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FRIGHTENING DATA: PESTICIDES AND CHILDREN'S BRAINS
Learning disabilities, while common in the general
population, are almost epidemic among delinquents and criminals.
Up to three-fourths of delinquents have learning disabilities,
and up to a third of teenagers with learning disabilities will be
arrested within five years after leaving school.
That's why new research by Elizabeth Guillette and
colleagues is intriguing researchers interested in the roots of
criminality. Guillette et al., studying Yaqui Indians in Northern
Mexico, report a stunning link between pesticide exposure (at
levels possibly comparable to agricultural areas in the U.S.) and
motor and mental problems similar to those seen in children with
learning disabilities.
The researchers studied Yaqui four- and five-year-olds
living in two different regions: lowland agricultural areas, in
which fields are sprayed up to 45 times per crop and two crops
are grown per year; and foothills, where virtually no pesticides
are used. The Yaquis were selected, the researchers say, to
eliminate many possible confounding factors. The two groups of
study subjects are genetically and culturally similar, and have
similar diets and standards of living.
The researchers evaluated 33 children from high-pesticide
agricultural areas, and 17 control subjects from the foothills.
They report that "the exposed children demonstrated decreases in
stamina, gross and fine eye-hand coordination, 30-minute memory,
and the ability to draw a person." Differences in drawing ability
were particularly startling: four-year-olds from the foothills,
for instance, were able to draw stick figures with correct
features, while pesticide-exposed four-year-olds drew meaningless
scribbles. This suggests, the researchers say, "a breakdown
between visual sensory input and neuromuscular output, as found
with brain dysfunction."
Similarly, Guillette et al. say, the pesticide-exposed
children's poor hand-eye coordination could indicate brain
dysfunction. In addition, the researchers say, "The inability to
remember a meaningful statement after 30 minutes has implications
for school performance and performance in social activity."
Although the researchers did not specifically study
behavior, they note that foothills children often played in
groups, participating in games, pretend parties for dolls, and
similar activities. The valley children, on the other hand,
"appeared less creative in their play; they roamed the area
aimlessly or swam in irrigation canals with minimal group
interaction."
Equally striking was the difference in aggressive behavior:
the valley children hit their siblings, and became aggressive
when corrected by their parents. "These aggressive behaviors,"
Guillette et al. say, "were not noted in the foothills." In a
personal communication, Guillette noted, "Overall, disruptive
behavior was the norm with exposed children."
Neurotoxicologist David Carpenter, commenting on the study
in a Science News article, said, "I know of no other study that
has looked at neurobehavioral impacts-cognition, memory, motor
ability-in children exposed to pesticides." He notes that the
study's implications are "horrendous," because the level of
impairment shown in the pesticide-exposed children "is
incredible-and may prove irreversible."
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"An anthropological approach to the evaluation of preschool
children exposed to pesticides in Mexico," Elizabeth A.
Guillette, Maria Mercedes Meza, Maria Guadalupe Aquilar, Alma
Delia Soto, and Idalia Enedina Garcia, Environmental Health
Perspectives, Vol. 106, No. 6, June 1998, pp. 347-353. Address:
E. A. Guillette, 32 SW 43rd Terrace, Gainesville, FL 32607.
--and--
"Picturing pesticides' impacts on kids," J. Raloff, Science
News, Vol. 153, June 6, 1998.
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