s, particularly mercury
, but also arsenic
and others can have very toxic effects on living systems. Even copper
can be harmful in very large quantities, often replacing another atom
in a crucial configuration, thus inactivating or weakening it.
The ions of some of these heavy metals readily form ligands with organic molecules, tearing up the organic molecule very badly. In many cases, the ion is then free to wander off and rip up another, then another. This bull in a china shop effect is how the a seemingly small dose of a heavy metal can do a disproportionate amount of damage.
If the molecules thus deformed or denatured by the heavy metal ion happen to be crucial enzymes, neurotransmitters, RNA or proteins vital to life, the metal’s damage can be extremely harmful or fatal in short order.
Each heavy metal causes distinct toxicological effects. Lead can interact with enzymes and sulfhydryl groups and interferes with the production of red blood cells. Lead poisoning can cause catastrophic neurological deficits in children (adults too, but kids are at special risk).
Imperial (and Republican) Romans used lead for manufacture of water pipes (the word plumbing comes from the Latin root for the word lead, plumbum) and drinking goblets. More than a few historians have speculated that (at least some of) the ruin of the Roman Empire came from the toxic effects of these metals on the nervous systems of the rich and powerful Roman citizenry.
Cadmium salts or fumes may affect kidney function. Long-term exposure to the the metal may cause osteomalacia, as cadmium replaces the calcium in the bones, making them brittle. Others may cause dark lines in the gums and other mucosa. Most cause nausea, diarrhea and vomiting. Others can cause fevers, trembling, delirium, muscular weakness or a metallic taste in the mouth.
Many heavy metal salts are also powerful carcinogens, causing various forms of cancer from long-term buildup in the tissues. Heavy metals are a very serious problem in environmental pollution, as some food plants and animals can store the unwelcome substances in their tissues. This has been an ongoing difficulty with fish and shellfish, especially in the case of mercury and cadmium from industrial sources getting into the animals and then being ingested by humans.
Testing of the urine can usually quickly determine if a person has taken in a dangerous dose of a heavy metal. Heavy metal poisoning is often treated with a chelating agent such as ethylenediamine-tetra-acetic acid (EDTA). Such agent will form a chelate, a stable molecule bonded to the metal ions and thus prevent them from causing further harm. Such inactivated chelates are then filtered out by the kidneys and excreted.
Refs: the Dr. Joseph Smith Medical Library Online: http://www.chclibrary.org/micromed/00050500.html
Taber's Cyclopedic Medical Dictionary, 19th Edition (FA Davis, Philadelphia, 1997).
Also a song from the Styx album/performance piece/rock opera Kilroy Was Here. The piece entails the fanatical moralist Dr. Righteous (played by James Young) singing about how the culture of rock music has poisoned the young people and he intends to bring them back from their path of “sex, drugs and rock & roll”. As satire goes, it is a bit sloppy.
This song also contains a humorous attempt at backwards masking. At the time this was recorded, a number of parents' groups were very concerned about Satanic messages in rock albums being recorded bacwards into the track. Styx added the tongue-in-cheek message Annuit Coeptis. Novus ordo seclorum at the beginning of the song. These are, of course, from the dollar bill and roughly translates to "He has favoured our undertakings. A new order of the ages." I don't think the parents' groups got the joke.
Refs: Easter Eggs online: eegs.comhttp://www.eeggs.com/items/35379.html