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Children
are not just little adults. Tests on adults--be they laboratory
animals or humans--give few and most likely misguided insights into
the health risks created by pesticide exposure for the fetus and for
children, who are usually far more sensitive to contamination than
adults. |
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Why
are children more sensitive?
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Children are at a stage in their lives when little things can
make a big, life-long difference.
Adults have already passed through development. Their bodies are
fully organized. Their brains have gone through the periods of
most intense growth. Their reproductive systems have matured.
A child is in the midst of this developmental process...a fetus
even more so. The earlier in development, the wider the range
paths that might be followed.
After all, (as one example) it takes intense medical intervention...
surgery and very heavy hormone treatments...to achieve even a
partial sex change in an adult, and the changes are never complete.
But early in embryonic development an embryo can go either way,
male or female. Which road is followed depends first a minute
hormonal trigger at a key moment in the development of the fetus;
a signal that a begins with a chemical message from the embryo's
genes. Without that message, the fetus will develop as a female.
With it, it becomes a male.
Development involves a myriad of choices. Sex is just one. Others
are as basic as the number of fingers and the shapes of the limbs,
or as subtle as intricate patterns in brain wiring and the subsequent
impact on behavior and intelligence. Each one is governed by minute
chemical signals, many of them hormonal. All those decision points
are already passed in an adult; contamination can't affect them.
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Hormonal changes obviously affect adults, too. Changes in testosterone
can cause mood swings; medical doses of estrogen are used to combat
osteoporosis, etc. The levels of hormones involved in these natural
and artificial oscillations, however, are enormous compared to
the levels that are involved in guiding development. Thus, not
only are children and the fetus in the midst of a developmental
miracle, making them vulnerable to events that adults no longer
need to worry about, but the levels of hormones involved in development
vs. those involved in affecting adults are vastly different. This
means that the levels of concern for chemicals interfering with
developmental processes is profoundly lower.
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Children behave in ways that expose them to contaminants with
greater frequency than adults, at least in the home. They crawl
on floors, roll in the grass, stick things in their mouths, chew
and suck on plastic objects.
- The
size of a child relative to that of an adult means that the same
quantity of contaminant ingested by a child will be proportionally
more impactful.
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These
factors all add up to make children more vulnerable than adults. Unfortunately,
however, most of the regulatory science that has been conducted in
the United States (indeed everywhere in the world) has focused on
adults. Adult animals in experiments. Adult humans in studies used
to determine regulatory targets.
Encouraged by concerned scientists and pediatricians, such as Dr.
Philip Landrigan at Mt. Sinai Hospital in NY, the Clinton Administration
in 1997 issued an Executive
Order acknowledging the special sensitivity of children, instructing
each federal agency to make environmental threats to children's health
a high priority and to ensure that all policies, programs, activities,
and standards address disproportionate risks to children that result
from environmental health risks or safety risks.
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In 1996,
Congress passed the Food
Quality Protection Act (FQPA), which contains important provisions
specifically addressing the heightened sensitivity of children:
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- It
requires an explicit determination that tolerances are safe
for children.
- It
includes an additional safety factor of up to ten-fold,
if necessary, to account for uncertainty in data relative
to children.
- And
it requires consideration of children's special sensitivity
and exposure to pesticide chemicals. [The FQPA also addresses
endocrine disruptors directly, through the Endocrine Disruptors
Screening and Testing Advisory Committee (EDSTAC)].
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Unfortunately, implementation
of FQPA has lagged and decisions made by EPA in developing details
of implementation are weakening the intent of the law.
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And perhaps ironically,
industry is using test results from experiments
with adult humans in an effort to demonstrate pesticide safety
and to avoid some of the new requirements established by the 1996
FQPA. Leaving aside for the moment the substantial
ethical questions this practice raises, the simple fact is that
tests on adults will not demonstrate safety for kids. The tests,
therefore, are worthless, which makes the ethical issues that much
more acute. |
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