Silver speciation

The chronic aquatic effects which relate silver speciation to adverse environmental effects were studied on rainbow trout eggs and fry. The maximum acceptable toxicant concentration (MATC) for silver nitrate, as total silver, was reported to be 90—170 ng/L (43). Using fathead minnow eggs and fry, the MATC, as total silver, for silver thiosulfate complexes was reported as 21—44 mg/L, and for silver sulfide as 11 mg/L, the maximum concentration tested (27). 

Ferguson, E.A. and C. Hogstrand. 1998. Acute silver toxicity to seawater-acclimated rainbow trout influence of salinity on toxicity and silver speciation. Environ. Toxicol. Chem. 17 589-593. 

Although the abundance of silver in the Earth s crust is comparatively low (0.07 pgg-1), it is considered an environmental contaminant and is toxic at the nanomolar level. As an environmental pollutant it is derived from mining and smelting wastes and, because of its use in the electrical and photographic industries, there are considerable discharges into the aquatic environment. Consequently, there have been studies on the geochemistry and structure of silver-sulfur compounds [31]. Silver, either bound to large molecules or adsorbed on to particles, is found in the colloidal phase in freshwater. In anoxic sediments Ag(I) can bind to amorphous FeS, but dissolved silver compounds are not uncommon. A more detailed study of silver speciation in wastewater effluent, surface and pore waters concluded that 33-35% was colloidal and ca. 15-20% was in the dissolved phases [32]. 

Adams, N. W. H. and Kramer, J. R. (1999). Silver speciation in waste water effluent, surface waters, and pore waters, Environ. Toxicol. Chem., 18, 2667-2673. 

The extent of absorption of an administered dose of silver depends on silver speciation, the presence and extent of silver-binding proteins, and other variables. But absorption is dependent mainly on the transit time through the gastrointestinal tract the faster the transit time, the less silver is absorbed. Transit times ranged from about 8 h in mice and rats to about 24 h in monkeys, dogs, and humans. Route of administration affected the excretion rate of silver. Clearance of silver from mammals 2 days after silver was admmistered intravenously ranged... 

Chromium (total and speciated chromium) in chromium plated mists Colorimetric field method using 1,5-diphenyl carbazide after oxidation with silver (1 (-catalysed peroxydisulphate 67... 

Cadmium is a silver-white, blue-tinged, lustrous metal that melts at 321°C and boils at 767°C. This divalent element has an atomic weight of 112.4, an atomic number of 48, and a density of 8.642 g/cm3. It is insoluble in water, although its chloride and sulfate salts are freely soluble (Windholz et al. 1976 USPHS 1993). The availability of cadmium to living organisms from their immediate physical and chemical environs depends on numerous factors, including adsorption and desorption rates of cadmium from terrigenous materials, pH, Eh, chemical speciation, and many... 

Most measurements of silver concentrations in natural waters prior to the use of clean techniques are considered inaccurate. Until analytical capabilities that exceed the dissolved-particulate classification are developed, it will be necessary to rely on laboratory and theoretical modeling studies to fully understand chemical speciation of silver in natural waters (Andren et al. 1995). 

In aquatic environments, more research is needed on the chemical speciation of silver to evaluate risk to the organism and its consumers (USEPA 1987 Berthet etal. 1992). Most silver criteria formulated for the protection of aquatic life are now expressed as total recoverable silver per liter (Table 7.8), but total silver measurements do not provide an accurate assessment of potential hazard. Silver ion (Ag+), for example, is probably the most toxic of all silver chemical species and must... 

Berthet, B., J.C. Amiard, C. Amiard-Triquet, M. Martoja, and A.Y. Jeantet. 1992. Bioaccumulation, toxicity and physico-chemical speciation of silver in bivalve molluscs ecotoxicological and health consequences. Sci. Total Environ. 125 97-122. 

Lytle, P.E. 1984. Fate and speciation of silver in publicly owned treatment works. Environ. Toxicol. Chem, 3 21-30. 

Fortin, C. and Campbell, P. G. C. (2000). Silver uptake by the green alga Chlamy-domonas reinhardtii in relation to chemical speciation influence of chloride, Environ. Toxicol. Chem., 19, 2769-2778. 

LeBlanc, G.A., J.D. Mastone, A.P. Paradice, B.R Wilson, H.B. Lockhart, Jr., and K.A. Robillard. 1984. The influence of speciation on the toxicity of silver to fathead minnow (Pimephales promelas). Environ. Toxicol. Chem. 3 37-46. 

The first CE-ICP-MS coupled system was described by the Olesik group [100] for potential speciation studies. The need for an interface, with low dead volume to minimize peak broadening, was identified. In this interface, the capillary was grounded by coating 5 cm of the end with a controlled thickness of silver paint. The EOF was approximately 0.05 pL/min"1 however, the liquid flow rate increased, as a result of a vacuum effect from the nebulizer gas flow, which, in turn, resulted in a parabola-shaped velocity profile. This caused beak broadening to occur. 

Jenne, E. A., Girvin, D. C., Ball, J. W., and Burchard, J. M. Inorganic speciation of silver in natural waters - fresh to marine. Chapter 4, p. 41-61, Klein, D. A., ed., "Environmental Impacts of Nucleating Agents Used in Weather Modification Programs," 256 p. Dowder, Hutchinson and Ross, Stroudsberg, Pa. 1978. 

Silver L. A., Hunger P. D., and Stolper E. M. (1990) The influence of bulk composition on the speciation of water in silicate glasses. Contrib. Mineral. Petrol. 104, 142-162. 

---