Zinc speciation sediment

In natural waters, dissolved zinc speciates into the toxic aquo ion [Zn(H20)6]2+, other dissolved chemical species, and various inorganic and organic complexes zinc complexes are readily transported. Aquo ions and other toxic species are most harmful to aquatic life under conditions of low pH, low alkalinity, low dissolved oxygen, and elevated temperatures. Most of the zinc introduced into aquatic environments is eventually partitioned into the sediments. Zinc bioavailability from sediments is enhanced under conditions of high dissolved oxygen, low salinity, low pH, and high levels of inorganic oxides and humic substances. 

No information specifically related to transformation and degradation in sediment and soil was identified in the available literature. However, chemical speciation of zinc in sediment and soil is probably affected by the same factors affecting its fate in water. The sediment and soil chemistry of zinc are governed primarily by the pH and the physical properties of sediment and soil. In acidic... 

Environmental Fate. Zinc partitions to the air, water, and soil (Callahan et al. 1979 Guy and Chakrabarti 1976 Houba et al. 1983 Pita and Hyne 1975). Zinc occurs in the environment mainly in the +2 oxidation state (Lindsey 1979). Adsorption is the dominant fate of zinc, resulting in enrichment of zinc in suspended and bed sediments (Callahan et al. 1979). The mobility of zinc in soil has been characterized (Base and Sharp 1983 Bergkvist et al. 1989 EPA 1980d Hermann and Neumann-Mahikau 1985 Kalbasi et al. 1978 Saeed and Fox 1977 Tyler and McBride 1982). No estimate for the atmospheric lifetime of zinc is available. Development of pertinent data on the atmospheric processes important for zinc speciation in the atmosphere would be helpful. Development of this information would permit construction of a comprehensive model for the transport and interaction of zinc not only in air but in other media as well. Transformation in air and water can occur as a result of changes in chemical speciation (Anderson et al. 1988 Callahan et al. 1979 EPA 1980d Stokinger 1981). Data that describe the transformation processes for zinc in soil or the fate of zinc in soil are needed. A model of zinc flux from all environmental compartments would be useful for providing information on the overall environmental fate of zinc. 

Cordos, E.A., Frentiu, T., Rusu, A.-M. and Vatca, G. (1995) Elemental speciation of lead, zinc and copper in sedimented dust and soil using a capacitively coupled plasma atomic emission spectrometer as detector. Analyst, 120, 725-731. 

In soil research, the term speciation is often applied to operationally defined fractionation of heavy metals into five or more components.25 Typically, water soluble, exchangeable, organically bound (which includes what is in biomass), amorphous oxide bound, crystalline oxide bound, and residual fractions are measured.26 Sometimes residual fractions are further subdivided according to particle size distributions to give amounts in sand, silt, and clay fractions. Similar fractionation procedures are often applied to aquatic sediments.27 In arid regions, often the calcium carbonate bound fractions of heavy metals are also measured.28 Because of the constraints of detection limits, generally only cadmium, copper, iron, manganese, and zinc are usually monitored by flame spectrometry in such heavy metal speciation studies.28... 

Sigg, L., Kuhn, A., Xue, H. B., Kiefer, E., and Kistler, D. (1995) Cycles of Trace Elements (Copper and Zinc) in a Eutrophic Lake Role of Speciation and Sedimentation. n Aquatic Chemistry, C. P. Huang et al., Eds., American Chemical Society, Washington, DC. 

Speciation of zinc in mining wastes and contaminated soils. The molecular-level speciation of Zn(II) has been studied using EXAFS spectroscopy and other methods in contaminated stream sediments from the U S. Tri-State Mining District (O Day et al. 

Much of the literature on heavy-metal-bearing soils and sediments has been devoted to the speciation of anthropogenic metal(oid)s in contaminated matrices, but few papers focus on their crystal chemistry when they are present in trace amounts. This section reviews this topic and supplements and enhances the existing literature by describing the forms of arsenic, selenium, nickel, and zinc in two natural soils. It also attempts to illustrate with one example (Zn) how the novel synergistic use of pSXRF, pSXRD, and pEXAFS provides a quantitative analytical tool to speciate dilute multi-component metals in heterogeneous environmental materials. 

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