kinetic control of the soil solid phase or soil solution. This knowledge
is critical for interpreting the results provided by different
pre-described speciation approaches (Manouchehri et al., 2011).
Owning to the complexity of physical and chemical interactions
in the soil, the modelling of TMs dynamic under natural environmental
conditions seems still to be out of the capacity of the most
recent methodologies. One way to try to avoid the complicated
complexation, desorption and readsorption of metals is to simplify
the metal desorption from the soil and its removal from the solution.
For this purpose, the desorption process could be considered
within a single extractive scheme using a single chemical complexing
agent and the removal process may be modelled using a sink
mimicking the metal uptake by the root membrane handled by a
chelating resin (such as DGT). In this way, a batch experiment of
soil/chelant/sink is proposed in the present work as a simple model
for mimicking the kinetics of soil/plant transfer. The kinetic regimes
of Pb, Cu and Cd are monitored in a batch system of soil,
EDTA (as the chelant) and Chelex (as the uptake sink). Contrary
to DGT technique (based solely on diffusive transport), both mechanisms
of metal transport from the bulk–soil to plant roots (mass
flow and diffusion) are considered in this approach. The kinetics
of desorption and removal processes will be also assessed in two
separate binary systems to determine the associated kinetic
parameters. The kinetic profiles of Pb, Cu and Cd are thereby assessed
in three systems: