Soil, lead transformations within

The formation of humic substances in a peatland environment is a complex humification process which is principally due to certain enzymatic and microbial activities. These organic matter transformation processes are influenced by the nature of the peat-forming plants and certain physical and chemical properties within a particular peatland. In very acidic or low nutrient peatlands a very different microflora may exist than in a more eutrophic and less wet situation. In the former situation humification may be retarded and the peatland plants will be preserved and thus accumulate. On the other hand, in less acid environments with moderate amounts of nutrients and periodic water-table fluctuations humification proceeds relatively rapidly and leads to decomposed organic soils such is the case in drained and cultivated organic soils. 

Desorption on Metal Reduction Many bacteria and archaea can respire on Mn(lll/tV) and Fe(lll) oxides, leading to their dissolution, with the potential for concomitant displacement of arsenic into the aqueous phase (Cummings et al., 1999). In fact, within most soils and sediments, total As levels correlate with Fe content rather than Al or clay content (Smedley and Kinniburgh, 2002), and thus reductive dissolution—transformation of Fe(lll) phases should have a major impact on arsenic. Respiratory reduction of Fe in sediments generally occurs in zones where O2, NOs , and Mn(lV) [all being oxidants of Fe(ll) and alternative electron acceptors] are diminished (Lovley, 2000). 

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