Speciation, metals

J. W. Novak, Jr., R. R. Burr, andR. Bednarik, "Mechanisms of Metal Ion Adsorption of Activated Alumina," Vol. 35, Proc. Int. Symp. on Metals Speciation, Separation, and Recorey, Chicago, lU., July 27—Aug. 1, 1986, Industrial Waste Elimination Research Center of the Illinois Institute of Technology, Chicago, lU. 

METHODOLOGICAL APPROACHES TO THE INVESTIGATION OF THE METAL SPECIATION IN THE NATURAL WATER... 

One of the characteristics of the cycle of metal mobilization and deposition is that the form of the metal is changed. This change in speciation of a metal has a profound effect on its fate. The link between metal speciation and fate is the central theme of this chapter. 

Table 15-6 Model results for metal speciation in natural waters ...

Recognition of the importance of metal speciation has had an enormous impact in the area of toxicity studies. Before this recognition, data were often difficult to interpret even from a single study, let alone from a range of investiga-... 

Mercury provides an excellent example of the importance of metal speciation in understanding biogeochemical cycling and the impact of human activities on these cycles. Mercury exists in solid, aqueous, and gaseous phases, and is transported among reservoirs in all these forms. It undergoes precipitation-dissolution, volatilization, complexation, sorption, and biological reactions, all of which alter its mobility and its effect on exposed populations. The effect of all... 

The full appreciation of the overriding importance of metal speciation in evaluating the transport and effects of metals in an environment is a relatively recent event. As more information is gathered on the forms in which metals exist and are transported through various environmental compartments, it will become possible to predict more accurately the response of the biological communities exposed to the metals and hopefully avert or mitigate the adverse effects. 

Meylan S, Behra R, Sigg L (2003) Accumulation of Cu and Zn in periphyton in response to dynamic variations of metal speciation in freshwater. Environ Sci Technol 37 5204... 

Fisher NS, Reinfelder JR (1995) The trophic transfer of metals in marine systems. In Tessier A, Turner DR (eds) Metal speciation and bioavailability in aquatic systems. Wiley, Chichester, p 363... 

Anodic stripping voltametry Applicable to few metals and dependent on metal speciation 10 to 10 ° M... 

Driscoll CT, Otton JK, Iverfeldt A. 1994. Trace metals speciation and cycling. In Moldan B, Cemy J, editors. Biogeochemistry of small catchments a tool for environmental research. Chichester, England J Wiley Sons, p. 299-322. 

Mass spectrometry can be specific in certain cases, and would even allow on-line QA in the isotope dilution mode. MS of molecular ions is seldom used in speciation analysis. API-MS allows compound-specific information to be obtained. APCI-MS offers the unique possibility of having an element- and compound-specific detector. A drawback is the limited sensitivity of APCI-MS in the element-specific detection mode. This can be overcome by use of on-line sample enrichment, e.g. SPE-HPLC-MS. The capabilities of ESI-MS for metal speciation have been critically assessed [546], Use of ESI-MS in metal speciation is growing. Houk [547] has emphasised that neither ICP-MS (elemental information) nor ESI-MS (molecular information) alone are adequate for identification of unknown elemental species at trace levels in complex mixtures. Consequently, a plea was made for simultaneous use of these two types of ion source on the same liquid chromatographic effluent. 

Table 8.80 shows the present status of speciation methodology. For trace-metal speciation, atomic absorption detectors feature a relatively high absolute detection limit (10 pg level), as compared to the 0.1 to 1 pg sensitivity level for molecular ion MS techniques as well as for MIP-AES. The detection limit of LEI-ToFMS is in the attogram range. Speciation has been reviewed [550]. Various monographs deal with speciation analysis [542,551,552]. 

Speciation analysis of organometal compounds by means of GC-MIP-AES and GC-ICP-MS has been reviewed [565], as has as metal speciation by HPLC... 

J. R. Kramer and H.E. Allen (eds), Metal Speciation Theory, Analysis and Application, Lewis, Chelsea (1988). 

H. De Beer, Metal Speciation by High Performance Liquid Chromatography, PhD. Thesis, Rand Afrikaans University, South Africa (1993). 

Effect of Medium Composition on Metal Speciation and Toxicity. 417... 

The interpretation of previous attempts at measuring the impact of metals on microbially mediated processes has been hindered by the use of a wide range of experimental conditions and measurements. Already, a shift from studies based on total metal concentration to those based on bioavailable metal concentrations has occurred. The next step will entail accurately predicting and measuring metal speciation patterns in order to identify microbial responses to metal speciation. Only then will it be possible to develop more effective methods to quantify and mitigate deleterious effects of metals on the myriad processes that microbes mediate in the environment. 

Hughes, M. and Poole, R., Metal speciation and microbial growth—the hard (and soft) facts, J Gen Microbiol, 137, 725-734, 1991. 

Navarro, R., Guzman, J., Saucedo, I., Revilla, J. and Guibal, E. (2003) Recovery of metal ions by chitosan sorption mechanisms and influence of metal speciation. Macromolecular Bioscience,... 

Howari F. Heavy metal speciation and mobility assessment of arid soils in the vicinity of A1 Ain landfill, United Arab Emirates Int J Environ Pollut 2004 22 721-731. 

Kheboian C., Bauer C. Accuracy of selective extraction procedures for metal speciation in model aquatic sediments. Anal. Chem 1987 59 1417-1423. 

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