Field of Science

Plant "eats" heavy metal

First, TPP hates any science "news" article that says plants "eat" anything. What a stupid thing to say. Plants don't "eat" carbon dioxide either although they do absorb it. That being said, here's an otherwise interesting article about heavy metal accumulation in a plant. Heavy metal accumulation in plants is nothing new; they all basically do it because for some reason plants can't get rid of a heavy metal (plants don't "crap" either) once they absorb it. Now heavy metals are toxic, and plants can absorb them in non-toxic amounts, transport them across membranes and cytoplasm, and then accumulate them inside vacuoles, a handy compartment where it can accumulate in toxic amounts.  This is part of a phenomenon called biological magnification, and this is why heavy metal pollution and the recycling of sewage sludge can be a problem.  At any rate some plants are hyper-accumulators and they can take up and accumulate a whole bundle bunch of heavy metal to the point where the plant is quite toxic although unaffected itself.  In the western USA some plants accumulate selenium from certain types of soils, and cattle grazing on these heavy metal accumulators develop an intoxication called "blind staggers". The plant in this story accumulates nickel to such a level that it makes up about 2% of the biomass of the plant (the amount of stuff left after removing water).  Wow, talk about a wooden nickel!  To put that in scientific terms, it's a lot. The idea has been around for some time that such plants might allow you to bio-mine certain elements that are too diffuse to be obtained through physical methods, or perhaps to remove dangerous heavy metals from a polluted area so they can be put where exactly?  TPP has always been unclear on this last point. This is why heavy metal pollution is a bad thing. 

1 comment:

Curious Chemeng said...

It could either be stored (at a much lower volume than the contaminated soil) or the metal could be extracted and sent on for further refining. You certainly wouldn't want to just leave them there.