Iron phases, amorphous hydrous

The adsorption of diphenylmercury (DPM) and phenylmercuric ion (PM) was studied on the solid phases described above (hydrous manganese oxides, amorphous iron oxides, humic acid and bentonite clay). The solid phase (5-15 mg) was added to 25-50 ml of filtered seawater yielding solid phase concentrations of approximately 100 to 400 ppm suspended matter. The concentration of seawater was also varied in order to study the variation of adsorptive behavior with changes in ionic strength. The suspension was then spiked with either DPM or PMA to yield concentrations of organometallic which varied from 0.10 to 3.5 ppm. The range in organometallic concentration used for this study was determined by the sensitivity of the detection method and the solubility of DPM and PMA in seawater. 

Sequential extraction procedures developed by Tessier etal. (1979) were applied to house dust and street dust by Fergusson and Kim (1991). Results indicated that most of the Pb (65-85%), Zn (70-95%), and Cd (60 -80%) was associated with the carbonate phase and the amorphous iron/ manganese hydrous oxide phases, but it was noted that the distribution of metals amongst different matrix components varied with proximity to different industrial sources. In another study, Zn was associated with the calcium-rich matrix, whereas Cd and Pb were associated with the silicon-rich matrix (Johnson et al., 1982). 

Environmental samples such as soils consist of multiple solid phases, which can be crystalline, poorly crystalline (or amorphous), or a mixture of the two. The solid phases may be coated in part by other crystalline or amorphous phases (e.g., hydrous aluminum, iron, or manganese oxides), natural organic matter, fungi, or microbial biofilms, and are always in contact with an aqueous solution and/or a gas, as discussed above. The contaminant or pollutant species in environmental samples are often at low concentrations (e.g., parts per million, ppm, or parts per billion, ppb), and are... 

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