Lead Levels Put 25% of Southland Children at Risk

More than 25% of Southern California children--and more than 40% in the San Diego metropolitan area--may have levels of lead in their blood that could diminish learning ability and cause behavioral problems, according to a national study made public Monday.

Nearly 60% of the children in the Los Angeles-Long Beach area are estimated to have lead levels that could impair learning, according to the study, which found rates to be at least 33% in seven California population areas of 1 million or more people.

The study by the Environmental Defense Fund is the first to calculate the potential lead exposure to children in specific U.S. metropolitan areas. The report used estimates from the U.S. Agency for Toxic Substances and Disease Registry, whose data was based on the number of young children, ages 6 months to 5 years, living in older houses where lead-based paint is usually found, on family income levels, and on some screening programs that relied on blood tests to measure lead levels.

“Lead poisoning is beyond question the single most significant preventable disease of environmental origin in the United States,” Ellen K. Silbergeld, a toxicologist on the staff of the 100,000-member environmental organization, said at a Washington news conference. “Over 3 million children currently have levels of lead in the toxic range. They are not at risk for disease--they have lead toxicity.”

About 58% of the children in the Los Angeles-Long Beach area and at least a third in San Diego, Orange, Riverside, San Bernardino and Santa Barbara counties were estimated to have lead levels of more than 10 micrograms per deciliter of blood, an amount that generally produces no physical symptoms but can reduce by four to seven points a child’s performance on IQ tests. About a quarter of the Ventura County children were estimated to have lead at those levels.

Although the study did not actually measure the lead in the blood of all urban children, the findings largely confirmed, within a 5% margin, the results of smaller investigations that did take blood tests.

The Centers for Disease Control now recommend intervention at levels of 25 micrograms per deciliter of blood. But recent epidemiological studies that found damage at levels as low as 10 and 15 micrograms have prompted the CDC to review its guideline. It is expected to be lowered within a year.

In the San Diego metropolitan area, 40.3% of the children were estimated to have lead levels of more than 10 micrograms while 12.6% were estimated to have levels of at least 15 micrograms, according to the study.

In the Los Angeles-Long Beach metropolitan area, 21% of the young children were estimated to have levels greater than 15 micrograms. A recent state public health investigation that relied on blood samples of young children in Compton and Wilmington found that 20% of the youngsters had levels of at least 15 micrograms, the lowest level examined in the study.

Dr. Lynn Goldman, a pediatrician and epidemiologist who heads the California Department of Health Services section that did the Compton and Wilmington testing, said she had not examined the methodology used in Monday’s report but found its numbers “not surprising.” The U.S. public health survey from which the environmental group extrapolated its figures contained “reasonable” assumptions, she said.

She noted, however, that the environmental group’s estimates may “reflect the highest-risk areas” in some communities. For example, she said, a recent investigation by her section found 17% of the children in a “high-risk” Oakland neighborhood had levels of at least 15 micrograms of lead per deciliter of blood.

By comparison, Monday’s report estimated that 19.7% of all young children in the San Francisco-Oakland metropolitan area have such levels. Goldman said she would have expected the level in the entire region to be lower, not higher, than the Oakland neighborhood, which contained mostly older, dilapidated housing.

Karen L. Florini, an attorney for the environmental group, acknowledged that the estimates could be high for some regions. But she said they also may be too low for other regions because they fail to take into account additional exposure from lead smelters or other lead-producing industries in some communities.

“We’re not trying to say that you would get these specific numbers if you tested the children,” she said. “But even if they were 50% too high, they still indicate an epidemic by anybody’s definition.”

It is virtually impossible to determine the extent to which an individual child may be impaired at exposures of 10 or 15 micrograms of lead per deciliter of blood. Some children, because of such factors as nutrition and genetics, may not be affected while others will perform poorly in school as a result of the same exposure. Moreover, the loss of a few IQ points may not make a great difference in a child’s ultimate achievements.

It is only when large populations are studied that significant differences and reasons for concern emerge. Lead exposure in a large population will significantly reduce the number of those with superior intelligence and increase the number with below-average intelligence.

Banned for most uses in 1977, lead-based paint still can be found in millions of American homes. Children usually are exposed through household dust contaminated by peeling, flaking or chalking paint. Young children also may be poisoned during teething by mouthing on window sills that contain leaded paint.

In addition to reducing IQ, lead in young children can impair reaction time and the ability to concentrate and cause short-term memory loss. The longer the exposure, the greater the damage. Impairment is believed to be permanent, even after a child’s lead levels are reduced to relatively low amounts.

At congressional hearings later this week, the Environmental Defense Fund will propose creation of a $1.5-billion-a-year trust fund to remove lead-based paint from housing. The money would be raised through an excise tax on the production and importation of lead. Estimated costs for professional removal of lead-based paint from residences run between $2,000 and $10,000 a unit.

Dolan reported from Los Angeles and Abramson from Washington.

LEAD LEVELS IN CALIFORNIA CHILDREN

Chart shows the percentage of children ages 6 months to 5 years who are projected to exceed selected blood lead levels, broken down in selected population groups. Figures are expressed in micrograms of lead per deciliter of blood (MCG/DL). The federal Centers for Disease Control is currently reviewing its definition of “lead toxicity,” now set at 25 micrograms per deciliter of blood. The CDC is expected to adopt a new definition of 10 to 15 micrograms per deciliter within the year.

Population Area Percentage Percentage (Over 1 Million) Over 10 MCG/DL Over 15 MCG/DL Los Angeles-Long Beach 58.2 21.0 San Francisco-Oakland 55.5 19.7 Sacramento 40.9 12.9 Riverside-San Bernardino-Ontario 40.6 12.3 San Diego 40.3 12.6 San Jose 35.3 10.0 Anaheim-Santa Ana-Garden Grove 33.1 9.3

Population Area Percentage Percentage (Under 1 million) Over 10 MCG/DL Over 15 MCG/DL Fresno 40.9 11.9 Stockton 38.1 11.9 Salinas-Seaside-Monterey 37.1 10.7 Santa Barbara-Santa Maria-Lompoc 34.3 9.0 Bakersfield 34.1 9.4 Vallejo-Fairfield-Napa 31.5 9.5 Modesto 31.2 8.5 Oxnard-Simi Valley-Ventura 27.3 7.2

Source: Environmental Defense Fund