Trace metals in natural waters

Buffle, J., Tessier, A., and Haerdi, W., Interpretation of trace metal complexation by aquatic organic matter, in Complexation of Trace Metals in Natural Waters, Kramer, C.J.M. and Duinker, J.C., Eds., Martinus Nijhoff/Dr. W. Junk Publishers, The Hague, 1984, pp. 301-316. 

Stolzberg [143] has reviewed the potential inaccuracies of anodic stripping voltammetry and differential pulse polarography in determining trace metal speciation, and thereby bio-availability and transport properties of trace metals in natural waters. In particular it is stressed that nonuniform distribution of metal-ligand species within the polarographic cell represents another limitation inherent in electrochemical measurement of speciation. Examples relate to the differential pulse polarographic behaviour of cadmium complexes of NTA and EDTA in seawater. 

Even if the solubility limit of relevant solid phases is not exceeded, a large fraction of trace metals in natural waters often occurs bound to particles of various size ranges (nanometres to millimetres). An important process for binding of metals to particles is adsorption to mineral surfaces (often oxides or hydroxides) [29]. 

Hart, B. T. (1982). Trace metals in natural waters. I. Speciation, Chem. Aust., 49, 260-265. 

Sigg, L., W. Stumm, and B. Zinder (1984), "Chemical Processes at the Particle/Water Interface Implications Concerning the Form of Occurrence of Solute and Adsorbed Species", in C. J. H. Kramer and J. Duinker, Eds., Complexation of Trace Metals in Natural Waters, Dr. W. Junk Publishers, The Hague, Netherlands, 251-266. 

Castilho, P. del, Gerritse, R.G., Marquenie, 3.M. and Salomons, W., 1984. Speciation of heavy metals and the in situ accumulation by Dreissena Polymorpha a new method. In C.3.M. Kramer and 3.C. Duinker (eds), Complexation of Trace Metals in Natural Waters. Nijhoff/3unk Publ., the Hague, pp. 445-448. 

Kramer, C.3.M. and Duinker, 3.C. (eds), 1984b. Complexation of trace metals in natural waters. Proceedings of the symposium, Texel, May 2-6 1983. Nijhoff/3unk Publ. The Hague, pp. 448. 

Stumm, W. and Bilinski, H., 1972. Trace metals in natural waters difficulties of interpretation arising from our ignorance on their speciation. In S.H. Oenkins (ed.), Advances on Water Pollution Research. Pergamon, New York, pp. 39-52. 

Current concern over the potential ecological impact of trace metals in the aquatic environment has led to extensive research in two main areas 1) the coordination chemistry of trace metals in natural waters and 2) the role of trace metals in the growth of aquatic organisms. Recent studies have shown that natural waters possess some capacity to complex metals and that this "complexa-tion capacity" can strongly influence the biological activity of a metal (1, ). Due to the presence of a diverse array of in-... 

Several imperfections remain, both in our understanding of the chemistry of trace metals in natural waters and in the sophistication of our experimental techniques, that prevent an exact determination of the thermodynamically available fraction ( oC pb , equation 4) and the electrochemically available fraction (Ij /I j, equation 11). The stability constants used in calculating the individual o"-values (equation 2) are subject to considerable uncertainty ( 2, 21, 42) and the conventional fj -values used in their adjustment to sea water conditions are based on a multiplicity of conventions. For many complexes that may be important in natural samples the stability constants are unknown and, frequently, the ligands have not been identified. 

Kramer C. J. M. and Duinker J. C. (1984) Complexation capacity and conditional stability constants for copper of sea and estuarine waters, sediment extracts and colloids. In Complexation of Trace Metals in Natural Waters (eds. C. J. M. Kramer and J. C. Duinker). Nijhoff/Junk, The Hague, The Netherlands, pp. 217-228. 

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