Term
| the behavior of an element in the environment is dictated by... |
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Definition
| its valence and speciation in both the solid and solution phases |
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Term
| when redox status controls a given valence |
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Definition
| when the element is redox sensitive |
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Term
| trace element in soil concentration |
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Definition
| concentration less than 100 mg/kg |
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Term
| trace element in soil solution concentration |
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Definition
| soil solution concentration typically below 10-4 mol/L or below 10-6 mol/L |
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Term
| how trace elements may exist in the soil |
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Definition
-minor inclusions in minerals in soil
-rarely in discrete mineral phases |
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Term
| minerals in which trace elements may be substitutions or minor inclusions |
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Definition
-silicates and aluminosilicates
-hydrous metal oxides
-Fe sulfides
-Ca and Mg carbonates
-Ca, Fe, and Al phosphates
-may also reside in adsorbed phase or in association with soil organic matter |
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Term
| for any given element, the importance of each process in dictating fate and behavior will depend foremost upon ______, then upon ______. |
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Definition
oxidation state
solution and solid phase speciation within each oxidation state |
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Term
| an example of why oxidation state is important |
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Definition
| CrIII is a nonhazardous micronutrient, but CrVI is a toxin and a class A human carcinogen (by inhalation) |
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