lead

Lead (chemical symbol Pb) is a toxic metallic element with no known biological function in humans.

Chemistry

Basic chemistry

Lead is one of the post-transition metals with the atomic number 82 and atomic weight 207.2. It is grayish in color and is pliable, poorly electrically-conducting with a high resistance to corrosion .

Radiochemistry

Four stable isotopes of lead account for virtually all of the lead on earth; lead-208 is the most abundant, forming 52.4%. Lead-206 and lead-207 form 24.1%  and 22.1% of the total respectively. Lead-204 constitutes the remaining 1.4%. Almost forty other radioactive lead isotopes are known, many with very short half-lives .

Toxicity

Unfortunately lead is a very toxic element, and lead poisoning or plumbism can have markedly negative outcomes on human health. In view of this toxicity its use has become increasingly restricted in much of the developed world, but unfortunately is less well-controlled in the poorer parts of the globe.

Its most devastating effects are on the CNS, although it is deleterious to every organ system .

Please see main article: lead poisoning.

Radiological importance

• shielding against ionizing radiation
  • key constituent both historically and contemporaneously

History and etymology

• Lead has been used extensively since ~7000 BCE . Its chemical symbol Pb is short for plumbum, the Latin word for lead. This is the origin of the word plumber and plumbing as lead has been widely used for water pipes in the home since Roman times . 

Siehe auch:

• Bleivergiftung

und weiter:

• generalized increased bone density in paediatrics