Mobilities of Individual Trace Elements

In the following sections the biogeochemistries of important trace metals and metalloids in submerged soils are discussed. They are important either because of their redox chemistries or because they are particularly affected by soil redox 

For each element second row gives electron configuration, third gives elechonegativity and important oxidation states. 

Sources values calculated with Equation (4.8) using AG values from Garrels and Christ (1965). pe  

Zn + becomes strongly immobilized as solid solutions (van Breemen et al, 1980 Scharpenseel et al, 1983). The formation of [Ca,Mg,Zn]C03 solid solutions in submerged rice soils would explain the association between Zn deficiency and soils with high Mg Ca ratios. 

Like Zn, Cd is a Group IIB element and occurs in soils exclusively in the +2 oxidation state as the Cd + cation. Cadmium and zinc are often co-precipitated with each other in sulfide minerals in rocks (p/fCdS = 27.0). Hence Cd tends to be highly immobile under anaerobic sulfate-reducing conditions, but under acid, oxidizing conditions it is released in soluble and mobile forms. Hence soils 

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