TABLE 4-2 Rankings of Bioavailability Tools According to Seven Criteria

Technique

Application to the Field

Application to Solid Phase

Single vs. Lumped Processes

Physical/chemical characterization of the solid phase

General characteristics

• Organic carbon content

• Particle/grain size

• pH

• CEC

• HA/FA

2

Can test field samples in the laboratory.

3

Directly relevant to solid phase in situ; necessary to understand solid phase reactions.

2

Measures are the outcome of lumped processes, but can be used to interpret single processes.

Specific structures

• Characterization of carbonaceous and other solid phases using NMR, petrography, EA, IR/FTIR.

2

Can test field samples in the laboratory.

3

Directly measures the solid phase.

2

Determines nature of the phase but not contaminant-phase interactions.

Specific forms of contaminant bound to solids

• XRD and SEM

• XAS

• μL2MS

• SIMS

• NMR

• EPR

• XPS

2

Some methods hard to use on natural particles. Detection limits of equipment can cause problems in natural settings.

3

Directly applicable to solid phase.

3

Uniquely suited to identify mechanisms of association.

Extraction of soils and sediments for inorganic contaminants

Extracts that change the solid phase

• Conventional

• Sequential

• TCLP, SPLP

2

Can extract field soils and sediments, but must remove from field for test.

2

Concentration extracted is qualitatively or operationally related to associations (form) in the solid phase.

1

Operational measure that lumps different association/dissociation processes.



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