=======================Electronic Edition========================
RACHEL’S HAZARDOUS WASTE NEWS #25
—May 18, 1987—
News and resources for environmental justice.
——
Environmental Research Foundation
P.O. Box 5036, Annapolis, MD 21403
Fax (410) 263-8944; Internet: erf@igc.apc.org
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CHILD DEVELOPMENT RETARDED BY EARLY EXPOSURE TO TOXIC LEAD, EVEN AMONG
WELL-TO-DO FAMILIES.
Exposure to very small amounts of lead before birth retards a child’s mental and physical development
during the first two years of life, and perhaps longer, researchers reported April 23 in the NEW ENGLAND
JOURNAL OF MEDICINE. Even exposure to amounts of lead considered safe for children caused lower
scores on tests of problem-solving, perception, memory, learning and coordination.
The Boston researchers studied 249 infants over a two-year period, dividing them into three groups
according to their exposure to the metallic poison, lead. Lead exposure was judged from blood samples
taken from umbilical cords at birth. The lowest group had less than 3 micrograms of lead per deciliter of
blood (ug/dl); the next group had 3 to 10 ug/dl; and the high exposure group had 10 to 25 ug/dl. Twenty-five
ug/dl is the threshold above which lead is considered unacceptably high in a child, according to criteria set
by the federal Centers for Disease Control in Atlanta, GA.
Children in the low-lead exposure group consistently performed better on a series of tests aimed at
measuring their overall mental and physical development, compared to the high lead exposure group.
All 249 of the children came from socially advantaged families. Thus, researchers wonder if their results
don’t underestimate the problem because, in an impoverished environment, the effects of lead might be
amplified by factors such as poor nutrition.
The researchers point out that other studies of umbilical cord blood reveal that about 25% of all urban
newborns have more than 10 ug/dl lead in their blood.
–Peter Montague, Ph.D.
Descriptor terms: developmental disorders; lead; children; new england journal of medicine; studies; cns;
central nervous system; statistics;