Hydrological control and phytoremediation by poplar and willow clones in a contamineted industrial site in Venice lagoon

The possibility to balance the rainfall by the evapotranspiration of a poplar and willow plantation has been investigated in an artificial Island of the Venice Lagoon (Isola dei Petroli) whose soil is contaminated with As, Cd, Pb, and Zn and surrounded by a deep insulating wall. One of the objectives was to individuate the best clones of the two Salicaceae (three poplars and willows) with the highest transpiration and extraction capacity of these metals. Further, the natural vegetation and a plantation of Pteris vittata were also evaluated for their ability to extract metals from the top soil.. Poplars showed higher tolerance to soil contaminants measured as the maintenance of a high photosynthesis-related parameters and transpiration rates per plant per day were also higher in poplars compared to willows. The plantation in short rotation density proved to be efficient in removing the rainfall available in the soil in excess of the field capacity during the vegetative season.