Heavy metal phytoremediation of a poplar clone in a contaminated soil in southern Italy

Abstract

BACKGROUND The Monviso clone previously tested successfully to remediate a lindane‐contaminated soil in central Italy was then applied in a historically heavy metal contaminated area in southern Italy. RESULTS The results obtained at 900 days from the poplar planting showed a strong decrease below Italian national legal limits (D.Lgs 152/06) for most heavy metals (HMs). The highest reduction of HM concentrations was observed in soil samples collected near the trunk (25 cm distant from poplar) and in the rhizosphere. The values of the HM bioaccumulation factor (BAF, considering roots and leaves) and of the translocation factor (TF) suggest that poplar trees were able to phytostabilize HMs. The soil organic carbon content increased compared to the previous sampling in all plots planted. The highest values were observed for the rhizosphere soils of each target tree, while the phosphorous available strongly decreased. Microbial results showed an overall increase in cell viability, dehydrogenase activity and microbial abundance of some bacterial groups. CONCLUSION Overall results showed that the poplar‐based phytoremediation strategy was able to promote the phytostabilization of the HMs and to improve the soil quality in terms of both organic carbon content and microbial community structure and activity. © 2019 Society of Chemical Industry

Characterization of the belowground microbial community in a poplar-assisted bioremediation strategy for restoring a multi-contaminated soil

“…sugars, polysaccharides, amino acids, aromatic acids, aliphatic acids, fatty acids, sterols, phenolic compounds, enzymes, proteins, plant growth regulators and secondary metabolites) which attract soil microorganisms into the rhizosphere where they multiply by several orders of magnitude [28]. In turn, microorganisms strongly in uence plant development and health by mineralizing organic matter, degrading organic pollutants, including persistent ones such as PCBs, improving heavy metal bioavailability by varying the degree of reaction of the soil (pH), releasing chelating substances (organic acids, siderophores) and promoting oxidation/reduction reactions [8,20]. In line with the above, the DNA sequencing data showed higher percentages of bacteria genera (i.e.…”

“…Heavy metals (HMs) are "trace elements" in pristine ecosystems, whereas their concentrations increase when there are anthropogenic activities (steel industry, waste disposal, agriculture, mining). HMs pose a risk owing to their toxicity, bioaccumulation and biomagni cation [4]; they cause cell oxidative stress through formation of free radicals and are able to replace essential metals in pigments or enzymes, with consequent disruption of their functions [5,6]. PCBs and HMs are frequently found as soil cocontaminants [7,8], posing a risk for both ecosystems and human health.…”

“…The complex and synergistic actions established in the rhizosphere between the tree root system and natural belowground microbiota make it possible to remove, convert or contain toxic substances in soils [18,19,20]. Our recent research has shown the ability of the hybrid poplar genotype Monviso (Populus generosa x Populus nigra) to grow in a nutrient poor soil, resisting high metal concentrations and promoting PCB biodegradation in the rhizosphere in a chronically polluted area [8,21].…”

In Focus: 7th European Bioremediation Conference (EBCVII)

“…The elimination of heavy metals from soil and the improvement of its quality was also the main objective of another paper by Ancona et al, who presented a poplar-based phytoremediation method. 6 This work highlighted a specific plant species that favours the phytostabilization of heavy metals, as a consequence of complex interactions generated between the plant and the rhizosphere microorganisms. The result is an overall improvement of soil quality in relation to organic carbon content and microbial activity.…”

“…Upon investigating various operational conditions, authors concluded that those bacteria may actually protect plants with a simultaneous decrease in metals accumulation. The elimination of heavy metals from soil and the improvement of its quality was also the main objective of another paper by Ancona et al ., who presented a poplar‐based phytoremediation method . This work highlighted a specific plant species that favours the phytostabilization of heavy metals, as a consequence of complex interactions generated between the plant and the rhizosphere microorganisms.…”