Lead Exposure 101
The Hazards of Lead
Maybe it's not true, as pundits were saying a few years back, that lead paint is the new asbestos. Then again, maybe it is.
After fading from public consciousness for a few years, questions about lead's impacts have reemerged, stimulating renewed debate about whether we are appropriately protecting our children -- especially in cities where the sources of lead are both prolific and pervasive and where new awareness of lead poisoning in middle- and upper-income city kids is setting up alarms in the medical establishment. But with public policy makers sparring with children's advocates and scientists often at odds with one another, it's hard to get a fix on what it all means for you.
Physical Effects of Lead
What is incontrovertible is the fact that lead and children do not mix. The absorption, either by ingestion or inhalation, of too much lead by young children (particularly those under 6 whose bodies absorb more of it than older kids or adults when exposed) can result in the development of severe physical problems -- damaged kidneys and central nervous systems, interference with blood cell formation, even death. Clearly, this is not something to trifle with.
Cognitively, it's ugly too. Children with high blood lead levels (BLLs) are at greater risk for developmental delays, permanent learning disabilities, fine motor coordination issues, even a drop in IQ. Furthermore, while a causal relationship has not yet been established, there is mounting evidence that lead exposure may be associated with many of the symptoms associated with ADHD.
What is still very much up for grabs is: (1) how much lead in the blood is "safe," (2) what sources of lead are the ones to worry about, and (3) how crazy parents should get about protecting their children against lead.
How Much Lead Is Too Much?
The government has done an excellent job of reducing lead exposure by banning the use of lead-based paint and lead plumbing supplies and through the phasing out of lead in gasoline. The decrease in the incidence of lead poisoning has been dramatic -- 88 percent of children under the age of 6 were found to have had elevated blood levels between 1976 and 1980, compared to just 2 percent (an admittedly soft number) in the survey period running from 1999 to 2000.
But most of these stats measure results under guidelines issued by the Centers for Disease Control and Prevention (CDC) in 1991, which classify toxicity as BLLs of 10 micrograms per deciliter or greater. These guidelines are now under strong attack. Studies by researchers such as Bruce Lanphear, MD, MPH, director of the Cincinnati Children's Environmental Health Center at the Cincinnati Children's Hospital Medical Center and considered by many to be the country's top pediatric lead researcher, have demonstrated that much smaller amounts of lead than those permissible under the current CDC rules could put children at risk for all the cognitive damage excessive lead can wreak.
Is Even 10 Micrograms of Lead Too Much?
In one 5-year study, in which researchers from Cornell University and the University of Rochester School of Medicine participated, children with BLLs below the 10 micrograms per deciliter threshold showed "intellectual impairment" from the lead exposure, with the amount of impairment most pronounced at the lower levels.
What type of impairment? Maybe 5 IQ points at the lower levels, which is not nothing. We wouldn't be at all surprised if new guidelines are eventually issued that will reduce the previous standard for acceptable blood levels in children by as much as 50 percent. But eventually is the operative word here. As Dr. Lanphear warns, "The laws catching up to the science could take a week, a month, or five years..."
Should you care? Well, in the 1970s, when the bulk of today's parents were toddling around, the average BLL for all American kids was 25 micrograms (and look how great we all turned out). But after reading reams of material and talking with many top docs who are so concerned about lead, we believe keeping your kids at very conservative BLLs (below the proposed replacement standard of 5 BLLs) is both warranted and attainable without enormous amounts of effort on your part. Besides, we do all want our children to turn out even better than we did, don't we?
How Does a Child Get Exposed?
Just screening blood is not sufficient. "If it's true that there is no discernible threshold for intellectual impairments, as our studies are showing," suggests Dr. Lanphear, "then our focus must shift away from waiting until a child has been unduly exposed, to primary prevention. First thing I would tell parents: Primary emphasis should be on screening housing and reducing exposures; screening blood should be considered a safety net."
The prevailing wisdom (so far, at least) is that most cases of lead poisoning are the result of exposure in homes, primarily when children in older buildings eat peeling lead paint chips (which have an especially high concentration) that have fallen on the floor or are chipping off walls or window frames. Exposure also occurs when teething toddlers chew on windowsills, doors -- even radiators -- and/or when kids ingest or inhale lead-tinged dust particles that get on their toys, on food that's been stored uncovered, or on the floors on which they're playing.
Is Your Home a Hazard?
Don't ignore your own walls because you think this type of stuff only happens in substandard housing. Lead dust can exist in the most meticulously maintained home and can even be a significant issue in a newly renovated apartment because of the disturbance of old paint. So the antebellum dream house you've been fantasizing about restoring in Atlanta, or that "perfect" 1920s bungalow in Portland? It may turn out to be more of a nightmare for your kids if you don't take precautions.
Sheldon Whitehouse, former attorney general of Rhode Island, found this out the hard way. He and his wife renovated their house in a lovely historic district in Providence. All was well until a routine blood test post-renovation resulted in the stunning news that his children had elevated blood lead levels.
According to recent CDC research, remodeling and repainting projects may be the cause of as much as 10 percent of all lead poisoning in American children. In fact, over the last decade, doctors have been reporting a real shift in the demographics of lead-poisoned children.
Dr. Lanphear notes that only a decade ago, children from the poorest neighborhoods comprised about 90 percent of the cases treated at Cincinnati Children's Hospital Medical Center. Now, he says, a good 50 percent of exposed children treated at his hospital come from affluent families who have been inadvertently poisoned when their old homes were renovated.
So please, do not assume that your child will be immune from lead's deadly effects just because you have nice digs. Nor is it safe to believe that you've protected your child simply because you kept him out of your abode during the renovation itself; lead levels can be persistently high even after the job is completed. (By the way, if you're pregnant, you need to be just as concerned: Lead ingested during pregnancy can have devastating results on the baby's development.)
Lead Outside the Home
There are, of course, other sources of lead intake besides paint, but they tend to be more elusive. According to the American Academy of Pediatrics, for kids with low, but still elevated, blood levels (between 10 and 14 BLLs), the source of the lead exposure is often a mystery.
One possibility is dirt from sidewalks, parks, playgrounds, and building foundations. Howard Mielke, MS, PhD, has been researching the incidence of lead in urban soil over the two decades since his own daughter's high blood lead levels were traced to the soil in her daycare center's outdoor play area. He and other scientists conducting studies in cities as diverse as Baltimore, Minneapolis, and New Orleans, and the results suggest that, in traffic-congested urban areas, "many children face their greatest risk for exposure in the yards around their houses and, to a lesser extent, in the open spaces such as public playgrounds in which they play."
While there's considerable debate as to the sources of urban soil lead -- from traffic exhaust to building paint residue and fallout from industrial pollution -- there's no question that its buildup can be substantial. A Chicago residential neighborhood study documented median soil lead levels more than four times the acceptable EPA standard, causing health professionals at the renowned Children's Memorial Hospital to warn parents that protecting kids from lead in soil should be as important as safeguarding them against paint-based sources.
Lead in Your Water?
Finally, there's the issue of lead found in water. Many cities, including Atlanta, New York, Pittsburgh, Philadelphia, and New Orleans, add an anticorrosive called orthophosphate to the water supply and have achieved great success in reducing the lead content of water found in older buildings, but there are no guarantees. Lead can still leach in from old pipes and from brass fittings on faucets or pipes in your building, particularly if you are using hot water. Washington, D.C., residents are still reeling from the news that two-thirds of tested homes had water exceeding EPA lead limits (some by as much as 36 times), a result of additives which corroded lead pipes.
Should You Be Concerned?
There seems to be little question that urban kids are more at risk for lead exposure than suburban children because they suffer from the unhappy combination of old housing stock and industrial contamination. Certainly some locales seem to have more problems than others.
Cities on record with high incidences of lead poisoning include:
- Boston (though Beantown seems to have cleared up much of the problem with its very stringent lead abatement program)
But it's not just the old-time industrial cities with problems; even San Francisco estimated that 8 percent of its children had elevated blood levels.
When do you really have reason to worry or take action?
- If you live in poorly maintained, inner-city housing.
- If you live in a building built before 1978 -- especially, if the apartment's been renovated or you're doing the renovation.
- If your child plays on dirt at your home, daycare, school, or playground and that area is located near high traffic roads.
- If your child has a BLL of 5 or more.
All content here, including advice from doctors and other health professionals, should be considered as opinion only. Always seek the direct advice of your own doctor in connection with any questions or issues you may have regarding your own health or the health of others.