Page 31 - Curriculum Visions Dynamic Book

Lead poisoning
From ancient times, pottery workers were known to suffer from lead poisoning because of breathing in lead fumes and handling lead glazes. At the beginning of the 20th century, lead was so widely used for industrial processes that researchers found 77 occupations at risk from lead poisoning. Such evidence began to make protection from harmful substances seem necessary.
Lead is absorbed very slowly. Unfortunately,
the body has no natural way of getting rid of any lead that is absorbed, so any lead taken in as fumes or in food, or in liquids, simply builds up in the body, especially in the liver and kidneys.
People suffering from lead poisoning lose their appetite, start to be sick and may develop convulsions. In severe cases the brain is damaged and death
may follow.
The most important sources of lead poisoning
are thought to be caused by lead in some drinking water supplies (especially in soft-water areas) and in vehicle exhausts.
Studies show that children are particularly vulnerable to lead poisoning. This knowledge has resulted in the replacement of lead with copper water pipes, the removal of lead from domestic paints and the change from leaded to unleaded fuel.
EQUATION: How lead dissolves in water
Lead + soft water + dissolved oxygen ➪ lead hydroxide 2Pb(s) + 2H2O(l) + O2(g) ➪ 2Pb(OH)2(aq)
radiation: the exchange of energy
with the surroundings through the transmission of waves or particles of energy. Radiation is a form of energy transfer that can happen through space; no intervening medium is required
(as would be the case for conduction and convection).
radioactive: a material that emits radiation or particles from the nucleus of its atoms.
X-rays: a form of very short wave radiation.
Lead protects the body
from radiation
X-rays, which are produced when charged particles collide, are a form of radiation whose waves have a much shorter wavelength than that of visible light.
How well X-rays can pass through a material depends on the density of the atoms of the material. Bones, for example, are very dense and block most radiation, and this is what causes their X-ray image to appear white. Tissue blocks less radiation and appears darker on the film. Lead is composed of large, closely packed atoms that will absorb all X-rays.
One common use of lead is therefore as a shield against radiation, for example, to protect those who make X-ray pictures in hospitals and dental surgeries. It is also used in nuclear power stations and in the containers used to transport radioactive materials.
 Lead is made of closely packed large and heavy atoms. This makes it very difficult for radiation to pass through it.
Lead shield
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