Phytoremediation - What could be left on Brown Field Sites?

Question

I am not science based please help. Simple language is best!

Looking at the periodic table what is it possible or not possible to 'extract?' using Phytoremediation on a brown field site.?


What is Phytoremediation?
Phytoremediation consists in depolluting contaminated soils, water or air with plants able to contain, degrade or eliminate metals, pesticides, solvents, explosives, crude oil and its derivatives, and various other contaminants, from the mediums that contain them. It is clean, efficient, inexpensive and non-environmentally disruptive, as opposed to processes that require excavation of soil (Source: Wikapedia).

Answer 1

the technique of phytoremediation has undergone testing in a variety of instances, and has been proven to be effective at helping to depollute certain kinds of substances in brownfields. through degrading root systems and extraction of pollutants through the groundwater, among other ways, the technique is another tool in the battle to reclaim and re-use land that we have abused.

an article by the center for brownfield initiatives in new orleans states that phytoremediation (using plants to 'filter' and de-pollute) can be used in cases where petroleum is the chief pollutant: a common case occurs when an old service station closes, but never removes the underground gas tanks, which eventually leak. the technique is effective in tihs case because most of the pollutants are relatively near the surface (within 6 feet according to the article.)

a research group chose planting bermuda grass as a sound technique for de-polluting brownfields, because the grass forms a high density root system, maximizing contact with the ground. clover has also shown promise, according to the study, in certain cases because its roots simulate microbe growth. trees have also been used to de-pollute, although the time frame required to plant and cultivate trees on a given site makes it less desirable for immediate impact.

tending to the plant life while it 'does its work' can be expensive and time consuming, and so far, phytoremediation is most effective only on lightly to moderately polluted sites. it is not suitable for PCBs.

the chief benefit is that the technique does not require damaging and expensive excavations, and is environmentally and ecologically sound (solar-powered). the site is physically more inviting while the process takes place as an added bonus, although experts would advise against having direct contact with the polluted subsoils for recreational or agricultural purposes.

Answer 2

Dont know about soil, although many plants will remove dangerous metals from the earth and it goes into the building of the leaves However landfills are deep and plants have limits ,these places can be toxic for many thousands of years if not longer Polution being leached into subteranean water supplies forever as we are concerned . We are trying to make a gardening operation below what was Acapulco´s Dump 6 years ago and at times there are still dead fish way below in the streams I have used water hyacynth and other aquaric plants (with their leaves out and above the water) to clean small contaminated ponds ,with great succes Sorry but that is the exstent of my experiance.

Answer 3

I'm not sure plants can extract and clean up mercury for example. From time to time I have a client that buys a development site and our research indicates that the history of the site includes a petrol station.... now.. what we do in that instance is we rest the site for 5 years.. and then we remove/replace all the top soil to a depth of 1000mm .. and then re-test it. Now the top soil that is removed we hide somewhere cause nobody knows what to do with it.

shhh Please don't tell anyone but I think that soil over there has lead in it.

Answer 4

Phytoremediation is a name given to a set of technologies that uses different plants as containment, distruction, or an extraction technique. Yes it is possible to use to extract.