There is a lot of disagreement on this. Many dictionaries list any metal over a density of 50 as a heavy metal. That would make iron, copper and tin a toxic heavy metal, which is bordering on absurd.
Other references say an atomic weight 50 or higher, which also make tin, copper and iron heavy metals. It appears that someone writing these dictionaries did not know the answer so pulled numbers out of the hat. The best reference for the health side should be the EPA. Their site at http://www.epa.gov/ogwdw/Pubs/gloss2.html says: heavy metals. Metallic elements with high atomic weights, e.g., mercury, chromium, cadmium, arsenic, and lead. They can damage living things at low concentrations and tend to accumulate in the food chain. The exact same definition is given by Oak Ridge National Laboratory at http://risk.lsd.ornl.gov/homepage/glossary.shtml and http://www.environment-search.com/EnvDict.html http://www.marlin.ac.uk/Glossaries/Gen_Glossary.htm says: heavy metal A generic term for a range of metals with a moderate to high atomic weight, for example cadmium, mercury, lead. Although many are essential for life in trace quantities, in elevated concentrations most are toxic and bioaccumulate, and so are important pollutants. Gold and silver are not in any of those groupings. I looked at 6 chemistry books that I have on hand, and none of them even mention the term. :< Marshall "John A. Stanley" wrote: > In article <dav493pvtczdbfhg80p00005...@hotmail.com>, > "Ian Roe" <ian_onta...@hotmail.com> wrote: > >I talked with a pharmacist the other day and he told me silver was a heavy > >metal. Shows you how much he knows. The following site lists the > >transition metals if you ever have to show someone. > > > >http://www.chemicalelements.com/groups/transition.html > > I notice that the above website does not list a category called "heavy > metals". What exactly *is* a heavy metal? Does "heavy metal" have a > specific scientific definition? Is it a formal scientific classification > like "transition metal"? > > -- > John A. Stanley j...@natel.net > > -- > 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: > silver-list-requ...@eskimo.com -or- silver-digest-requ...@eskimo.com > with the word subscribe or unsubscribe in the SUBJECT line. > > To post, address your message to: silver-list@eskimo.com > Silver-list archive: http://escribe.com/health/thesilverlist/index.html > List maintainer: Mike Devour <mdev...@eskimo.com>
