arsenic from the soil and stores it in its leaves, where it can be easily harvested and disposed of.
Oh, sure, as if cabbage didn't taste bad enough already....
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
A large amount of our water problems have to do with burning fossil fuels with heavy metals. Why? Plants have always been pretty at good at absorbing nasty stuff like arsenic, mercury, etc. We burn the coal/oil/whatever, and that stuff goes into the atmosphere, gets absorbed by clouds, and then gets into the water cycle. Then we find this stuff in the our water and fish.
It gets in the fish because algae and water lilys also absorb the metals pretty well. Then fish eat the algae...Note that if you live in the Northeast US (like I used to), you can't eat freshwater fish anymore. All the lakes (with a few exceptions) are polluted with mercury, even the ones far far away from industrial factories.
So modifying plants to absorb more heavy metals is just going to cause problems for 1) future generations (granted it takes a helluva long time for plants to die and make coal, but still...), and 2) current people who hunt for food (like when Mr. Deer comes over and nibbles on that arsenic-laden blueberry bush).
Since when is taking toxic material out of the ground and letting it sit on the surface (where rain washes it into rivers, animals eat it...people eat it) a good idea? Maybe it will keep it out of aquafers in the short term, but it is still going to cause more problems than it's worth.
The Right Reverend K. Reid Wightman,
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...