Cobalt speciation and exchangeability in soils
(0) The environmental risk posed by cobalt (Co) contamination is largely a function of its oxidation state in soil and water. In its reduced form, Co<2+> simple salts and aquo-complexes are stable in aqueous solution but the presence of other ligands may promoteits oxidation to Co<3+> in solution. The objective of our work was to assess the potential biological availability of Co and the reactions and fate of soluble Co<2+> after addition to a range of soils with varying physical and chemical characteristics. We utilised an isotopic dilution technique using 57Co<2+> with high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) to determine the isotopically-exchangeable Co fraction in these soils. A potential problem in measurement of labile Co in soils using isotope dilution principles is the possible presence of two species of Co in soil solution and adsorbed on soil solid phases (Co<2+> and Co<3+>), coupled with the possibility that when an isotope of Co is added it may undergo conversion during the measurement phase to another oxidation state. No detectable Co<3+> was found in the aqueous extracts of the soils used;therefore, the pool of labile Co<3+> on soil solids was assumed to be negligible. Values for isotopically exchangeable Co <2+> in alkaline or Mn-rich soils appeared anomalously high, so we developed an isotopic desorption technique to correct for the potential oxidation and precipitation of 57Co<2+> by soil solid phases.
cobalt speciation bioavailability E values
Laura A. Wendling Jason K. Kirby Michael J. McLaughlin
CECR CSIRO Land and Water, PMB 2, Glen Osmond South Australia 5064, Australia
国际会议
第九届痕量元素生物地球化学国际会议(9th International Conference on the Biogeochemistry of Trace Elements)
北京
英文
1001-1003
2007-07-15（万方平台首次上网日期，不代表论文的发表时间）