You can only translocate all elements (including heavy metals) not let them disappear.

You can not destroy elements but transfer these from highly polluted places to some other places where solid waste disposal system is available. But that might not be a cost effective approach. I have a very recent publication on this topic of disposal of phytoaccumulated plants after processing via vermiremediation.

Please go through my profile and you can download that article. The idea of that work was to use those phytoaccumulated water hyacinth plants as a source of vermicompost where earth worms feed on these and produces organic matter in chelation form restricting those heavy metals to the compost system and not let these to become bioavailable.

According to some researchers plants act both as " accumulators" and "excluders". Accumulators survive despite concentrating contaminants in their aerial tissues. They biodegrade or bio-transform the contaminants the contaminant into inert forms in their tissues. The excluders restrict contaminant uptake into their biomass. Plants have also evolved highly specific mechanisms to translocate and store micronutients. These same mechanisms are also involved in the uptake, translocation and storage of toxic elements, whose chemical properties simulate those essential elements. Thus micronutrient uptake mechanisms are of great interest to phytoremediation. For more details consult https;//dx.doi.org.10.1155/2011/939161

its the new future project for me, Azolla plants have the ability to remove heavy metal from water and environment (green or dried)

Thanks to you all. I really appreciate.

For more safety, the heavy- metals can be furtherly degraded or make it less bioavailable and then disposed. Heavy metals like Zn3+ can be converted to Zn which is required by plants as an essential micronutrient.