=======================Electronic Edition========================
RACHEL’S HAZARDOUS WASTE NEWS #213
—December 26, 1990—
News and resources for environmental justice.
——
Environmental Research Foundation
P.O. Box 5036, Annapolis, MD 21403
Fax (410) 263-8944; Internet: erf@igc.apc.org
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A HOPEFUL NEW YEAR’S RESOLUTION FOR A
NATION THAT HAS POISONED ITS CHILDREN.
The exposure of American children to damaging quantities of the
toxic metal, lead, has reached terrible epidemic proportions. An
examination of this scourge may give us insight into other
environmental problems.
Our facts are taken from three government studies. One we’ll call
NEHANES 2 (short for Second National Health and Nutrition
Examination Survey); the others we’ll call ATSDR 1 and ATSDR 2
(short for two studies published by the Agency for Toxic
Substances and Disease Registry–a federal agency). Full
citations to all three studies appear in our last paragraph,
below.
Lead is a naturally-occurring element, a soft, bluish-gray metal
that occurs in the ground and is naturally toxic. At some
locations, lead occurs in such high concentrations that it can be
readily mined. Because it occurs naturally, it is found
everywhere in low levels–in rocks, in soil, in plants, in
animals, and in humans. Before lead came into industrial use,
human blood contained approximately 0.5 micrograms of lead in
each tenth of a liter [deciliter] of blood (expressed in
scientific shorthand as 0.5 micrograms per deciliter). A
microgram is a millionth of a gram and there are 28 grams in an
ounce; a liter is about a quart; a deciliter is a tenth of a
liter, or about half a cup. Therefore we say that the “natural
background level” of lead in human blood is 0.5 micrograms per
deciliter (ATSDR 1, pg. 16). Whenever such data are available, a
natural background level is a good benchmark against which to
measure the size of a problem. As a rule of thumb, a 10% increase
above background should raise eyebrows and questions; a doubling
of a background level is significant; a tenfold increase above
background is very large.
According to the best available data (NEHANES 2, pg. 26), the
average (mean) concentration of lead in the blood of American
children ages 6 months to 5 years is 16 micrograms per deciliter;
thus American children have 30 times as much lead in their blood
as humans have naturally. A 30-fold increase above background is
a very large increase indeed; we should expect to see adverse
effects from such a rise. When do effects start to occur?
As with any characteristic (such as height or weight), blood in
lead varies from individual to individual. When the average is
16, some children have 3 micrograms per deciliter and some have
30 or more. An important medical question is: at what point do
adverse effects become observable?
The answer, for the human fetus exposed while in the womb, is:
reductions in gestational age (length of pregnancy), birth
weight, birth height, girth of chest, and circumference of head
are observable in children who have 10 micrograms per deciliter
and in some cases even less (ATSDR 1, pgs. IV-17 through IV-19;
ATSDR 2 pg. 23). For these growth-related effects, there is no
observable “threshold”–no amount of lead below which there are
no observable effects. This indicates that the only “safe” amount
of lead in blood is natural background. (Even natural background
may not be entirely safe, but it’s surely the best we could
expect to achieve as an average.)
At 10 micrograms per deciliter and even lower levels of lead in
blood, other adverse medical effects are observable in American
children under 5 years old: cognitive ability (as measured on
standard tests, including the Stanford Binet IQ test) is impaired
at blood-levels below 10 micrograms per deciliter. And children’s
hearing is impaired by blood-lead levels below 10 micrograms per
deciliter; it is worth pointing out that hearing impairment can
make learning disabilities worse. (ATSDR 2, pg. 21)
Children ages 6 to 24 months with blood-lead of 10 micrograms per
deciliter and higher score 4.8 points lower (out of 100),
measured on a standardized test called Bayley Mental Development
Index (MDI), compared to children with 3 micrograms per deciliter
or less. (ATSDR 1, pgs. IV-7 through IV-19; ATSDR 2, pg. 24.)
There is now considerable evidence that such retardation in
normal physical and mental development is not reversed as time
passes. The effects are evidently irreversible. (ATSDR 1, pg.
IV-11.)
Thus there seems to be little doubt that lead in children’s blood
at 10 micrograms per deciliter or even less retards physical,
mental, and perhaps emotional development; these effects are
permanent.
How many American children have blood lead levels of 10
micrograms per deciliter or higher? Answer: an astonishing 88%.
(NEHANES 2, Table 4, pg. 26, shows that among American children 5
years old or younger, 63.3% have between 10 and 19 micrograms per
deciliter; 20.5% have 20 to 29 micrograms per deciliter; 3.5%
have 30 to 39 micrograms per deciliter; and 0.5% have 40 or
more.) We have poisoned our children.
It is therefore proper to ask what happens to a nation that
poisons its children? The federal Agency for Toxic Substances and
Disease Registry (ATSDR) has asked and answered this question:
“Lead-induced reductions in IQ, for instance, not only place the
individual at a disadvantage, but also eventually place the
nation at a collective disadvantage in an increasingly
competitive, technical, and cognitionintensive world economy.”
(ATSDR 1, pg. IV-1.)
What can be done? ATSDR says, “At the same time that progress is
being made to reduce some sources of lead toxicity, scientific
determinations of what constitute ‘safe’ levels of lead exposure
are concurrently declining even further. Thus increasing
percentages of young children and pregnant women fall into the
‘at-risk’ category as permissible exposure limits are revised
downward. Accompanying these increases is the growing dilemma of
how to deal effectively with such a widespread public health
problem. Since hospitalization and medical treatment of
individuals with blood-lead levels below approximately 25
micrograms per deciliter is neither appropriate nor even
feasible, the only available option is to eliminate or reduce the
lead in the environment.” (ATSDR 1, pgs. 16-17)
It is clear that removing lead from the American environment
should be a matter of highest priority. Our national security
depends upon it more than it depends upon military buildups or
showdowns. Furthermore we must have a policy of zero discharge.
ATSDR points out that the easy steps have already been taken to
reduce lead in the environment. Lead has been restricted in
paint, and in gasoline. Lead in food and in drinking water has
already been subjected to regulation (though not yet to effective
enforcement). “Lead in old paint, dust, and soil, however, is
pervasive and dispersed, and fundamentally different approaches
to abatement will be needed. If the Nation is to solve these
difficult facets of the lead problem, society must make a strong
effort to do so.” (ATSDR 1, pg. 17, emphasis added.)
But the nation cannot make a strong effort without a coordinated
plan–and that requires leadership. It is long past time for the
environmental community to press George Bush, our self-proclaimed
“education” and “environmentalist” President, to force him to
acknowledge that the poisoning of our children is a national
scandal, an intolerable disgrace. Then we must force him to act
to make America once again safe for its children. Let us resolve
to work together in ’91 to make real change happen.
–Peter Montague, Ph.D.
Descriptor terms: heavy metals; lead; children; health effects;
national health and nutrition survey; studies; mental illnesses;
atsdr; developmental disorders;