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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?
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.
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 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....
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.
Riddle me this batman, which of these two cases presents a harder clean-up problem: 100 kg of lead powdered into a fine dust and bound to the soil as various metalic salts, or a 100 kg brick of lead? The problem that is trying to be addressed here is large-scale soil contamination, where the toxic compounds are distributed and diffuse. The original title to this slashdot story (in the grand slashdot tradition) is completely misleading about the goals here, a better title would have been something like "Using plants to concentrate soil contamination for further processing" but that did not have the same tabloid appeal I guess.
At some point someone should to a bit of examination of past slashdot stories and give the rest of us a bit of feedback on which slashdot editors actually read the articles they are linking to and have the brain cells necessary to understand the content of these links. While I dispair for the future any of the slashdot editors have in fields related to science and technology, they can always fall back to a career with the Weekly World News...