Development and chromium uptake in hybrid poplars cultivated on substrate polluted with industrial slags

The report aims at improving knowledge of the interaction between poplar and heavy metals and at parsing the poplar ability to remove or render harmless such inorganic elements contained in residual slags of leatherindustries. Scions of Populus x euramericana, clone I-214, were grown outdoors, in pots, in inert soil, pruned for a single shoot and subjected to three treatments: non-amended (C), amended with a commercial mould (M), amended with tannery waste (W). The tannery waste consisted of a complex matrix composed of slags deriving from leatherprocessing and containing different amounts of heavy metals, particularly trivalent chromium. Non-destructive measurements were taken during one growing season; plant biomass and heavy metals content were analysed at the end of cultivation. Plants reared in the W soil developed stem length, leaf area and biomass significantly greater than those of the other treatments. Values of B, Mn, Fe, Zn and Cr in some of the vegetative organs also demonstrated that the clone I-214 uptakes significant amounts of these metals. According to the results, further studies should be planned to test both the toxicity risks of higher amounts of leather industry wastes and the phytoremediation ability of Populus x euramericana.