Special Problems of Pesticide Exposure for
Children
excerpted from Failing Health, Pesticide
Use in California Schools, by the California
Public Interest Research Group Charitable
Trust
Children are Less Tolerant
to Toxic Chemicals
Children are not simply little adults. Early
developmental stages of their organs, nervous
systems, and immune systems, greater rates
of cell division, and their lower body weight
increase their susceptibility to pesticide
exposure. Immature organs and other developing
biological systems are particularly vulnerable
to toxic contaminants. Furthermore, pesticides
may become more concentrated in the fatty
tissues of young children because their fat
as a percentage of total body weight is lower
than for adults.
A 1993 report by the National Research Council
of the National Academy of Sciences has shown
that children are more susceptible than adults
to the health effects from low-level exposures
to pesticides over the long-term .Animal studies
also suggest that the young are more susceptible
to the effects of toxic chemicals. A review
of 269 drugs and toxic substances, including
a number of pesticides, found that the lethal
dose was lower in newborn rodents than in
adult rodents in 86% of the cases.
Children Receive Relatively
Greater Exposure
In addition to being more vulnerable to pesticide
toxicity, children’s behavior and physiology
make them more likely to receive greater pesticide
exposures, relative to adults. For example,
significant exposure to pesticides occurs
through the skin – the largest organ in the
human body – and children have much more skin
surface for their size than adults.Similarly,
children have a higher respiratory rate, enabling
them to inhale airborne pesticides at a rate
faster than adults.Children’s increased contact
with floors, lawns and playgrounds also increases
exposure. Very young children who put fingers
and other objects in their mouths may face
even greater exposure. Finally, the breathing
zone for children is usually closer to the
floor where pesticides are re-suspended into
the air after floor surfaces are disturbed.
Children are Exposed to
Pesticide Residues in Dust and Carpets
Although pesticides contaminate air, soil,
food, water and surfaces, studies designed
to examine children’s exposure to pesticides
indicate that the largest number of chemicals
and the highest concentrations are often found
in household dust.
Carpets act as long-term reservoirs for pesticides
that are sprayed indoors.A study assessing
pesticide exposure from carpet dust in homes
found that the average number of pesticides
found in the carpet dust samples was 12, compared
to 7.5 in air samples collected in the same
residences. Moreover, in all residences sampled,
13 pesticides were found in carpet dust that
were not detected in the air. Diazinon, a
neurotoxic insecticide, was detected in nine
of 11 carpets tested.Exposure may be further
exacerbated when carpets are cleaned, allowing
pesticides to become airborne again and available
for inhalation.
Not all of the residues in dust stem from
the indoor use of pesticides. One study showed
residues of 2,4-D and dicamba can be tracked
in from outside on shoes. Even areas which
were not treated, including lawn area and
carpets, showed levels of 2,4-D after the
spraying – most likely the result of spray
drift during application. Researchers estimated
that residues of 2,4-D can persist in household
carpet dust for as long as one year.
Children are Exposed to
Pesticides through Ventilation Systems
A building’s ventilation system may also
contribute to greater pesticide exposure.
Some pesticides can become airborne and spread
throughout heat and air conditioning systems,
potentially causing a repeating source of
exposure.
In 1994, the insecticide propoxur was evidently
distributed through a California school via
the building’s air conditioning system. A
teacher’s aide entered the building immediately
after application and became ill with nausea,
headache, nose and eye irritation and breathing
difficulty.
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