Demetria Riley moves with the boundless curiosity of a 4-year-old, exploring every nook of her surroundings like TC detective unraveling a mystery. But something isn't right. She slurs her words slightly. She hasn't acquired language as fast as her peers and often has to repeat sentences to make herself understood.
Two years ago, during a routine physical examination, a doctor tested her blood for lead and discovered that she was accumulating dangerous levels of the toxic metal. Her mother, Betty Davis, said she was concerned about her daughter's speech problems but was shocked to learn the cause. The symptoms were so subtle, she said, so easily mistaken for the normal fits and starts of a developing child.
"This is the kind of child who can really fool you," said Mary Snyder-Vogel, a social worker at the Kennedy Institute, where the girl has been hospitalized four times for treatments aimed at reducing the concentrations of lead in her blood.
"You probably never would have known the difference without screening," said Dr. Julian Chisolm, the Kennedy Institute's nationally known specialist in lead poisoning. But if her lead levels were allowed to increase, he said, Demetria could become crippled with severe and lifelong symptoms ranging from anemia to seizures.
Cases like Demetria's prompted Health and Human Services Secretary Louis W. Sullivan to issue wide-ranging guidelines last week that recommend, among other things, lead screening for every child. He also lowered the threshold for safe levels of the metal -- bringing an estimated 4 million children into the risk category.
The new threshold of 10 micrograms of lead per deciliter of blood is not a legal standard; it is the level at which many scientists think lead begins to dull intelligence and stunt growth and hearing.
Dr. Sullivan did not recommend medical intervention for children with levels of 10 to 14 micrograms. Rather, he recommended public efforts to prevent lead poisoning in communities where many such children live. Children with levels of 15 to 19 micrograms should receive nutritional counseling and more frequent screening, he said, and children with higher levels should be medically evaluated and the source of their lead exposure found and removed.
Close to home, the implications are dramatic. In Baltimore, 60 percent of the children below age 6 would test above the new threshold, according to the state Department of Environment. Statewide, an estimated 10 percent of all children in that age range exceed the old threshold of 25 micrograms; the new threshold increases the percentage to 50 percent.
But only one-fifth of the children in Maryland are tested routinely for lead. Like Demetria, many of them are enrolled in Medicaid, which recently required doctors to provide preventive care that includes lead screening.
The call for universal screening came on the heels of scientific studies tracing lifelong learning problems to low-level lead poisoning during early childhood. A recent study, based on an 11-year follow-up of 132 children living near Boston, found that low-level exposure reduced IQs in some children and impaired speech, language skills and attention span.
"The important thing is not to panic people," said Dr. Herbert Needleman, a University of Pittsburgh professor who led the study. "We're not in the middle of a plague, but it's an important situation, and we need to make a frontal attack."
Lead has been removed from gasoline, interior paint and most canned food sold in the United States. But children still get poisoned by its legacy: peeling paint, dust that settles on floors, baseboards and windowsills, and dirt that carries paint residue and gasoline drippings.
Most of the Maryland children in the risk category are contaminated with relatively low levels of lead that could cause them to have a tougher time at school.
"You'd find lower intellectual function, and you'd find disturbances in attention," Dr. Needleman said. "But they're probably nothing visible to the human eye, and probably not every kid is going to be affected, even if you were to scrutinize them in depth."
The toll exacted on individual children has a cumulative effect on society, some experts say.
"We have a real problem in this country with adult literacy, which is impacting the work force," said Pat McLain, who directs the Maryland Department of Environment's program for preventing lead poisoning. "It's important to protect the economic future of our country. If they can't become productive citizens and compete in the world market, we will all be worse off."
Noticeably absent from the federal guidelines is a blueprint for how to put them into effect. Dr. Sullivan indicated that states and localities share much of the responsibility to attack the lead problem. That left many advocates for children and state officials to wonder how the campaign could be undertaken in an era of tightening budgets.