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Some materials are so commonplace that we take them for granted. One of those
materials is a grayish metal that has been with us for thousands of years. That metal is
lead,
still one of the world's most useful substances, and one that never ceases to find a role
in
human society.
Lead has the atomic symbol of Pb (for plumbum, lead in Latin). The
atomic number
for lead is 82 and the atomic mass is 207.19 AMU. It melts at about 327.502 oC and boils
at
1740 oC. Lead is a heavy, ductile, soft, gray solid. It is soluble in nitric acid and
insoluble in
water. It is found in North, Central and South America, Australia, Africa and Europe. In
modern times, lead has found a wide range of uses, and world demand for lead and its
products has steadily increased. Lead's usefulness stems from the metal's many desirable
properties: softness, high density, low melting point, ability to block radiation,
resistance to
corrosion, readiness to form alloys and chemical compounds, and ease of recycling. Its
versatility, as well as its physical and chemical properties, accounted for its extensive
use.
Lead can be rolled into sheets which can be made into rods and pipes. It can also be
molded
into containers and mixed with other metallic elements.
Lead was used in ancient times for making coinage, art objects and
water pipes. One
of the first known toxic substances, lead was used by the Romans for lining aqueducts and
in
glazes on containers used for food and wine storage; and it is suspected to have resulted
in
widespread lead poisoning. Members of the famous Franklin Expedition to the Northwest
Passage in the mid-1840s met a similar fate, being poisoned from lead in solder, widely
used
at the time to seal tins used to store foods. Until recently, one of the most significant
uses was
an anti-knock additive in gasoline. In the 1970s and 1980s, steps were taken to reduce the
use of leaded gas. By 1990, these actions had virtually eliminated the use of lead in
gasoline.
Lead is also one of the best and earliest examples of recycling about 55 percent of the
lead
used in Canada comes from recycled material.
One particular category of toxic tort is injury caused by exposure to
lead-based paint. The
hazards of lead-based paint have been known since the early 1900s, when the use of lead in
the
manufacture of paint was banned in Australia. The lead mining and lead pigment industries
in the
United States were able, however, to forestall the banning the use of lead in the
manufacture of paint
until 1978, when it (finally) became illegal in our nation. Lead poisoning occurs only
when too much
lead accumulates in the body. Generally, lead poisoning occurs slowly, resulting from the
gradual
accumulation of lead in the bone and tissue after repeated exposures. However, it is
important to note
that young children absorb 50% of a lead ingestion, while adults absorb only 10%.
The greatest risk of injury from lead poisoning is to children under
the age of seven, whose
developing bodies and brains are sensitive to even small amounts of lead, which can leave
children
with subtle but irreversible injury that does not appear until many years after the
exposure to lead. The
kinds of injuries lead causes in children include: learning disabilities, brain damage,
loss of IQ points
and intellect, academic failure, neuropsychological deficits, attention deficit disorder,
hyperactive
behavior, antisocial (criminal) behavior, neurological problems, encephalopathy (brain
swelling),
major organ failure, coma, and death. These injuries can be life-threatening or can
prevent a child from
realizing his or her scholastic, vocational, and financial potential, or from becoming a
self-sufficient
adult.
To confirm lead poisoning, the best test is a venous blood lead level.
If the blood lead level is
below 25 g/dL, then a serum ferritin level and other iron studies can be used to determine
if iron
deficiency anemia exists. With an elevated blood lead level of 50 ug/dL, the conclusion is
that the boy
is lead-poisoned. In this case, the child should be referred for appropriate chelation
therapy
immediately.
One particular category of toxic tort is injury caused by exposure to
lead-based paint. The
hazards of lead-based paint have been known since the early 1900s, when the use of lead in
the
manufacture of paint was banned in Australia. The lead mining and lead pigment industries
in the
United States were able, however, to forestall the banning the use of lead in the
manufacture of paint
until 1978, when it (finally) became illegal in our nation. Lead poisoning occurs only
when too much
lead accumulates in the body. Generally, lead poisoning occurs slowly, resulting from the
gradual
accumulation of lead in the bone and tissue after repeated exposures. However, it is
important to note
that young children absorb 50% of a lead ingestion, while adults absorb only 10%.
What we can do to prevent lead poisoning:
1. Do not burn lead debris.
2. Place lead debris in a six mil plastic bag.
3. For storage (of less then 48 hours), place storage bags in a secure area, away from
children and
animals.
4. Lead materials and debris must be transported in a covered vehicle to a lined municipal
landfill in accordance to state regulations.
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