Improved arsenic phytoextraction by combined use of mobilizing chemicals and autochthonous soil bacteria

• Published in: The Science of the total environment 2019-03, Vol.655, p.328-336
• Main Authors: Franchi, Elisabetta, Cosmina, Paola, Pedron, Francesca, Rosellini, Irene, Barbafieri, Meri, Petruzzelli, Gianniantonio, Vocciante, Marco
• Format: Article
• Language: English
• Subjects: Inorganic pollutants; Mobilizing agents; Phytoremediation; Phytotoxicity; Plant Growth Promoting Bacteria (PGPB); Soil contamination
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.11.242

Proper plant selection and application of suitable strategies are key factors to ensure the effectiveness of a reclamation via phytoremediation approach. In this study, micro- and meso-cosm scale experimentation has been realized to address a persistent contamination by arsenic on a disused industrial site through an assisted phytoremediation intervention. Three crop species, namely Brassica juncea, Helianthus annuus and Zea mays, have been considered and the addition of K2HPO4, a common mobilizing agent for As, or (NH4)S2O3, a promising additive for As mobilization in case of mercury co-presence, evaluated. The use of these additives significantly enhanced the bioavailability of the target contaminant and therefore its phytoextraction up to 80%. Furthermore, in order to maximize the extraction efficiency of the plants, the influence of five indigenous Plant Growth Promoting Bacteria (PGPB), in combination with the mobilizing agents, was measured. The addition of the microbial consortium led to a further increase in the total uptake of arsenic, especially in B. juncea (up to 140%). The combined strategy supports and enhances the arsenic phytoextraction together with an improvement of the soil quality, as shown by phytotoxicity tests. [Display omitted] •Plants alone are often ineffective to uptake heavy metals.•Soil amendments along with native bacteria inocula improved As phytoextraction.•Pot experiments showed that PGPB addition double arsenic content in roots.•The combined effect of phosphate and PGPB enhance As uptake in shoots.•Brassica juncea turned out to be the most effective with the largest uptake of As.