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Phytoextraction of urban sediments contaminated with cadmium and zinc: test of phosphorus fertilization

par Seguy, Vindiana
Président du jury Roisin, Yves
Promoteur Noret, Nausicaa ;Drouet, Thomas
Publication Non publié, 2023-09-04

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Résumé :

To decontaminate Cd and Zn-enriched road-deposited sediments (RDS), an innovativeand environmentally-friendly solution would be the use of an hyperaccumulator species capableof accumulating large quantities of TM in shoots, such as Noccaea caerulescens. Previousexperiments showed that growing N. caerulescens on RDS removes between 5.4% of Cd and10.5% of Zn annually. As RDS from Brussels are characterized by a high pH (>8) and a verylow P availability, the aim of this study is to investigate the potential effect of phosphorusfertilization on biomass production and thus, on the decontamination efficiency of thesesediments.The experiment was carried out in an open greenhouse from March to end June withtwo populations of N caerulescens, a metallicolous population from Southern France (METGAN)with a high Cd-accumulation capacity, and a non-metallicolous population fromLuxembourg (NMET-LUX) with a high Zn-accumulation capacity. Each population wasfertilized with two different types of phosphate fertilizers (superphosphate and dihydrogenophosphate)at different concentrations. For the di-hydrogenophosphate, two levelswere chosen: 40 an 80 mg kg-1 and three levels of SP were applied 40, 80 and 120 mg kg-1.Our results showed that plant growth was not improved by P fertilization treatments,despite the very low P availability of the substrate. However, we did observe a slightlysignificant improvement (11.2%) in cadmium concentration for the metallicolous population,with the superphosphate fertilization at a dose of 120 mg kg-1.The MET-GAN population achieved in four months 9.4% cadmium decontamination,while the NMET-LUX population achieved 2.9% zinc decontamination.