Different approaches have been used or developed to mitigate/reclaim the heavy metal polluted soils and waters including the landfill/damping sites and industrial effluent. Among these phytoremediation has got popularity due to low cost.
Different researchers suggests different plants for different heavy metals under the concept of phytoremediation. It is true that plant uptake heavy metals and make it part of its body. That plant or part of it is disposed off somewhere. But heavy metals will remain is heavy metals and transfer from one place into another. So where is mitigation?
Dear Nafees!
I believe that at the current situation phytoremediation cannot be used as a main remediation technique due to that concentrations of less than 100 mg/kg of different trace element (which is actually in some metals like Pb, Ba and others do not regarded as contamination) needs many years to be remediated. However, if this method could be developed in future then it could be promising. Metals uptake by plants could be recovered again using of course chemical methods but the most important thing in phytoremediation that it can be used in situ.
Regards
Yahya
Phytoremediation can avoid the high cost of soil disposal or other cleaning methods.
If you use energy crops (especially wood), incineration will decrease the mass of contaminated material (ash) to 1-3% of the original dry mass. It means you need to dispose a very small mass of hazardous material compared to the soil.
Managing the ash won't be any different if your energy crop from a contaminated or a clean site, ash always have a high metal content, so, you do not need a different infrastructure.
Phytoremediation also can avoid or reduce the spreading of heavy metals by influencing the water flows.
The main questions for choosing phytoremediation is the time we have and the risks (e.g. spreading, cause health or environmental problems). If we have plenty of time and low risks, it is a viable method.
If you consider ashing to decrease the mass and stabilise the contaminants, e.g. in concrete, please do not assume that no toxic volatiles will be produced during combustion
Phytoremediation is a technique that may be used not as a exhaustive way to solve the problem of soil contamination with potentially toxic elements, but as an tool for improving wastes management (the plants may be incinerated, and the less disposal requirements for a waste such as ash than for the contaminated soil). Of course, it should be considered additional pollution sources (such the one emphasized by Paul: toxic volatile compounds).
If you see the philosophy of treatment of waste, we are only changing the form of pollution.
It can not be completely treated. Wastewater is treated, sludge is produced, land pollution is created. Air pollutants are absorbed, water pollution is created. Solid waste are scientifically burnt air pollution is created and so on..
Similar is the case in Phyto- remediation the phyto- accumulation helps saying that heavy metals are reduced.
The treatment technology is basically pollution transformation process.
So to say Dr Nafees, you are right. Heavy metals are not removed from the earth. It is transferred from one place to the other.
I agree with Dr Sheth 's philosophy. The pollutant can not be completely removed from the earth.
I partially agree with Dr.Seth but the concentration of heavy metals in- situ is reduced to the soil. It also helps in reducing the groundwater quality contamination.
The concentration of heavy metals was be reduced to the soil so Phytoremediation helps in reducing the groundwater quality contamination but not in romoving pollutants from the soil.
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