I think polyparadigm might be right, if you have trees they may have absorbed pollutants though it seems some plants absorb heavy metals and some don't, the explaintation for why plants absorb heavy metals is to protect themselves from animals, who don't eat them if they get poisoned by all the metals that the plants have absorbed.
If this is a chance to talk about bio-remediation, well, here is what i have gleaned about it though as i started writting here at the same time, about, as i got interested in finding out about bioremediation my studies came to an abrupt halt.
There is
phitoremediation plants used to clean up soil,
mycoremediation fung¡ used to clean up soil
bioremediation bacteria used to clean up soil.
May be there are more things like algaeremediation but i have not got there yet.
These words are handy if you are navigating on the internet to study these questions. though simpler words like, "bacteria clean soil" can bring the same result, and if that does not work you have to think up some other simple phrase that will get you there.
There is also
phitomining and probably
micomining recovering metal plants have absorbed from soils and profiting from the clean up.
These natural cleaners work in several different ways. The brief discussion of these without examples are written here in this essay in heavy type letters so that those who anly want the basics can just read the heavy type.
1. There are plants and fungi that absorb whatever it is you want to clean up and then you harvest them and put the crop somewhere safe or mine it to recover the pollutant and use the pollutant again. As, listening to horses, Jennifer Hall, suggests, when she cries out for the selenium to be taken from places where there is too much selenium, to places where there is a lack of selenium. This simple collection of pollutants using living organisms to collect them is functional largely when the pollutant is a atom, like lead, mercury etc. I imagine. I have just been reading about tamarix trees in Jesus Charcos book "Guia
de los Árboles y Árbustos del Norte de Africa", and some varieties of "tamarix" bare salty soils well. They have salt sweating glands on their branches and trunks. There is one plant you could use to absorb salt. You could harvest it and wash the salt that is deposited on its branches by salt the sweating glands of the plants and then dispose of the salt in a way that did not hurt the land.
Jesus Charco says that
the tamarix amplexicaulis can be so covered in the salt it has sweated that the only branches that aren't completely covered with salt are the main ones and trunks. Apart from the amplexicaulis Jesus Charco says the
africana, boveana, canariensis, y parviflora, in diferent grades have salt sweating glands. Only the aphylla, that he says is so good for holding dunes, cannot handle salt.
2. Then there is the destruction of poisonous molecules, the break down of pretty unbiodegradable molecules like DDT. Paul Stamets says fungi can break down the molecular structure of these substances and, molecular structure changed, polluntant destroyed. This is to say that with the right mushroom, bacteria, plants, digesting them they become biodegradable. The simplest example is oyster mushrooms who eat things like
wood, full of carbohydrates so they are used to breaking down carbohydrate molecules. They realease substances into the soil, in their exodigestion, that dissolve the bonds between
carbon and hydrogen, so why not
feed them on hydro carbides, petrol? Well he did and they gobbled up the hydro carbides, petrol, changing its molecular structure and turning it into themselves, something totally different. Super cool, what. We can use canceriginouse substances on our soils and he can clean them up for us.
He trained some types of fungi to break down VX toxin molecules, the toxin used by Saddam Hussan to kill people with, a pretty unbiodegradable substance.
He can break down pesticides and herbicides if i remember right. That is one of the reasons why he is such a heroe. We can clean up chemical warfare sights so they stop being dangerouse places or get rid of stores of such substances by changing them into something that is not harmfull instead of by leaving poisons shut up somewhere where maybe they might get out and start hurting us again.
A lot of his book, Mycelium Running, is published in internet though not the whole of it enough to learn a lot about different things though in the end you want to, and in my case do, buy his book. If you look up Paul Stamet Mycellium Running and open up from the choice of entries on the internet the one put in by google, you can learn a lot for free and its an easy read.
He also trains fungi to breakdown damaging molecules instead of just finding fungi that will do it. He trains them by choosing fungi that break down similar substances and then introducing the poisons he wants them to undo into their enviroment so they become used to them and then by slowly reducing the other foods availiable for the fungi untill it is, "eat from the constitutant parts of the poison or die of hunger" and they learn to dissolve the bonds between the atoms of the poisonous molecule turning it into a mountain of carbon, hydrogen, potassium for example, atoms, of little power to harm us. He succeeds in training them. You have then to buy his varieties if you want to do bioremediation in some cases.
I suppose this sort of remediation is what is at work in Geoff Lawtons project near the Dead Sea where everything is super salty. He, in this inhospitable place, built loose stonewalls, to catch dew i suppose, he built swales to harvest rain water in such a way as to make the rainwater collected, permeate the soil well and thoroughly. instead of running of the land. He built soft mounds on each side of the swales and put on half a metre of mulch on the soft countour mounds either side of the swales and micro drip system on the contour mounds and planted the mounds with trees and soil started to appear and to fill with life and even fungi and of course bacteria some of which do bioremediation, maybe such a salty place already has a amount of salt in the soil had been reduced.
The authorities thought the salt must have washed down, the salt had not been washed though, they had used very little irrigation, the microdrip they put on the contour mounds.
Geoff Lawton thinks the salt had not disappeared but become inert, been locked up, become insoluble. I suppose he needs the right scientist to tell him which of these things had happened or if something else had happened to the salt. Paul Stamets maybe.
3. The other thing about bioremediation, mico remediation, phitoremediation, i don't know if plants do it too, is bacteria and fungi that repackage dangerouse atoms making them less soluble and so safer, harder for plants to absorb or harder to leach into the drinking water system, look up "Pearls before Sline, about a bacteria that changes nuclear waste, it wraps it up in a heme, the best known hemes are hemoglobin. It seems hemes are complicated molecules that have a bit of metal or, in the case of "Pearls Before Slime", uranium inside them. Bacteria can put your poison into a complicated molecule. You can read articles on this, easy to read ones, if you put the phrase "pearls before slime"in to google, newspaper reports of the scientific papers. I am not a chemist, i have a lot to read to understand this better but this is the basic as far as i can understand it. Get the great Paul Stamets to explain it more. agri
rose macaskie.