title: Evaluation of soil metal bioavailability estimates using two plant species (L. perenne and T. aestivum) grown in a range of agricultural soils treated with biosolids and metal salts.
abstract: Few studies have quantified the accuracy of soil metal bioavailability assays using large datasets. A meta-analysis from experiments spanning 6 months to 13 years on 12 soil types, compared bioavailability estimate efficiencies for wheat and ryegrass. Treatments included biosolids ± metals, comparing total metal, Ca(NO₃)₂, EDTA, soil solution, DGT and free ion activity. The best correlations between soil metal bioavailability and shoot concentrations were for Ni using Ca(NO₃)₂ (r² = 0.72) which also provided the best estimate of Zn bioavailability (r² = 0.64). DGT provided the best estimate of Cd bioavailability, accounting for 49% of shoot Cd concentrations. There was no reliable descriptor of Cu bioavailability, with less than 35% of shoot Cu concentrations defined. Thus interpretation of data obtained from many soil metal bioavailability assays is unreliable and probably flawed, and there is little justification to look beyond Ca(NO₃)₂ for Ni and Zn, and DGT for Cd.
authors: Department of Soil and Physical Sciences, Faculty of Agriculture and Life Sciences, Lincoln University, Christchurch, New Zealand. amanda.black@lincoln.ac.nz
authors: Amanda
authors: A
authors: Black
authors: Ronald G
authors: RG
authors: McLaren
authors: Suzanne M
authors: SM
authors: Reichman
authors: Thomas W
authors: TW
authors: Speir
authors: Leo M
authors: LM
authors: Condron
mesh_terms: D000383:Agriculture; D004784:Environmental Monitoring / Q000379:methods*; D008129:Lolium / Q000378:metabolism*; D008670:Metals / Q000378:metabolism*; D012492:Salts / Q000378:metabolism; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000378:metabolism*; D014908:Triticum / Q000378:metabolism*; D014865:Waste Disposal, Fluid
chemical_list: D008670:Metals; D012492:Salts; D012987:Soil; D012989:Soil Pollutants