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The Plant-Soil Interface: Soil Nickel Speciation and the Mechanisims of Nickel Hyperaccumulation.
11/22/05 1:21 PM
The ASA-CSSA-SSSA International Annual Meetings
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Tuesday, 8 November 2005
171-2
This presentation is part of: Symposium--Revisiting Metal Behavior in Biosolids Amended
Soils: Applying Knowledge Gained to an Understanding of Behavior of Metals in Soils
Systems: III
The Plant-Soil Interface: Soil Nickel Speciation and the
Mechanisims of Nickel Hyperaccumulation.
David Mcnear Jr., R. L. Chaney, and Donald Sparks.
We determined the effect of soil type (organic vs. loam) and liming on Ni speciation in soils surrounding an historic
Ni refinery and the influence of this speciation on Ni availability, translocation and storage in the Ni
hyperaccumulator Alyssum murale. Using a combination of analytical methods including SEM, micro-XAFS and
SXRF we found NiO, a direct byproduct of the refining process, present as discrete, spherical particles throughout
all of the soil types and treatments. Micro-XAFS enabled us to probe beyond the obvious NiO particles which
revealed that Ni was present as organic complexes in the organic soils, while in the loam soils Ni/Al layer double
hydroxide (LDH) and to a lesser extent Ni(OH)2 phases existed. There was little evidence for a significant effect of
liming on Ni speciation. This is the first study to directly identify LDH phases in whole, anthropogenically enriched
soils. It is hypothesized that the more soluble Ni species released from the refinery have since redistributed into
organically complexed phases (organic soils) or as secondary precipitates (loam soils) while the more resistant
NiO particles persist. We then determine the Ni compartmentalization, and identity of ligands responsible for Ni
transport and storage in the Ni hyperaccumulator Alyssum murale after which we discuss the connection between
soil Ni speciation and bioavailability.
See more of Symposium--Revisiting Metal Behavior in Biosolids Amended Soils: Applying Knowledge Gained to
an Understanding of Behavior of Metals in Soils Systems: III
See more of S02 Soil Chemistry
See more of The ASA-CSSA-SSSA International Annual Meetings (November 6-10, 2005)
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