Amounts of lead well below those previously considered hazardous can adversely affect the intelligence and school behavior of young children, according to a study published in today's edition of the New England Journal of Medicine.
The study, which involved 3,329 children in the Boston area, has serious implications for childern in the District of Columbia and other urban areas, local officials said yesterday.
In 1977, 15 percent of the children screened in Wasington for lead poisoning had lead levels in their bodies equal to or above those of the children in the study's "high lead" group.
The study, by Dr. Herbert Needleman of Havard University Medical School and Boston Children's Hospital, compared the IQs of 58 "high lead" levels. The study also imcludes analyses by teachers of the learning abilities and behavior of the children.
All children in the study were first and second-grade students in Chelsea and Somerville, Mass., outside Boston.
According to the study, the "high-lead" group had a mean IQ of 102.1, compared to the "low lead" group's mean of 106.6.
The teachers perceived even more dramatic differences in the behaviors of the two groups, with 26 percent of the "high lead" group rated as unable to follow a sequence of directions, while only 8 percent of the "low-lead" children were in that category.
The Needleman study also found that the children in the "high lead" group were much more commonly rated by their teachers as being disorganized, distractable, hyperactive, implusive, easily frustrated, dependent, not persistent and having low over-all functional ability.
The needleman study is "a little alarming and that's an understatement," said Ron Thomas, who is in charge of the lead screening program for the District's Department of Human Resources.
"You couple that with the fact that 85 of 135 schools in the District have lead in them and nothing's been done," and it's a major problem, Thomas said.
District officials have known since 1976 that the 85 schools had lead paint on some of their walls and ceilings. But money earmarked for removing the old paint has been cut out of the city budget in a least two fiscal years, officials of the city's General Services Department said.
Although some specialists consider the lead paint in the schools a hazard. Dr. Bailus Walker, director of environmental health for the city, said the paint constitutes a hazard in only five schools in which the paint in peeing from the walls and ceilings.
Most researchers agree that old lead paint is a major health hazard. Many others, however, are coming to believe that there is an aqual hazard posed by lead in dust outdoors, which is generally believed to come from leaded gasoline. The federal Department of Energy is considering relazing restrictions on the use of leaded gas, and has come under attack from environmentalists for doing so.
According to Stephanie Karsten, co-ordinator of the Committee of L.E.A.D., based at Children's Hospital National Medical Center here, the Boston study "has a lot of very serious implications for the direction we take here.
"My overall first thought is this points to the need for the genral public to be concerned about lead," Karsten said. "People haven't been concerned because they've thought it was just a problem of the most powerless segments of society who were at risk."
The children in the study had lead levels well below those at wich physical symptoms, or classic lead poisoning, appear.
Lead poisoning, which is all that most persons think of when discussing lead and children, is generally thought to be a disease of the inner city, of black children living in deteriorating housing.
However, Karsten said, 40 percent of the children screened at Children's Hospital and found to have elevated levels of lead in their blood last year came from homes where there was no lead hazard.
Ninety-eight percent of Needleman's "high lead" group and 97 percent of his "low lead" group were white. "I didn't want use race as a confounding variable," Needleman said, "I believe lead is not just a problem of the black race."
The Needleman study differs in several important respects from previous studies of the effects of lead on children.
To begin with, Needleman and his group did not measure the amount of lead in the children's blood. That measure can change in a mateer of days, is known to be higher in the summer than in the winter, and does not indicate a child's long-term exposure to lead.
Rather, the researchers had the children's teachers collect baby teeth from the children, then measured the amount of lead in the pulp of the teeth, one of the places where lead collects in the body.
Additionally, the study matched the "high lead" and "low lead" groups 39 different ways to eliminate the possibility that something other than lead exposure might account for differences between the children.
Among other things, Needleman matched the two groups of children by the socio-economic status of their parents, the IQs of the parents, the parents' educational levels, whether or not the father was in the home, the children's past medical histoy, their physical size and parental aspirations for the child, attitude toward the child and home learing environment.