Study Finds Perilous Level of Lead in 20% of Children

Twenty percent of young children studied in Compton and Wilmington were found to have potentially hazardous levels of lead in their blood--amounts that may be high enough to cause behavioral and learning disorders, according to a report made public Thursday by state health authorities.

The children, 90% of them Latino, were believed to have ingested the lead from dust in their homes or soil contaminated with lead from car exhausts, nearby lead-emitting industries or flaking exterior paint.

“It could mean that they (the children) will have long-term, potentially irreversible neurological damage,” said Mary Haan, an epidemiologist and project director of the state Department of Health Services’ childhood lead program.

Haan said the report is the first to show significant lead exposure in California children. She said surveys conducted more than a decade ago were poorly done, and screened primarily for higher levels.

The number of cases is likely to surprise many health professionals because it has widely been assumed that lead poisoning is rare in California, which has a relatively new housing stock. Nationally, experts have estimated that 17% of urban children have the potentially dangerous level of lead, compared to the 20% in the Los Angeles study.

Last year, a congressional subcommittee found that components in certain water coolers and drinking fountains were made of lead. Schools districts nationwide immediately began testing fountains, and reports of high levels of the metal in some locations raised new fears.

But the report Thursday by the state Health Services Department shows for the first time that lead is a problem in many California homes, primarily because of old paint and lead-laced household dust. The findings are of particular concern because experts now believe that much smaller amounts of lead in children cause health problems than was previously believed.

State workers tested 487 Los Angeles County and 551 Oakland children, ages 1 to 6, in their homes from October, 1987, to September, 1989, and analyzed interior paint and the soil in their yards for lead content. In Oakland, the highest lead levels coincided with high levels in paint and soil. The Southern California data on paint and soil have not yet been analyzed.

The study found that 20% of the Los Angeles County children and 19.1% of the Oakland youngsters had at least 15 micrograms of lead per deciliter of blood. A very small proportion of them had blood levels of 25 micrograms or more, the amount which the Centers for Disease Control considers high enough to warrant medical intervention. Recent studies, however, have shown harmful effects at levels as low as 15 and even 10, and the CDC is expected to lower the so-called “action level” as a result.

“The evidence on follow-up studies of kids with these blood lead levels (suggests) the types of neurological effects are not reversible,” Haan said. “So, in practical terms, it may mean poor school performance and more behavioral problems.”

No study has followed the children through adulthood, so it is still uncertain if the damage is permanent. There is evidence, however, that impairment at lower levels persists at least for several years, particularly for infants who were exposed in their first months of life or while in the womb.

For the 20% of the children who were found to have lead levels from 15 to 25, there is little that government or physicians can do. Government cannot mandate abatement of lead in Los Angeles County homes unless the level is at least 25, and there is generally no medical treatment for exposure at lower levels. For the 1.3% of the children in both Oakland and Los Angeles County whose blood lead level was 25 or above, the state contacted their pediatricians or county health authorities to ensure that the children received follow-up treatment, which could range from vitamin supplements to hospitalization.

“Of course, the parents are very concerned about this,” Haan said, “but they haven’t reacted en masse in any way. . . . We tend to do surveys in areas where people have a lot of problems besides this, and it may not be on top of their priorities.”

Children are considered more vulnerable to lead than adults because of differences in metabolism and excretion of the substance. Adults absorb about 10% of the lead they ingest, while children absorb about 50%. Young children also explore the world by putting things in their mouth, including toys that may be covered with lead dust or paint chips.

Primarily, lead affects the brain and the rest of the central nervous system. In children, levels between 15 and 25 are believed to delay cognitive development and reduce scores on intelligence tests. The higher the levels and the longer the exposure, the greater the damage, scientists believe. At very high levels--above 100 micrograms per deciliter in children--lead poisoning can cause severe brain damage, including mental retardation, and even death.

The scientists selected the Compton, Wilmington and Oakland neighborhoods as “high-risk” because at least 60% of the housing there was built before 1950, young children live in at least 10% of the homes, 70% of the families have incomes under $15,000, and freeways, busy roadways or lead-emitting industries are located nearby.

Lead content in residential paint has been regulated since 1977, but paint manufacturers began voluntarily reducing lead in household paint in the 1950s because of growing evidence that lead could cause problems. Based on the 1980 Census, it is estimated that more than 2 million homes in California were built before 1950 and therefore may contain lead-based paint.

Based on the number of households with young children and the number of houses built before 1950, the state health report estimates that 3,200 California children under the age of 6 have lead poisoning and another 50,000 may be at risk.

Poorer children tend to outnumber the affluent in poisoning cases because poor nutrition, particularly inadequate iron, leads to greater lead absorption. Higher-income children are not exempt, however. Children of affluent professionals who are scraping off old paint in remodeling older homes can be inadvertently poisoned. Although peeling leaded paint is particularly hazardous, intact paint can give off a dust that can also poison a susceptible child.

In Thursday’s report to the Legislature, state health authorities recommended that a second study of more affluent children be undertaken and that a program to educate pediatricians on lead poisoning be launched. The report also calls for annual lead screening of “high-risk” children, which is recommended by the American Academy of Pediatrics. In California, such routine screening is rare.

In addition, Assemblyman Lloyd G. Connelly (D-Sacramento) has introduced legislation designed to establish procedures for routine blood-lead screening and to aid local health departments in identifying and following up on lead poisoning cases.