Aided-phytostabilization of steel slag dumps: The key-role of pH adjustment in decreasing chromium toxicity and improving manganese, phosphorus and zinc phytoavailability

Because of their high content in toxic metals, steel slag dumps are potential threats for the environment and public health. Among management methods that could mitigate hazard, aided-phytostabilization is a relevant, though challenging, option. Indeed, slags very unfavorable plant growth, due to metal toxicity alkaline pH (>10). In this work, we investigated how composted sewage sludge alleviate slag's while improving its nutritional status. A pot experiment was performed study biomass production leaf ionome composition five herbaceous species (Achillea millefolium, Bromus erectus, Festuca arundinacea, Melilotus officinalis Medicago sativa), relation soil pore water's pH, concentration trace major elements chemical speciation. Results showed had clear-cut effect on development. Above 8.6, severely affected, accumulation Cr above threshold deficiencies Mn, Zn P. Below increased significantly, together with decrease below level, an increase P deficiency levels. Thus, these results bring new insights into causes phytotoxicity allow considering aided-pytostabilization as realistic efficient approach remediation dumps, provided carefully monitored before seeding.