Page 40 - Plant-Based Remediation Processes

2 Protocols for Applying Phytotechnologies in Metal-Contaminated Soils 27

Fig. 2.3 Site-specific feasibility test: (a) microcosm, (b) mesocosm, (c) field test

– Microscale/Lab test (microcosm, Fig. 2.3a): at first the screening test to select
the most suitable plants and treatments and to verify eventually heavy toxic
effects of the contaminated matrices.
– Mesoscale/Greenhouse (mesocosm, Fig. 2.3b): the most effective protocols
(plant plus treatment) tested at the microscale are further investigated at a
more “realistic scale” as plants can grow to the end of their vegetative cycle in
bigger pots under controlled conditions (in a greenhouse). It allows for the
verification of the efficiency of a complete plant and moreover (as pots are
provided with leachate collectors) it is possible to check the mobility of
contaminants in soil core profile.
– Macroscale/pilot trials (lysimeter, field test, Fig. 2.3c): have to be carried out to
verify the performance of the protocols (plants plus treatments) selected from the
best performances observed during the mesoscale tests. This last stage allows for
the monitoring of plant growth biomass production and contaminants uptake
verifying how the local and specific site conditions can influence the
phytoremediation process. Moreover appropriate measures can be selected for
biomass treatment protection of the area. Uncertainty in the process should be
taken into account due to the uncontrolled weather conditions that cause diverse
plant response to stress (Tassi et al. 2011; Barbafieri et al. 2010; Barbafieri and
Raffaelli 2010).
During all test phases it is very important to monitor reduction of contaminants
from the soil as this is main critical success factor of the whole process. This
determination if often “forgotten” in scientific articles albeit that it reflects the real
effectiveness of the applied phytoextraction protocol. Few show the metal