Hello community
Once a process of phytoremediation has been completed, the herbaceous and / or shrubs maintain a high content of heavy metals or other pollutants, the question is addressed to how can these be exploited? How can they be processed so as not to return these metals to the environment?
Thank in advance
Regard
Hello,
As you know the total content of heavy metals (HM) can not be destroyed so the the possible way to stop that HM content accumulated in any plant tissue system getting reverted back to the environment is to process those plant samples. I have done a similar kind of experimentation considering arsenic and water hyacinth as phytoaccumulator. The way to stop such process is, using those HM accumulated plants as a source of vermicomposting. During the production of vermicompost, earthworms produces some amino acid based chemicals known as phytochelatin that strongly binds to the HM and make a chelate to the soil fractions and this won't let the HM to get released easily to the soil environment. for details of this process please check out my paper as below-
Article Vermiremediation of metal(loid)s via Eichornia crassipes phy...
As another option the HM accumulated plants can be dumped in any engineered constructed waste landfill where the groundwater aquifer is far below from the percolation range in short time span. This might allow to get HM stored in a concentric place and not dispersed in a whole area.
Thank you
Thank Arnab for you quick respons, I will read your article, discuss it later?
Thanks for everything
Hi Jorge,
Let me preface this answer by saying I am by no means an expert on phytoremediation but I do have quite a bit of experience in microbial bioremediation of toxic metals.
As far as my experience goes working with metals in the mining industry, one of the bottleneck of phytoremediation is indeed the cost of processing metal-laden plants and managing contaminated sites long term. Although this is not the most glamorous approach, combusting the biomass and scrubbing the CO2 that emerges is used in the context of smelting so that the metals accumulated can be recovered to potentially offset the cost of remediation.
Really, the hope with phytoremediation is the metals, which can also serve as nutrients, stay locked within plant biomass rather than mobile in soil but that does not preclude them from getting into the food web. This also depends on the metals of interest (e.g. physiologically important or not, there is a big difference between immobilizing something like mercury, which does not help plants grow vs copper which is an essential nutrient). Perhaps offering some clarification on this will help people answer your question.
Hope this helped,
Daniel
One way is to dry and incinerate the biomass. Depending on the kind of metal you are dealing with you can proceed by extracting the metals from the ashes. The heath generated by the incineration can produce energy..
As an example, depending on the level of contamination Streptanthus polygaloides is able to extract 1,5 - 4,8 mg of nickel per gr. of dried plant this represents up to 100 kg of nickel per ha.
One of teh issues you need to bear in mind with phytoremediation is that the plants will only sequester the bioavailable fraction of the HM contaminants. Recommend that you check out CL;AIRE - Contamianted Land Applications In Real Environment you will find this UK site is a wealth of information and resources on contaminated land and details the UK approach and a huge range of guidelines.
As mentioned by Jean-Pierre Jost above most biomass generated from phytoaccumulators tends to be burned. A lot of large phytoremediation projects have failed (eg Ravenscraig, Motherwell, Scotland) and conventional remediation (cap and build) was then applied.
You also need to then consider whether the heavy metal loading in the biomass will be concentrated into the ash (it will be). In europe that means doing a full analysis and determining the metal concentration of the ash to esnure it doesnt have metal levels above any of the waste thresholds for disposal.
Dear Campos
I have published a excellent review paper entitled" Mechanistic understanding and holistic approach of phytoremediation: A review on application and future prospects" at Elsevier publishing in Ecological Engineering. I think solve your every questions
Please see the given below attachment.
Article Mechanistic understanding and holistic approach of phytoreme...
Krishna
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