Project Number: 8042-12000-041-05-R
Project Type: Reimbursable
Start Date: Aug 1, 2013
End Date: Jul 31, 2015
Soils with nickel (Ni) contamination (mining, smelting, other industrial contamination) or naturally high Ni concentration can cause Ni phytotoxicity when soils are acidic and contain low levels of clay, Fe and Mn oxides or organic matter which normally adsorb soil Ni and reduces Ni phytoavailability to plants. Plants vary widely in susceptibility to Ni phytotoxicity. Consideration of soil chemistry, soil fertility, chemical/physical forms of Ni present, plant species, and concentrations in Ni in plant tissues allows identification of Ni phytotoxicity requiring remediation. Consideration of soil properties and remediation goals identify soil amendments needed to remediate the potential for Ni phytotoxicity. Usually limestone applications can support normal plant growth, but some contaminated soils have become deficient in one or more nutrients and require addition of fertilizers as well as liming agents. New methods to hasten formation of insoluble nickel aluminum (Ni-Al) layered double hydroxide compounds in soil can aid in soil Ni remediation. In addition to in situ remediation using soil amendments, it is possible to use phytoextraction of Ni using Ni hyperaccumulator plant species grown as a phytoextraction crop. Phytoextraction generates crop biomass which can be used as a Ni ore. The planned review will provide information that will assist the Cooperator's members plan and achieve remediation of problem Ni contaminated soils.
A literature review will be conducted of cases of nickel contamination of soils and methods for remediation of Ni contaminated soils. ARS will identify soil properties which promote or reduce Ni phytotoxicity and soil amendments which can strongly reduce the potential for Ni phytotoxicity for sensitive plant species. Fundamental causes of Ni phytotoxicity in relation to soil properties and solubility of Ni ions in soils will be summarized. Examples of using the analysis of causes of Ni phytotoxicity and use of soil amendments to alleviate Ni phytotoxicity will be summarized. A systematic approach to soil and plant analysis to diagnose Ni phytotoxicity will be developed. In addition, present status of Ni phytoextraction and phytomining will be summarized as another method for remediation of Ni phytotoxic soils. As with most areas of research, only part of the literature on Ni in soils and plants is now understood to be relevant to the understanding of practical Ni phytotoxicity. Factors which influence the solubility of Ni in soils, and factors of contaminated soils which interact with Ni loading to influence phytotoxicity will be summarized. The mechanism of soil Ni-induced phytotoxicity will be summarized where it is known. The mechanisms by which soil amendments can persistently alleviate Ni phytotoxicity will be reviewed and applied to development of recommended remediation practices. The potential for Ni phytoextraction to support soil remediation by NiPERA organizations will be summarized. Current best management practices for Ni phytoextraction will be summarized, and approaches to the use of phytoextraction in practice for soil remediation will be summarized.