title: Evaluation of extractants for estimation of the phytoavailable trace metals in soils.
abstract: Despite its environmental (and financial) importance, there is no agreement in the literature as to which extractant most accurately estimates the phytoavailability of trace metals in soils. A large data set was taken from the literature, and the effectiveness of various extractants to predict the phytoavailability of Cd, Zn, Ni, Cu, and Pb examined across a range of soil types and contamination levels. The data suggest that generally, the total soil trace metal content, and trace metal concentrations determined by complexing agents (such as the widely used DTPA and EDTA extractants) or acid extractants (such as 0.1M HCl and the Mehlich 1 extractant) are only poorly correlated to plant phytoavailability. Whilst there is no consensus, it would appear that neutral salt extractants (such as 0.01 M CaCl(2) and 0.1 M NaNO(3)) provide the most useful indication of metal phytoavailability across a range of metals of interest, although further research is required.
authors.affiliation: School of Land and Food Sciences, The University of Queensland, St. Lucia, Qld 4072, Australia.
authors.forename: Neal W
authors.initials: NW
authors.lastname: Menzies
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Donn
authors.forename: Peter M
authors.initials: PM
authors.lastname: Kopittke
mesh_terms: D001682:Biological Availability; D002104:Cadmium / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003300:Copper / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics; D004492:Edetic Acid / Q000737:chemistry; D006851:Hydrochloric Acid / Q000737:chemistry; D007854:Lead / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics; D019216:Metals, Heavy / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics*; D009532:Nickel / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics; D004369:Pentetic Acid / Q000737:chemistry; D018517:Plant Roots / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism; D010944:Plants / Q000378:metabolism*; D012492:Salts / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics*; D015032:Zinc / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics
chemical_list: D019216:Metals, Heavy; D012492:Salts; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D003300:Copper; D004369:Pentetic Acid; D009532:Nickel; D004492:Edetic Acid; D015032:Zinc; D006851:Hydrochloric Acid