Scientists have long known that
children with high levels oftoxic lead
in their bloodstream are more likely
than others to behave impulsively,
have shorter attention spans and
lower lQs and do poorly in school
Research out Tuesday finds that
even children with just moderate levels of lead in their first three years of
life are nearly three times as likely to
be suspended from school by the
time they're 9 or 10 as, those whose
blood-lead levels were much lower.
The study, appearing in the journal
Envirorunental Research, analyzed
medical and school discipline records
of 3,763 children in Milwaukee Public Schools.
The federal Centers for DiSease
Control and Prevention last year told
physicians that there's, essentially no
safe level oflead, but the agency previously said that children with 10 to
20 microgramS oflead per deciliter of
blood had enough of the toxin in
their 'systems to present a "level of
concern." 'Children with 5 or fewer
micrograrils of lead were considered
safe, more or less, because the margin of error in measuring blood-lead
levels put themessentially at zero. '
Researchers, led by Michael Amato of the psychology department of
the University of WISconsin-Madison, studied children whose bloodlead levels were between 10 and 20
micrograms and compared them
with children whose levels were be-
Hans Steiner, a professor' ofpsychiatry at Stanford University and an
,attending physician at Stanford's Lucile Packard Children's Hospital, said
the findings could help schools strugglingwithbehavior problems,including those in Silicon Valley, for whom
he has consulted for years.
''They're fairly sophisticated and
well-funded," Steiner said of schools
in 'California's high-tech corridor,
low 5. Children at the "acute end of "and this would not even occur to
poisoning," with more than 20 mi- them."
crograms, had long been studied, he
In Milwaukee, 'long-standing prosaid, but researchers knewless about grams to, get rid of lead in kids'
those in the moderate range. '
homes have cleaned up the most
Nearly one in three students ex- heavily contaminated sites, but Amaposed to lead had been suspended, to said the city faces a bigger chalcompared withjiIst over one in 10 of lenge cleaning up places that aren't
those not exposed.
so obviously affected.
Lead exposure, the researchers
''There has been quite a lot of imcalculated, explained 23% of the gap provement in Milwaukee over the
in suspension rates between black past 10 years," he said, ''but there is a
and white Milwaukee students.
long way to go."
blood-lead leveis were
between 10 and 20
compar~d them with
children whose levels
~ere below five.