SOURCES OF SILVER IN THE ENVIRONMENT

Silver is a naturally occurring metal that is extensively utilized in the photographic and imaging industry, as well as in electronics and e lectrical applications and other lesser uses. It is known to be discha rged to the environment from its industrial applications, and this lea ds to the possibility for exposure to aquatic and terrestrial organism s. Because of great differences in toxicity between silver compounds, the form in which silver enters the environment is important. While th e ionic form of silver has been shown to be toxic to a variety of aqua tic organisms, forms of silver other than ionic, or free, silver are s ignificantly less toxic. Ionic silver is known to convert to the more innocuous forms as it reacts rapidly with natural chemical ligands in sewer systems, sewage treatment facilities, and the environment. This paper reviews information on the industries that use silver, the quant ities they employ, and the forms and amounts of silver that may be dis charged from each into the environment.