Remobilization trace metal

Saulnier, I. Mucci, A. 2000. Trace metal remobilization following the resuspension of estuarine sediments Saguenay Fjord, Canada. Applied Geochemistry, 15, 191-210. 

However, only the smallest part of soluble metals is involved in the biological cycle. Most of these are either lost to water runoff, or retained in the peat organic matter. The latter is the source of gradual remobilization but the whole mineralization may last up to 50 years or even more. The total accumulated retained amount of macro-or trace metals in organic matter of peat is tens and hundreds of time higher than the concentration of annually released soluble forms, which are available for plants. 

When sediment porewaters become depleted in oxygen, Fe and Mn are reduced and mobilized to the dissolved phase. If the sediments are anoxic sufficiently near the sediment-water interface so that the dissolved reduced ions diffuse to the overlying water before they are reoxidized, the sediments become depleted in the concentration of Fe and Mn. This process creates regions where sediments are strongly Mn-depleted, but it has a much smaller influence on Fe because of its very rapid oxidation kinetics. Trace metals that are strongly associated with the Mn oxides in the particulate phases (e.g. V) are also remobilized to the bottom water in these areas. 

Sawlan, W. Murray, J.W. (1983) Trace metal remobilization in the interstitial waters of red clay and hemipelagic marine sediments. Earth Planet. Sci. Letters 64,213-30. 

Estimation on the remobilization of metals under changing environmental conditions and on the potential uptake by biota are two major objectives of species differentiation on particle-bound trace metals. However, many authors have shown that with respect to bioavailability, as distinct from geochemical mobility, the present state of knowledge on solid matter speciation of metals is still somewhat unsatisfactory. The... 

Biological activities are typically involved in these processes remobilization of trace metals has been explained by the removal of sulfide from pore waters via ventilation of the upper sediment layer with oxic overlying water, allowing the enrichment of dissolved cadmium that would otherwise exhibit very low concentrations due to the formation of insoluble sulfides in reduced, H2S-containing sediments. Emerson et al. 

A debate has taken place about whether it is remobilization or reduced capture that has led to elevated dissolved trace metal concentrations in lakes (e.g., Norton Hess,... 

Sinking particles transport trace elements to the sediments. Once in the sediments, chemical reactions can resolubilize a significant fraction of the particulate metals. This process is termed diagenetic remobilization and is the subject of the next chapter. The resolubilized elements can diffuse across the sediment-water interface into the deep zone. 

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