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What Makes Lead Poisonous
By Anne Marie Helmenstine, Ph.D.
People have been using lead in
their daily lives for a long time.
The Romans made pewter dishes
and pipes for water from lead.
While lead is a very useful
metal, is also poisonous.
The effects of poisoning from
lead leaching into liquids may have contributed to the fall of the Roman
empire.
Lead exposure didn't end when
lead-based paint and leaded gasoline were phased out.
It is still found in the
insulation coating electronics, leaded crystal, storage batteries, on the
coating of some candles wicks, as certain plastics stabilizers, and in
soldering.
You are exposed to trace
amounts of lead every day.
What Makes Lead Poisonous
Lead is toxic mainly because
it preferentially replaces other metals (e.g., zinc, calcium and iron) in
biochemical reactions.
It interferes with the
proteins that cause certain genes to turn on and off by displacing other metals
in the molecules.
This changes the shape of the
protein molecule such that it can't perform its function.
Research is ongoing to
identify which molecules bind with lead.
Some of the proteins known to
be affected by lead regulate blood pressure, (which can cause developmental
delays in children and high blood pressure in adults), heme production (which
can lead to anemia), and sperm production (possibly implicating lead in
infertility).
Lead displaces calcium in the
reactions that transmit electrical impulses in the brain, which is another way
of saying it diminishes your ability to think or recall information.
No Amount of Lead Is Safe
Paracelsus' was a
self-proclaimed alchemist in the 1600s and pioneered the use of minerals
in medical practices.
He believed that all things
have curative and poisonous facets.
Among other things, he
believed lead had curative effects in low doses, but monitoring dosage doesn't
apply to lead.
Many substances are non-toxic or even essential
in trace amounts, yet poisonous in larger quantities.
You need iron to transport
oxygen in your red blood cells, yet too much iron can kill you.
You breathe oxygen, yet again,
too much is lethal.
Lead isn't like those
elements. It's simply poisonous.
Lead exposure of small
children is a main concern because it can cause developmental issues, and kids
engage in activities that increase their exposure to the metal (e.g., putting
things in their mouths, or not washing their hands).
There is no minimum safe
exposure limit, in part because lead accumulates in the body.
There are government
regulations regarding acceptable limits for products and pollution because lead
is useful and necessary, but the reality is, any amount lead is too much.
Anne
Marie Helmenstine, Ph.D.
Chemistry
Expert
Education
Ph.D.,
Biomedical Sciences, University of Tennessee at Knoxville
B.A.,
Physics and Mathematics, Hastings College
Introduction
Ph.D.
in biomedical sciences from the University of Tennessee at Knoxville - Oak
Ridge National Laboratory.
Science
educator with experience teaching chemistry, biology, astronomy, and physics at
the high school, college, and graduate levels.
ThoughtCo
and About Education chemistry expert since 2001.
Widely-published
graphic artist, responsible for printable periodic tables and other
illustrations used in science.
Experience
Anne
Helmenstine, Ph.D. has covered chemistry for ThoughtCo and About Education
since 2001, and other sciences since 2013. She taught chemistry, biology,
astronomy, and physics at the high school, college, and graduate levels. She
has worked as a research scientist and also abstracting and indexing diverse
scientific literature for the Department of Energy.
In
addition to her work as a science writer, Dr. Helmenstine currently serves as a
scientific consultant, specializing in problems requiring an interdisciplinary
approach. Previously, she worked as a research scientist and college professor.
Education
Dr.
Helmenstine holds a Ph.D. in biomedical sciences from the University of
Tennessee at Knoxville and a B.A. in physics and mathematics with a minor in
chemistry from Hastings College. In her doctoral work, Dr. Helmenstine
developed ultra-sensitive chemical detection and medical diagnostic tests.
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and Dotdash
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