To solid phase organic matter

Sorption of Neutral Organic Compounds from Water to Solid-Phase Organic Matter (POM)... 

It is very important to realize that only particular combinations of species in the numerator and denominator of complex KiA expressions like that of Eq. 9-16 are involved in any one exchange process. For example, in the case of dimethylaniline (DMA) (Fig. 9.2), exchanges between the solution and the solid-phase organic matter ... 

Retention of organic contaminants on subsurface solid phase constituents in general is not completely reversible, so that release isotherms differ from retention isotherms. As a consequence, the extent of sorption depends on the nature of the sorbent. Subsurface constituents as well as the types of bonding mechanisms between contaminants and the sohd phase are factors that control the release of adsorbed organic contaminants. Saltzman et al. (1972) demonstrated the influence of soil organic matter on the extent of hysteresis. Adsorption isotherms of parathion showed hysteresis (or apparent hysteresis) in its adsorption and desorption in a water solution. In contrast, smaller differences between the two processes were observed when the soils were pretreated with hydrogen peroxide (oxidized subsamples) to reduce initial organic matter content. The parathion content of the natural... 

Obviously, it is actually the total organic mass consisting of carbon, hydrogen, oxygen, nitrogen, etc. within the solid phase that acts to sorb the chemical of interest (i.e., the fom in kg om kg-1 solid). Natural organic matter is typically made up of about half carbon (40 to 60% carbon) hence, fom approximately equals 2-f and these two metrics are reasonably correlated. 

Figure 11.5 Dissolved and solid-phase shifts in concentrations of Fe, S, and P over different seasons and its relationship to changes in organic matter loading and redox in Rehoboth Bay (USA). (Modified from Rozan et al., 2002.)...

Many such studies of sedimentary phosphorus profiles, also incorporating pore water measurement of soluble reactive phosphate, have demonstrated that redox-controlled dissolution of iron (hydr)oxides under reducing conditions at depth releases orthophosphate to solution. This then diffuses upwards (and downwards) from the pore water maximum to be re-adsorbed or co-precipitated with oxidized Fe in near-surface oxic sections. The downwards decrease in solid phase organic phosphorus indicates increasing release of phosphorus from deposited organic matter with depth, some of which will become associated with hydrous iron and other metal oxides, added to the pool of mobile phosphorus in pore water or contribute to soluble unreactive phosphorus . The characteristic reactions involving inorganic phosphorus in the sediments of Toolik Lake, Alaska, are shown in... 

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