"Most existing lead standards fail to protect children," said Dr. Jennifer Lowry, author of the policy statement. "They provide only an illusion of safety."
In 2005, the academy first recognized the possibility of lead-associated intellectual impairments at blood concentration levels of 10 or more micrograms per deciliter. (Until recently, this has been the accepted blood lead "level of concern" for children.) Yet now, "extensive and compelling evidence" indicates that cognitive deficits and behavioral problems, including attention disorders and aggression, can occur when blood levels are half that amount.
Among the population as a whole, the impact on children's intellectual abilities is substantial. One study estimates that lead toxicity accounted for a loss of 23 million total IQ points among a six-year cohort of American children.
According to Lowry, the best "treatment" is to prevent lead exposure before it happens, since the effects of lead on the brain are irreversible. Still, she says, the overall impact can be overcome with good education and good nutrition.
The developing brains of children are most vulnerable to the neurotoxic effects of this metal, which is able to pass through both the placenta and the blood-brain barrier. Lead exposure can cause spontaneous abortion, low birth weight and reduced growth in children.
Though lead affects every organ in the body, the nervous system is most susceptible. At very high blood lead levels, vomiting, seizures and even death can result.
The steady march of federal policy to banish lead from households and consumer products, which began in 1971, has yielded positive results. Over the past four decades, the elimination of lead from paints and gasoline has resulted in dramatic declines in blood concentration levels in children.
Yet the toxic metal remains in our environment, including in these surprising places:
"Lead from paint, including lead-contaminated dust, is one of the most common causes of lead poisoning," finds the Environmental Protection Agency
Before the late 1970s, paint-makers routinely added the toxic metal to their products to boost color and coverage ability. The first major legislation banning the use of lead was the Lead-Based Paint Poisoning Prevention Act of 1971, which addressed its use in federal housing
(PDF). Some individual states banned residential use of lead-based paint shortly after, but it wasn't until 1978 that the ban on residential paint received approval.
A recent national survey of housing estimates that slightly more than a third of homes across the nation have lead-based paint somewhere in the building, the majority of them built before 1978. Lead-based paint buried beneath protective layers of newer paint is not likely to cause a problem. However, any renovation project that disturbs surface layers of paint could lead to poisonous exposure. Windows are often most contaminated, since external paints tended to contain higher concentrations of lead.
Water: Drinking water is another possible source of lead contamination. Though the toxic metal is not usually found in natural water supplies, such as lakes, it can enter water distribution systems and household plumbing due to corrosion. In particular, lead-based soldering to join pipes to water mains and pipes to faucets was allowed until a 1986 congressional prohibition limiting these practices. (Solders of greater than 0.2% lead and plumbing materials of greater than 8% lead are banned.)
Construction that is older than 1986, then, may still contribute lead to drinking water.
"Drinking fountains in older schools
can be an important source of lead exposure," notes the American Academy of Pediatrics. Unfortunately, most states still lack regulations for examining school drinking fountains
Food: Whether home-grown or mass-produced, food may also be lead-tainted. Vegetables grown in soil contaminated with lead from paint dust or fuel exhaust will be similarly tainted. Lead can leach directly into food packaged in tins manufactured using lead soldering. Leaded crystal glassware and lead-glazed pottery bowls and dishes may also taint food. Each additional step of food packaging, preparation and storage also may contribute contamination to the foods you eat.
Imported candies, particularly those containing tamarind, chili powder or certain salts, may have elevated levels of lead. Candies imported from Mexico, Malaysia, China and India are most likely to be tainted, says the California Department of Public Health
. The precise origin of lead in these products is not clear, though improper processing or storage of ingredients may be to blame.
Everyday items -- including older or antique furniture, imported glazed ceramics and crafts -- can serve as camouflage of this metallic poison. Specifically, old paints and glazes used to make these items may contain lead. Non-glossy vinyl mini-blinds imported from China, Taiwan, Mexico and Indonesia may contain lead, according to the Consumer Product Safety Commission
. As the blinds deteriorate, dust forms on the slats, which children are likely to ingest.
Costume pieces, inexpensive metal amulets and baubles found in vending machines sometimes test positive for lead. Naturally, small children often place these innocent-seeming necklaces, rings and jewels in their mouths. The American Academy of Pediatrics notes that one child died in 2006 after swallowing a metal heart charm that came with a pair of Reebok shoes; the child, who first appeared in the hospital vomiting and complaining of a stomachache, died after four days on life support. The medical examiner reported
that the charm was 99.1% lead.
Toys: Items made especially for kids sometimes contain lead. Lunchboxes and crayons may be contaminated, while toys passed down from parents to children may be colored with lead-based paints. Although for most kids, these products represent only a small source of possible intake, the American Academy of Pediatrics finds that they can be the major source for an individual child.
Folk remedies and cosmetics: Folk remedies for ailments including rashes, fevers and upset stomachs may contain lead. In particular, health officials point to Ayurvedic medications and other remedies imported from India, Southeast Asia, the Middle East, the Dominican Republic and Mexico. Additionally, some cosmetics, including kohl for outlining the eyes, may contain the toxic metal.
"We must not treat children as 'canaries in the coal mine' where they are exposed first and then tested to see if they have been poisoned," Lowry said.