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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 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!
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The plant efficiently pumps arsenic from the soil and stores it in its leaves, where it can be easily harvested and disposed of.
Presumably, said plant is efficiently pumping arsenic from a Superfund site containing large amounts of..."disposed" arsenic!
Do I detect circular logic here?
WHERE THE HELL DO YOU DUMP THE PLANTS? (Another Superfund site?)
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
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.
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!
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,
and all the other woodland creatures. Also, can't forget about the insects that naturally feed on these plants.
It's easy to keep humans from eating these plants; however, there are always the ones that don't read the warning signs and jump the barbed wire fence we'll read about in the Darwin awards.
But what will happen to the animals, insects, fungi, bacteria, etc that will feed on these plants?
And what happens when the leaves fall off the trees? When they decay won't they contaminate the soil
If I drive fast enough at the red light, it'll appear green.