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#213 - Lead -- Part 1: A Hopeful New Year's Resolution For A Nation That Has Poisoned Its Children, 25-Dec-1990

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

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.

Get: NEHANES 2: "Blood Lead Levels for Persons Ages 6 Months- 74 Years,
United States, 1976-80.... Data From the National Health and Nutrition
Examination Survey." VITAL AND HEALTH STATISTICS Series 11, No. 233
[DHHS Publication No. (PHS) 84- 1683; U.S. Department of Health and
Human Services, Public Health Service, National Center for Health
Statistics, Hyattsville, MD], August, 1984. Available from your local
library via interlibrary loan from any federal depository library;
every state has at least one federal depository library.

ATSDR 1: Agency for Toxic Substances and Disease Registry, THE NATURE
TO CONGRESS (Atlanta, GA: Agency for Toxic Sub- stances and Disease
Registry, Public Health Service, U.S. Department of Health and Human
Services [1600 Clifton Rd. - Mail Stop E-33, Atlanta, GA 30333; phone
(404) 639-0730], July, 1988). A thick volume, free upon request.

ATSDR 2: Agency for Toxic Substances and Disease Registry,
TOXICOLOGICAL PROFILE FOR LEAD (Springfield, VA: National Technical
Information Service [NTIS, 5285 Port Royal Rd., Springfield, VA 22161;
phone (703) 487-4650], June, 1990); request document PB 90-267378;
$21.95 plus 3.00 shipping.

--Peter Montague


Descriptor terms: heavy metals; lead; children; health effects;
national health and nutrition examination surveys; studies; mental
illnesses; atsdr; developmental disorders;