The following excerpts should be of interest to all of you... ++++++++++++++++++++++++++++++++++++++++++++++++++++++= [Selected Excerpts]
Environmental Protection Compendium - British Columbia Ambient Water Quality Criteria for Silver February, 1996 Summary This document is one in a series that establishes ambient water quality criteria for British Columbia. ... "Criteria were not set for human, livestock or wildlife drinking water, recreational waters, irrigation water or industrial water uses, since, either suitable data documenting the effects of silver for these uses were lacking, or the criteria would have been about 1000 times higher than the aquatic life criteria and therefore redundant. Silver is most toxic to microscopic organisms or larval forms of aquatic animals. There is no evidence that silver is naturally transformed to a hazardous biologically-available form (such as mercury into methyl mercury). Ionic silver is more toxic to aquatic organisms than silver compounds." [BKS Note: Levels safe for aquatic insects and bacteria are recommended to be below 0.1uG/L] " ... Most toxicological studies have been conducted with silver in the free, elemental or 0 oxidation state, and with the +1 monovalent silver ion. The rarer +2 and +3 oxidation states have not been studied adequately. The majority of silver resulting from photo-processing occurs in an insoluble form. Theoretical calculations of organic and inorganic silver complexes indicate that, due to the low solubility of silver sulphide and the high affinity of silver for sulphide, little free silver would occur at equilibrium, in effluents or surface waters that contained any sulphide. Bioassays have demonstrated that, although 'free' silver caused the death of fathead minnows at relatively low silver concentrations, silver thiosulphate and silver sulphide salts had no effect at over 1000 times the 'free' silver concentration. The Aquatic Ecosystem Objectives Committee of IJC agrees that 'free' silver is a better measure of toxicity than total silver ...." Application of Criteria for Aquatic Life Silver is a disinfectant for non-spore forming bacteria at concentrations about 1000 times lower than the levels at which it is toxic to mammalian life. This extreme mammalian-to-bacterial toxicity differential is the definition of an oligodynamic material. The low concentration necessary for oligodynamic activity allows silver or one of its insoluble salts to be used indefinitely in contact with sterile liquids without silver levels building up to concentrations harmful to people. The biological effects of silver are apparently due to reversible bonds with enzymes and other active molecules on the surface of cells. Due to its sulphydryl binding propensity, biologically-available silver disrupts membranes, disables proteins and inhibits enzymes. The ionic form of silver is necessary for biological activity and the lipid phase of the membrane appears to be important in adsorbing silver ions to living cells. The active sites on enzymes which are affected by silver are apparently the electron-rich functional groups such as–SH groups. Silver combines with plasma proteins, is removed by the liver and over 90% is eliminated in the bile; most of this in the feces with very little in the urine. That silver which is not excreted is deposited in the skin and mucous tissues. Tissue deposition of silver results from precipitation of insoluble salts such as silver chloride and silver phosphate. These may be transformed to soluble silver sulphide albuminates and bind with amino or carboxyl groups in proteins and nucleic acids. They may also be oxidized to metallic silver by ascorbic acid or catecholamines. Argyria, silver deposition, occurs in all organs. Common deposition sites for people who have no history of therapeutic use are the liver, skin, pancreas, adrenals, glomeruli of the kidney, brain, bone marrow, walls of the blood vessels, thyroid, mesenteric glands, choroid plexus, spleen and testes. Generalized argyria is indicated by slate-gray skin and hair colouring, silver finger nails, a blue halo around the cornea and in the conjunctiva of the eye, disturbance of dark adaptation and turbidity of the anterior lens capsule. The tissue content and distribution pattern of silver deposition is a function of the intake route, quantity and chemical form. The discoloured skin in argyric patients exposed to ultraviolet radiation is likely caused by photoreduction of silver chloride to metallic silver, which is then oxidized to black silver sulphide and bound by tissues. If the diet is high in selenium, the silver sulphide is converted to silver selenide which may result in higher silver deposition rates than with silver sulphide. The full document from which this information is extracted can be found at: http://www.env.gov.bc.ca/epd/cpr/criteria/awqcfs.html ================================================================= The above is particularly relevant to the salt / no salt discussion, and in reguards to the statements that pure, positively charged silver ions are the most effective form of silver we can use against bacteria / pathogens (rather than compounds.) You may wish to archive this info & bookmark the site for future reference. [Grin] Be Well! Bruce K. Stenulson Applied Technology The Alternate Health Approaches Forum http://web.idirect.com/~showcase/althealth -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the subject: line. To post, address your message to: [email protected] List maintainer: Mike Devour <[email protected]>
