Experts Demand More Study of Childhood Exposure to Toxins

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Experts Demand More Study of Childhood Exposure to Toxins

May 25, 1999

By Mann

NEW YORK -- Childhood exposure to lead, pesticides and other environmental

toxins may play a role in causing attention deficit/hyperactivity disorder

(ADHD), aggression, delinquency and certain learning disabilities, leading

child health experts said here Monday.

``Neurodevelopmental disorders are very common among children born in this

country. About 3 percent of all Americans suffer from some type of

neurodevelopmental disorder,'' said Dr. Philip Landrigan, professor of

pediatrics at Mount Sinai School of Medicine in New York and the director of

the newly established Center for Children's Health and the Environment at

Mount Sinai. ``Yet three-quarters of neurodevelopmental disorders have no

known cause,'' he added, speaking at a conference on the effects of

environmental toxins on children's brains and nervous-system disorders.

The deleterious effects of certain toxins that persist in the environment

may be more harmful to growing children, panelists at the conference said,

because children eat more food and drink more water pound per pound than

adults, and their brains and nervous systems are still developing.

They are also ``closer to the ground,'' meaning that they have a 10 times

greater exposure to dust than adults, said Bernard Weiss, professor of

environmental medicine and pediatrics at the University of Rochester School

of Medicine and Dentistry.

Studies have linked lead exposure; polychlorinated biphenyls (PCBs), a group

of chemicals formerly used to manufacture plastics, insulation materials and

fire retardants; and certain pesticides including chlorphylobos, the most

commonly used pesticide in New York, to a plethora of neurodevelopmental

disorders including ADHD. Children with this disorder may have reduced

attention spans, are easily distracted and tend to engage in impulsive

behavior.

Exactly how toxins might cause these disorders is not fully understood, the

experts said, but they were unanimous in their push for more research into

the matter.

Landrigan pointed out that ``every day, children are exposed to a whole

suite of chemicals that have never been tested.''

Preliminary study results presented here Monday showed that bone-lead levels

are much higher among delinquents than non-delinquents, said Dr. Herbert L.

Needleman, professor of child psychiatry and pediatrics at the University of

Pittsburgh School of Medicine.

Although efforts have been made to reduce lead exposure by removing the

metal from gasoline, lead paint in older houses and lead in drinking water

are still common sources of exposure, experts pointed out.

``Lowering population lead exposure is having and is going to continue to

have beneficial effects,'' Landrigan said. He added that while

lead-reduction measures could influence reductions in crime rates in certain

communities, other factors are likely to play a role as well.

An 11-year study assessing the effects of PCBs on developing infants showed

that children whose mothers reported eating two to three servings of fish

from Lake Michigan each month during their pregnancies were more likely to

have poor short-term memory and attention spans than children whose mothers

did not eat fish from lake. The lake is known to contain PCB-contaminated

fish.

PCBs were banned in most nations in the 1970s, but they persist in the

environment for a long time, explained study author ph L. sen,

professor of psychology at Wayne State University in Detroit.

The conference was sponsored by the National Institute of Environmental

Health Sciences, the Pew Charitable Trusts and the Institute for Health and

Environment at the University of Albany School of Public Health.