One of the primary problems is that what consitutes heavy metals is defined quite differently by different groups. For soap makers it is virtually any metal except sodium. For chemists it appears to comprise a block of all the metals in Groups 3 to 16 that are in periods 4 and greater which includes most metals, including silver and copper and iron.
But we are concerned with the definition as related to life sciences. That is, which ones give heavy metal poisoning if taken internally. For that it seems the the atomic weight of 200 is the key definition for this. See http://jchemed.chem.wisc.edu/Journal/Issues/1997/Nov/abs1374.html for information on this lack of a consistant definition. The transition metals are listed at: http://www.infoplease.com/periodictable.php?group=F Indeed, some ( definitions http://cancerweb.ncl.ac.uk/cgi-bin/omd?query=heavy+metals ) show copper zinc and iron as heavy metals, metals that are absolutely essential to life. Significant amoutns of iron are needed for the blood, so this definition is obviously wrong for trying to determine which metals are heavy metals associated with toxcitity. Marshall sol wrote: > That's ok, people seem to be mis-reading my intent, I do not need > arguments that silver is not toxic or that water can be toxic. I just > want to stop telling folks it is not a heavy metal, if in fact it is. > I have also read it called a "transition" metal, and the toxic heavy > metals are also listed as transition metals on the table I sent the > link to. I sh ould have researched this a long time ago, and not > parroted things I read. There is plenty of evidence that silver > (EIS) is not toxic without making false arguments, which is what I > want to avoid, as when I myself find out that a fact is mis-stated or > false, I tend to disbelieve everything else, you know? I simply want > to be accurate.paula > > ----- Original Message ----- > From: mamapug > > Even water is toxic in amounts > > large enough to drown in. Water can also be toxic > when swallowed in large amounts. Here in Utah, a > couple is up for murder, for forcing their adopted > child to drink quarts of water as a punishment.It > killed her. She was 5.Marshalee >
