title: Is an adjusted rhizosphere-based method valid for field assessment of metal phytoavailability? Application to non-contaminated soils.
abstract: Previously recommended rhizosphere-based method (RHIZO) applied to moist rhizosphere soils was integrated with moist bulk soils, and termed adjusted-RHIZO method (A-RHIZO). The A-RHIZO and RHIZO methods were systematically compared with EDTA, DTPA, CaCl2 and the first step of the Community Bureau of Reference (BCR1) methods for assessing metal phytoavailability under field conditions. Results suggested that moist bulk soils are equally suited or even better than rhizosphere soils to estimate metal phytoavailability. The A-RHIZO method was preferred to other methods for predicting the phytoavailability of Ni, Cu, Zn, Cd, Pb and Mn to wheat roots with correlation coefficients of 0.730 (P<0.001), 0.854 (P<0.001), 0.887 (P<0.001), 0.739 (P<0.001), 0.725 (P<0.001) and 0.469 (P<0.05), respectively. When including soil properties, other extraction methods were also able to predict phytoavailability reasonably well for some metals. Soil pH, organic matter and Fe-Mn oxide contents, and cation-exchange capacity mostly influenced the extraction and phytoavailability of metals.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Fang
authors.forename: Bei
authors.initials: B
authors.lastname: Wen
authors.forename: Xiao-quan
authors.initials: XQ
authors.lastname: Shan
authors.forename: Jin-ming
authors.initials: JM
authors.lastname: Lin
authors.forename: Gary
authors.initials: G
authors.lastname: Owens
mesh_terms: D002104:Cadmium / Q000032:analysis; D003300:Copper / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D007854:Lead / Q000032:analysis; D008345:Manganese / Q000032:analysis; D008670:Metals / Q000032:analysis*; D009532:Nickel / Q000032:analysis; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D014908:Triticum / Q000378:metabolism*; D015032:Zinc / Q000032:analysis
chemical_list: D008670:Metals; D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D008345:Manganese; D003300:Copper; D009532:Nickel; D015032:Zinc