> Silver is NOT a heavy metal, and CS has never been shown to cause argyria. > Sigh... > Marsha
What is a heavy metal? "Turning to regular dictionaries (as opposed to chemical dictionaries): Webster (3) gives "A metal of high specific gravity; esp: a metal having a specific gravity of 5.0 or over." All the metals that I think of as heavy metals have densities above 5 g/cm3, while no metals with densities below 5 have heavy metal chemistry. This supports Webster's definition, but it is deceptive. Being a heavy metal has little to do with density, but rather concerns chemical properties. The metals that I have seen referred to as heavy metals comprise a block of all the metals in Groups 3 to 16 that are in periods 4 and greater. This seems to be a definition that should be generally useful. It may also be stated as the transition and post-transition metals." http://jchemed.chem.wisc.edu/Journal/Issues/1997/Nov/abs1374.html "heavy metal In the human health context, heavy metals are transition metal elements in the sixth and heavier periods, which should be present only in small quantities. Like lead Pb) and mercury (Hg), for instance. In microelectronics, heavy metals are period four and six transition metals that are troublesome contaminants because of their electrical properties. Au (see Gold) and Pt are lifetime killers in Si. Fe, Cu, Ni, and Cr, in period IV, have atomic weights in the range 51 to 63, or about twice that of Si. They're at the top of the famous curve of (nuclear) binding energy, so they're rather common. Because the conventional definitions include only transition metals, they exclude, amusingly, barium (Ba), whose name means heavy." http://www.plexoft.com/SBF/H01.html "The term heavy metal has apparently arisen as a convenience among policy makers for referring to metals with potential toxicity. Cadmium, mercury, lead and bismuth are often mentioned, partly because human activities have increased their concentration in the environment. Other metals are also associated with health problems. On the other hand, all are not, gold being an example because it cannot be easily absorbed by the body. Moreover, even light metals may cause health problems. A scientific definition of heavy metal might be based on whether a metal has a lower or higher density than its oxide. The dividing line in the periodic table will then go through titanium, which has several oxides, some of which are heavier and some lighter than pure titanium. Another approach defines heavy metal as one that has a density greater that 6.0 grams per cubic centimetre. Thereby, metals heavier than vanadium would be heavy metals, thus including most of the commercial metals." http://206.191.21.210/icme/q&as/qav5n4.htm ------------------------------------------------------------------------ -------- Hi Marsha, No point in dismissing the information, because the boffins and the politicians can't agree on a definition. CS has not been reported as causing argyria (so far as we know), probably because the amount ingested is much too low to do so. I don't recall the article suggesting that it did. Kind regards, Ivan. ----- Original Message ----- From: "Marsha Hallett" <[email protected]> To: <[email protected]> Sent: Saturday, 13 May 2000 03:29 Subject: Re: CS>Silver - an article > > > > This is a very interesting read. > > > > http://www.silverinstitute.org/news/bkhealthmet.html > > > > Ivan. > > Dear Ivan, Yeah, but this part bugs me: > "The removal of silver and other heavy metals is the function of the > metallothioneins. These ubiquitous proteins are found in all vertebrates and > invertebrates and act to transport, store, and detoxify essential and > nonessential trace metals. The metallothioneins chelate or agglomerate heavy > metals and convey them from the body. Their action can be overwhelmed by > ingestion of excessive amounts of heavy metals. In the case of silver, > excessive amounts may eventually deposit in the skin, giving it a gray > color. This deposit is called argyria and cannot be removed. > > Silver, being a highly conductive metal, has been shown to have a > deleterious effect in the presence of nerve cells. While heavy metals are > blocked from the nervous system and the brain by the blood-brain barrier by > a membrane whose purpose is to filter out heavy metals, certain stresses, > such as hypoxemia (the dangerously low level of oxygen in the blood that > occurs to some climbers at very high altitudes), may weaken this barrier." > > Silver is NOT a heavy metal, and CS has never been shown to cause argyria. > Sigh... > Marsha -- 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] Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <[email protected]>
