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#376 - How Risk Assessment Poisoned Our Children, 09-Feb-1994

According to the American Academy of Pediatrics, somewhere between 2
and 4 million American children have sufficient lead in their blood to
diminish their IQ, reduce their physical stature, damage their hearing,
decrease their hand-eye coordination and impair their ability to pay
attention in school. This damage is thought to be permanent.[1] Lead is
a soft, gray toxic metal that has been mined from the earth and formed
into useful items for 5000 years. Its toxicity to miners and workers
was well established among ancient Greeks and Romans long before the
birth of Christ.

The specific toxicity of lead to children was first described in a
medical journal in 1897, and a key source of lead poisoning in children
-- paint flaking off a porch railing -- was identified and described in
a medical journal in 1904. The U.S. National Research Council recently
pointed out that, in 1897, the toxic paint problem was sufficiently
well-understood for at least one manufacturer of paint in New York City
to advertise, "Aspinall's Enamel is NOT made with lead and is non
poisonous."[2,pg.25] In 1920, to prevent the poisoning of its children,
Australia passed a law curbing lead in paint. The U.S. delayed 50 years
before taking similar action in 1970.

As a result of that delay, a physician writing in the AMERICAN JOURNAL
OF PUBLIC HEALTH in 1992 would say flatly, "Lead poisoning is epidemic
among American children."[3] The American Academy of Pediatrics in 1993
began its official statement on childhood lead poisoning by quoting the
federal Department of Health and Human Services saying lead poisoning
is "the most important environmental health problem facing young

The Academy then recounted the history of lead regulation, illustrating
how millions of American children were poisoned. Reading between the
lines of the Academy's sad tale, we can gather that the medical and
public health communities buckled under industry pressure and abandoned
their own most fundamental principle, DISEASE PREVENTION. The Academy
said flatly in 1993, "Childhood lead poisoning is preventable." Then
why hasn't it been prevented? It's a fair question.

For the last 30 years, instead of asking how to prevent lead poisoning,
the medical community has taken a risk assessment approach, asking,
"How much lead is safe for industry to put into children?" In 1960, the
medical community answered the question by saying it was safe for a
child to have 60 micrograms of lead in each deciliter [10th of a liter]
of blood (or 60 mcg/dL). That answer turned out to be wrong, and in
1975 the medical community answered the question by saying 30 mcg/dL
was safe. That, too, turned out to be wrong, and in 1985 they set 25
mcg/dL as the safe level. That, too, turned out to be wrong, and in
1991 the medical community said 10 mcg/dL was safe. As we shall see,
the National Research Council now believes that even this "safe" level
may not be safe.

But first let's review what happens to children with more than 10
mcg/dL lead in their blood. The American Academy of Pediatrics recently
reviewed 18 scientific studies showing that lead diminishes a child's
mental abilities. "The relationship between lead levels and IQ deficits
was found to be remarkably consistent," the Academy said. "A number of
studies have found that for every 10 mcg/dL increase in blood lead
levels, there was a lowering of mean [average] IQ in children by 4 to 7
points." This may not sound like a major loss, but an average IQ loss
of 5 points puts 50% more children into the IQ 80 category, which is
borderline for normal intelligence. It also reduces the number of high
IQs; for example, one small group that should have contained 5 children
with IQs of 125, contained none.[1]

The American Academy of Pediatrics says such losses are permanent and
they translate into reduced educational attainment, diminished job
prospects, and reduced earning power. Two groups of children in first
and second grade --one with 25 mcg/dL and the other with 35 mcg/dL --
were studied into adulthood. The high-lead group was seven times as
likely not to graduate from high school and six times as likely to have
reading scores two grades below expected, after adjusting for a number
of factors, including socioeconomic status and parental IQ. The high-
lead children also had higher absenteeism in their final year of
school, lower class rank, poorer vocabulary and grammatical reasoning
scores, longer reaction times, and poorer hand-eye coordination.

Because the U.S. has banned lead in gasoline, and banned lead solder in
tin cans, average [mean] blood lead in U.S. children has diminished
from 16 down to about 5 mcg/dL during the last 15 years. However, as
the American Academy of Pediatrics says, "there are still many children
at high risk of exposure."

Forty-two million families live in housing that contains an estimated 3
million tons of lead in paint, equivalent to about 140 pounds of lead
per household, or 63 billion micrograms of lead in each household. As
that paint slowly disintegrates into house dust, if a child gets lead
onto its hands and into its mouth at the rate of just 150 micrograms
per day, the child is poisoned, according to the National Research

In addition to paint, house dust also contains lead tracked into homes
from soil outside. Between 1920 and 1980, the oil and automobile
companies aggressively defended and protected their right to spew toxic
lead into every neighborhood in America; they left a legacy of 30
million tons of lead in soils before the nation came to its senses and
put a muzzle on these industries.

But the damage was already done, and the poisoning now continues
everywhere. A study in the early 1980s showed that, among white
children, 7% in higher socioeconomic status areas and 25% in poorer
communities had blood lead levels greater than 15 mcg/dL. Among black
children in poor communities, this prevalence was 55%.[1]

The lead problem was inevitable, given the decision to allow lead in
paint, gasoline, and other products. The National Research Council in
its 1993 book on the lead problem, summarized the situation starkly:
"Once lead is mined and introduced into the environment, it persists.
Over time, lead in various forms becomes available to the body as small
particles. Most of the 300 million metric tons of lead ever produced
remains in the environment, largely in soil and dust. That explains, in
part, why background concentrations of lead in modern North Americans
are higher by a factor of 100 to 1000 than they were in pre-Columbia
Americans. Today's production evolves into tomorrow's background
exposure, and despite reductions in the use of lead for gasoline,
overall lead production continues to grow and federal agencies have not
addressed the impact of future increases of lead in the

In sum, if you mine lead out of the ground, it will eventually spread
into the environment. It will get into soil, then into food and water.
Eventually it will get into humans (not to mention wildlife), where it
will take its toll on health. This is inevitable. The only way to avoid
this outcome, is to stop mining lead out of the deep earth. Zero

The National Research Council says modern humans are estimated to have
total body burdens of lead approximately 300-500 times those of our
prehistoric ancestors.... [2,pg.xii] According to careful measurements
of human bones, pre-Columbian inhabitants of North America had average
blood lead levels of 0.016 mcg/dL -- some 625 times lower than the 10
mcg/dL now established as "safe" for our children.[4] On the face of
it, it seems unlikely that levels of a potent nerve poison 625 times
natural background can be "safe" in children.

The National Research Council admits as much: "There is growing
evidence that even very small exposures to lead can produce subtle
effects in humans. Therefore, there is the possibility that future
guidelines may drop below 10 mcg/dL as the mechanisms of lead toxicity
become better understood."[2,pg.3]

Despite 80 years of research, the toxicity of lead in children is still
not fully understood. According to the Council, "Childhood lead
poisoning involves injury in at least 3 organ systems: the central
nervous system (specifically, the brain), the kidney, and the blood-
forming organs. Other systems are also affected, but the nature of
their toxic injury has not been as well characterized."[2,pg.32] In
other words, we know additional damage (beyond the 3 organ systems) is
occurring, but we don't understand it.

Furthermore, the Council says, "[O]nce lead is absorbed from a specific
source, it is added to a body burden that contributes to various health
effects. Therefore, exposures small enough to have been viewed as of
little importance are now taken more seriously. In other words, we must
consider the aggregate impact of multiple small lead sources in
assessing health risk."[2,pg.99]

As these quotations reveal, the National Research Council is still
operating in the old, scientifically bankrupt "risk assessment" mode of
thinking -- trying to establish some "safe" level of poison that
industry will then be allowed to put into children. For this mode of
thinking to protect children, all forms of damage must be understood
thoroughly, which they can't be. The effects of all sources of lead
exposure must be understood, which they can't be. The cumulative
impacts of lead, malnutrition, and many other stresses on a child
(PCBs, pesticides, and so forth) must all be factored in to establish
cumulative "safe" levels. Science has no way to calculate the
cumulative effects of multiple exposures.

This bankrupt, unscientific mode of thinking -- risk assessment -- is
guaranteed to allow the poisoning to continue at some level. A truly
preventive approach asks not, "How much lead is safe?" but instead
asks, "What are the alternatives for each use of lead? How can we avoid
lead entirely?" Given the Clinton administration's recent wholesale
commitment to risk assessment as the basis for all federal regulations
[RHWN #359], we must also ask, are so many of us now brain-damaged by
lead and other toxins that we are no longer able, as a society, to
frame the right questions?

--Peter Montague


[1] Committee on Environmental Health, American Academy of Pediatrics,
"Lead Poisoning: From Screening to Primary Prevention," PEDIATRICS Vol.
92 (July 1993), pgs. 176-183.

[2] National Research Council, MEASURING LEAD EXPOSURE IN INFANTS,
Academy Press, 1993).

[3] Philip J. Landrigan, "Commentary: Environmental Disease --A
Preventable Epidemic," AMERICAN JOURNAL OF PUBLIC HEALTH Vol. 82 (July
1992), pgs. 941-943.

[4] A. Russell Flegal and Donald R. Smith, "Lead Levels in
Preindustrial Humans," NEW ENGLAND JOURNAL OF MEDICINE Vol. 326 (May 7,
1992), pgs. 1293-1294.

Descriptor terms: children; lead; paint; australia; national research
council; american academy of pediatrics; iq; brain damage; housing;
gasoline; soil; dust; central nervous system; kidney disease; blood;