excerpts from various sources
Lead poisoning: From Wikipedia, the free encyclopedia
“Lead
poisoning (also known as plumbism, colica pictorum, saturnism, Devon
colic, or painter's colic) is a type of metal poisoning and a medical
condition in humans and other vertebrates caused by increased levels of
the heavy metal lead in the body.
Lead interferes with a variety of body
processes and is toxic to many organs and tissues including
the heart, bones, intestines, kidneys,
andreproductive and nervous systems. “...
“It
interferes with the development of the nervous system and is therefore
particularly toxic to children, causing potentially
permanent learning and behavior disorders. Symptoms include abdominal
pain, confusion, headache, anemia, irritability, and in severe
cases seizures, coma, and death.”
“Routes of
exposure to lead include contaminated air, water, soil, food, and
consumer products. Occupational exposure is a common cause of lead
poisoning in adults. According to estimates made by the National
Institute of Occupational Safety and Health (NIOSH), more than 3 million
workers in the United States are potentially exposed to lead in the
workplace.”
...
Neurons“Lead
exposure damages cells in the hippocampus, a part of the brain involved
in memory. Hippocampi of lead-exposed rats (bottom) show structural
damage such as irregular nuclei (IN) and denaturation of myelin(DNS)
compared to controls (top).”
...
“Lead
interferes with the release of neurotransmitters, chemicals used
byneurons to send signals to other cells. It interferes with the release
ofglutamate, a neurotransmitter important in many functions including
learning, by blocking NMDA receptors. “
...
“The
targeting of NMDA receptors is thought to be one of the main causes for
lead's toxicity to neurons. A Johns Hopkins University report found
that in addition to inhibiting the NMDA receptor, lead exposure
decreased the amount of the gene for the receptor in part of the
brain. In addition, lead has been found in animal studies to
cause programmed cell death in brain cells.”
...
Reversibility“Outcome
is related to the extent and duration of lead exposure. Effects of lead
on the physiology of the kidneys and blood are generally reversible;
its effects on the central nervous system are not. While peripheral
effects in adults often go away when lead exposure ceases, evidence
suggests that most of lead's effects on a child's central nervous system
are irreversible.Children with lead poisoning may thus have adverse
health, cognitive, and behavioral effects that follow them into
adulthood.”
...
Encephalopathy“Lead
encephalopathy is a medical emergency and causes permanent brain damage
in 70–80% of children affected by it, even those that receive the best
treatment.” The mortality rate for people who develop cerebral
involvement is about 25%, and of those who survive who had lead
encephalopathy symptoms by the time chelation therapy was begun, about
40% have permanent neurological problems such as cerebral palsy.”
Long-term“Exposure
to lead may also decrease lifespan and have health effects in the long
term. Death rates from a variety of causes have been found to be higher
in people with elevated blood lead levels; these include cancer, stroke,
and heart disease, and general death rates from all causes. Lead is
considered a possible human carcinogen based on evidence from animal
studies. Evidence also suggests that age-related mental decline and
psychiatric symptoms are correlated with lead exposure. Cumulative
exposure over a prolonged period may have a more important effect on
some aspects of health than recent exposure. Some health effects, such
as high blood pressure, are only significant risks when lead exposure is
prolonged (over about one year).”
...
“With
the Industrial Revolution in the 19th century, lead poisoning became
common in the work setting. The introduction of lead paint for
residential use in the 19th century increased childhood exposure to
lead; for millennia before this, most lead exposure had
been occupational. An important step in the understanding of childhood
lead poisoning occurred when toxicity in children from lead paint was
recognized in Australia in 1897.
“France, Belgium,
and Austria banned white lead interior paints in 1909; the League of
Nations followed suit in 1922. However, in the United States, laws
banning lead house paint were not passed until 1971, and it was phased
out and not fully banned until 1978.”
...