title: Decrease in the genotoxicity of metal-contaminated soils with biochar amendments.
abstract: Biochar amendments, i.e., the solid product of biomass pyrolysis, reduce soil metal availability, which may lower the toxicity of metal-contaminated soils. A direct link between the decrease in soil metal availability and improved plant development is however often difficult to establish, as biochar may induce undesirable side effects on plant growth, e.g., a modification to plant nutrition. In order to investigate toxicity processes at a cellular level, roots of Vicia faba were exposed for 7 days to three metal-contaminated substrates and one control soil, amended with a 0 or 5% (w/w) addition of a wood-derived biochar. Exposure to pure biochar was also tested. Root tip cells were then observed to count the number of micronuclei as an estimation of DNA damage and the number of cells at mitosis stage. Results showed that biochar amendments led to a significant decrease in soil metal availability (Cd, Cu, Ni, Pb, and Zn) and to enhance root development on acidic substrates. The micronucleus frequency in root tip cells was positively correlated and the number of mitotic cells negatively, to the extractability of Zn in soils and to the concentration of Zn in secondary roots. Exposure to pure biochar caused a lower production of roots than most soil substrates, but led to the lowest number of observed micronuclei. In conclusion, biochar amendments can reduce the genotoxicity associated with the presence of metallic contaminants in soils, thereby potentially improving plant growth.
authors.affiliation: Laboratoire Sols et Environnement, Université de Lorraine, 54518, Vandœuvre-lès-Nancy, France.|INRA, Laboratoire Sols et Environnement, 54518, Vandœuvre-lès-Nancy, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Rees
authors.affiliation: Laboratoire Interdisciplinaire des Environnements Continentaux, CNRS UMR 7360, Université de Lorraine, 57070, Metz, France.
authors.forename: Adrien
authors.initials: A
authors.lastname: Dhyèvre
authors.affiliation: Laboratoire Sols et Environnement, Université de Lorraine, 54518, Vandœuvre-lès-Nancy, France.|INRA, Laboratoire Sols et Environnement, 54518, Vandœuvre-lès-Nancy, France.
authors.forename: Jean Louis
authors.initials: JL
authors.lastname: Morel
authors.affiliation: Laboratoire Interdisciplinaire des Environnements Continentaux, CNRS UMR 7360, Université de Lorraine, 57070, Metz, France. sylvie.cotelle@univ-lorraine.fr.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Cotelle
mesh_terms: D018533:Biomass; D002606:Charcoal; D019216:Metals, Heavy / Q000378:metabolism / Q000633:toxicity*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity*; D031307:Vicia faba / Q000187:drug effects* / Q000378:metabolism; D014934:Wood / Q000737:chemistry
chemical_list: D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; C540010:biochar; D002606:Charcoal
keywords: Bioassay; Biochar; Genotoxicity; Heavy metals; Micronucleus; Vicia faba