Silver and Gold

Abstract

Silver and gold are transitional metals exhibiting very different chemical and toxicological properties. Apart from their precious metal value and use in coinage, each has distinctive uses in industry, commercial applications, and medical devices. The World Health Organization and various national regulatory authorities recognize that like many other metals, silver and gold can pose significant health risks through occupational exposure in mining and industrial processes. Nowadays, with the increasing use of nanoparticulate materials with increased biological activity, other toxicological risks are encountered. Thus, gold dust is an environmental contaminant in the vicinity of mining areas, but in view of its high density, particles settle rapidly, thereby reducing the hazards of inhalation by workers. Gold miners are at greater risk through exposure to silica dust, mercury vapor, radon, and cyanide. The principal risks associated with chronic exposure to silver include argyria and argyrosis leading to profound discolorations of the skin and eyes. Unregulated use of colloidal silver presents an ongoing risk. Both silver and gold exhibit allergenic properties. Selected clinical cases are documented to illustrate specific toxicological complications encountered with both metals. Analytical methods currently available for the determination of silver and gold complexes in blood and other tissues following clinical or occupational exposure provide a means to understanding absorption and metabolism. The present chapter discusses chemical properties of the metals, their mining and extraction, and human exposure. Epidemiological studies provide a broad understanding of the safety of these metals and their compounds in clinical and occupational exposures.