=======================Electronic Edition========================
RACHEL’S HAZARDOUS WASTE NEWS #376
—February 10, 1994—
News and resources for environmental justice.
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HOW RISK ASSESSMENT POISONED OUR CHILDREN
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 children.”
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 Council. [2, pg.18]
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 environment.” [2, pg.18]
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 discharge.
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, Ph.D.
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[1] Committee on Environmental Health, American Academy of
Pediatrics, “Lead Poisoning: From Screening to Primary
Prevention,” PEDIATRICS Vol. 92 (July 1993), pgs. 176-183.
Descriptor terms: children; lead; pb; paint; australia; national
research council; american academy of pediatrics; iq; brain
damage; housing; gasoline; soil; dust; central nervous system;
kidney; blood;