Lead levels believed safe found harmful

Study shows drop in intellectual development

April 17, 2003|By Thomas H. Maugh II | Thomas H. Maugh II,SPECIAL TO THE SUN

Lead levels now widely believed to be safe in children actually produce a severe impact on intellectual development, researchers report.

Blood levels of lead below current federal and international guidelines of 10 micrograms per deciliter produce a surprisingly large 7.4-point drop in IQ, a U.S. team reports in today's New England Journal of Medicine. Researchers estimate that 1 in 50 U.S. children has lead levels above that guideline and that 1 in 10 has levels of 5 micrograms/deciliter or above - well within the dangerous range.

"People have been asking, `How low [a lead concentration] is low enough?'" said Dr. Richard Canfield of Cornell University, one of the leaders of the study. "The fact is, in our study, we found no evidence for a safe level. There is no safe level of exposure."

The findings "reflect the growing opinion that low levels of lead are more toxic than we thought," said Dr. Herbert A. Needleman, a prominent lead researcher who was not involved in this study. "When we took the lead out of gasoline that left one remaining big source, old houses. Now we have to take the lead out of old houses."

An estimated 38 million houses built before 1950 still have lead-based paints on their walls.

Just as parents should protect their children from the effects of smoking and alcohol use, they "should be aware of sources of lead in their environment and, most importantly, should try to engage in some type of cleanup or abatement so the child never comes in contact with lead."

In a separate paper in the journal, researchers from the Environmental Protection Agency also found that low levels of lead delay puberty for several months in young girls.

Thomas H. Maugh II writes for the Los Angeles Times, a Tribune Publishing newspaper.

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