A few decades ago, Americans just weren't that worried about lead. They breathed fumes from leaded gasoline and painted their houses with lead-based paint. Some even drank water from lead pipes and ate food from lead containers.
Thanks to massive public health efforts and successful campaigns to remove lead from gasoline and paints -- not to mention recent efforts to recall toys and other products tainted with lead -- severe lead poisoning isn't nearly as common as it used to be. The typical lead levels found in the blood of children under 5 in the United States dropped nearly 15-fold between the late 1970s and the late 1990s.
Ironically, the triumph against lead also exposed how dangerous it continues to be. Once doctors started seeing more and more kids and adults with relatively small amounts of lead in their systems, it became clear that even a little bit of lead could cause serious damage. Young bodies are especially vulnerable. At a time when they should be stockpiling nutrients for growth, too many kids are still collecting lead in their blood, bones, and brains.
The consequences -- behavioral, intellectual, and physical -- may last a lifetime. According to a report in the journal Pediatrics, 25 percent of all kids live in homes or communities that put them at serious risk for an overdose of lead. And by the estimates of the Centers for Disease Control and Prevention (CDC), more than 250,000 kids in the United States already have potentially dangerous levels of lead in their bodies.
Lead isn't as ubiquitous as it used to be, but this is no time for anyone to let down their guard, says Valerie Charlton, MD, chief of the Childhood Lead Poisoning Prevention Branch of the California Department of Health Services. "It's especially important for parents to be educated about the risks of lead," she says. If there's a child eating, breathing, and playing in a home, it's up to parents to get the lead out.
Lead: A lasting hazard
Like other basic elements, lead never disappears. It simply moves from one place to another. The lead that spewed from the tailpipe of a Ford Mustang in 1975 is still out there. Some of it may have settled on a patch of dirt or a driveway. And some of it may still be in the body of a former neighborhood kid.
That's the problem with lead: Once it gets into the body, it tends to stick around. Unlike calcium and iron, two metallic elements that are vital to health, lead has absolutely no biological function. But because lead is chemically similar to calcium and iron, cells eagerly suck it up. The impostor ends up taking the place of the useful metals, throwing a wrench into systems throughout the body.
Lead is especially toxic to young brains. Studies suggest that just a small amount of lead exposure during the toddler years may permanently shave off 5 to 7 points of a child's IQ. According to Charlton, early exposure to lead can also increase the chances of learning problems, attention deficit disorder, truancy, and trouble with the law.
Lead exposure affects adult brains, too. Small amounts have been linked with memory problems, disturbed sleep, and swings in personality and mood. As reported in a 2007 issue of International Review of Psychiatry, exposure to lead in younger years may contribute to so-called "age-related" memory problems decades down the road. Some experts believe that lead may also increase the risk of Alzheimer's disease. A 2008 study published in the Journal of Neuroscience found that monkeys developed a condition very similar to Alzheimer's disease if they were exposed to lead as infants.
The dangers of lead reach beyond synapses and nerves. According to the Environmental Protection Agency, lead can stunt a child's growth, damage hearing, increase blood pressure, impair fertility in both men and women, and cause headaches and muscle aches. At extremely high levels, it can cause seizures and even death in both children and adults.
Finding the source
No matter how much lead a child or adult may be carrying around -- or how sick they might be as a result -- doctors can't diagnose lead poisoning based on symptoms alone. "What's so insidious about lead is that the signs are very subtle," Charlton says. "A blood test is the only way to confirm exposure." Parents should request a test if they suspect their child may have been exposed to lead -- perhaps by chewing old paint chips or swallowing a metal toy -- or if a sibling or neighbor has already been diagnosed with an overload of lead. Doctors are now required to check lead levels of all children age 1 to 2 receiving any kind of government assistance such as Medicaid.
If tests show that a child has too much lead -- just 10 millionths of a gram per liter of blood can be enough to signal danger -- it's time to consider the source. According to the EPA, children most often get lead in their systems from one of three places: house paint, soil, or dust. House paint sold before 1978 often contained high levels of lead, and countless small children over the years have put paint chips in their mouths. Soil can contain lead released from cars or factories decades ago. Flaking paint and dirt tracked into the house can add lead to household dust.
In recent years, government agencies, retail stores, and consumer watchdog groups have been cracking down on lead-tainted toys, another potential source of lead poisoning. Millions of toys -- many of them made or assembled in China -- have been recalled in recent years because of high levels of lead in paint or toxic magnetic parts. Examples include several types of red-painted trains from the popular Thomas the Tank Engine train sets, a painted die-cast car modeled after "Sarge" from the movie Cars, and toy robots from a company called OKK trading. (The U.S. Consumer Product Safety Commission lists toys recalled for lead or other safety reasons at http://www.cpsc.gov/cpscpub/prerel/category/toy.html.)
Many kids get their lead from another source: Their parents. Adults whose work involves soldering, metal salvage, old home repair, sandblasting, and other jobs often come home coated with a thin layer of lead. They need to wash up and change clothes before they go home and hold their baby or come in contact with any family members, Charlton says.
Over the years, a few less common sources of lead poisoning have been uncovered. Kids have become ill after swallowing fishing sinkers, curtain weights, and cheap metallic jewelry sold in vending machines, and candy jam from Mexico packed in ceramic pots. Imported lead-glazed pottery has also been implicated in a lead-poisoning outbreak in a Westchester County, New York, family. Various traditional folk remedies and cosmetics may also contain harmful amounts of lead, although documented cases of lead overdoses from these sources are rare.
Some immigrants may also have increased lead levels because of where they were born or the imported food they eat. According to a 2000 study of 452 children adopted from China published in the journal Pediatrics, 14 percent showed elevated lead levels. But China isn't the only country where lead poisoning is suspected. According to the CDC, children from Russia may also suffer high rates of lead poisoning.
Protecting kids from lead
If you're a parent with concerns about elevated lead levels, particularly if you have young children, you should talk to your doctor. Make sure to ask for a lead test if you know of a specific risk. If your kid has undetectable levels, that will be reassuring, and you may be able to relax a bit.
Once a child has been harmed by lead, even the best medical treatment may not be able to fully undo the damage. The only real way to protect kids -- and everyone else in the family -- is to keep lead out of their lives.
For starters, parents should never let children chew on paint chips or suck on painted toys. As Charlton explains, most of the lead in a kid's body enters through the mouth. House paint bought before 1978 -- the year the federal government dramatically reduced allowable levels of lead in paint -- is especially dangerous. But even if the paint on a toy or on the living room wall meets current federal standards for lead, you still want to keep that paint out of your child's mouth.
According to the FDA, children shouldn't consume more than 6 micrograms -- that's six millionths of a gram -- of lead each day. At the same time, the Consumer Products Safety Commission allows paint to contain up to 0.06 percent lead. That means that just one gram of paint each day can push a child to the very edge of a lead overload.
In recent years, many concerned parents have purchased home lead-testing kits to check for lead on toys, walls, and other places. But such kits may give a false sense of security. The Consumer Product Safety Commission recently put widely available kits to the test using objects containing various levels of lead. In more than half of all tests, the kits wrongly suggested that the objects were free of lead.
In the home, a good paint job is an excellent defense against lead. Even though older layers of paint can be loaded with the metal, no one will be in much danger if the paint is clinging tightly to the wall. Charlton says all parents should watch out for flaking or peeling spots of paint. Sealants and a fresh coat may temporarily reduce the threat -- and the walls will look better, too.
Unfortunately, other types of "home improvement" projects can increase the danger of lead poisoning. Scraping paint or cutting through a wall can spread lead throughout a room. "A huge number of people who work on their homes don't know what they're doing," Charlton says. Parents who are planning a major project that could disturb old layers of paint, or who would like to permanently remove a lead paint hazard such as chipped or peeling walls, should hire a licensed contractor who has experience in handling lead hazards or has taken a course to become a certified lead abatement worker. The National Lead Information Center (http://www.epa.gov/lead/pubs/nlic.htm) can provide a list of qualified professionals in the area.
If a family lives in an older home with water pipes that may contain lead or lead solder, parents should use only cold water for drinking, cooking, and baby formula; it's less likely to contain lead. If there's lead in the pipe at the street, known as the "header pipe" -- and the water in the pipes has been standing for more than six hours -- parents will need to let a large tap such as the shower run for at least five minutes and then run the cold water at the sink for an additional 12 minutes before using.
Parents should also take a hard stand against dust and dirt. Charlton recommends wet mopping at least once a week to keep dust levels down. It's a good idea to regularly clean toys, too. Any big patches of bare dirt in the yard should be covered up. And kids should wash their hands before eating -- good advice no matter how much lead might be around.
Lead poisoning isn't as common as it used to be. That's reason to be grateful, but it's no reason to ignore the danger that still exists.
Interview with Valerie Charlton, MD, chief of the Childhood Lead Poisoning Prevention Branch of the California Department of Health Services. 2008.
U.S Environmental Protection Agency (EPA). Lead poisoning: a historical perspective. 2009. http://www.epa.gov/history/topics/perspect/lead.htm
Committee on Environmental Health. Lead exposure in children: Prevention, Detection, and treatment. Pediatrics. October 2005. 116 (4): 1036-1046.
Mowad, E., I. Haddad, and D.J. Gemmel. Management of lead poisoning from ingested fishing sinkers. Archives of Pediatrics and Adolescent Medicine, Vol. 152(5):485-8.
Consumer Product Safety Commission. What You Should Know About Lead Based Paint in Your Home: Safety Alert. http://www.cpsc.gov/CPSCPUB/PUBS/5054.html
Centers for Disease Control and Prevention. Sources of Lead: Water. http://www.cdc.gov/nceh/lead/tips/water.htm
U.S. Environmental Protection Agency. Lead in Paint, Dust, and Soil. August 17, 2010. http://www.epa.gov/lead/pubs/leadinfo.htm
Schwartz, B.S. and W.F. Stewart. Lead and cognitive function in adults: a questions and answers approach to evidence of cause, treatment, and prevention. International Review of Psychiatry. December 2007. 19 (6):671-692.
Wu, J. et al. Alzheimer's Disease (AD)-Like Pathology in Aged Monkeys after Infantile Exposure to Environmental Metal Lead (Pb): Evidence for a Developmental Origin and Environmental Link for AD. The Journal of Neuroscience. January 2008. 28(1):3-9.
Wright, R.O., M.W. Shannon, et al. Association between iron deficiency and low-level lead poisoning in an urban primary care clinic. American Journal of Public Health. 1999;89:1049-1053
U.S. National Library of Medicine. Tox Town: Lead. September 28, 2010. http://toxtown.nlm.nih.gov/text_version/chemicals.php?id=16
Khan, A.N. Lead Poisoning Imaging. February 3, 2009. http://emedicine.medscape.com/article/410113-overview
U.S. Consumer Product Safety Commission. Toy Hazard Recalls. 2010. http://www.cpsc.gov/cpscpub/prerel/category/toy.html
Miller, Laurie C. MD and Nancy W. Hendrie MD, Health of Children Adopted from China. Pediatrics Vol. 105 No. 6 June 2000 http://pediatrics.aappublications.org/cgi/content/full/105/6/e76
Centers for Disease Control and Prevention. Elevated Blood Lead Levels Among Internationally Adopted Children -- United States, 1998. http://www.cdc.gov/MMWR/preview/mmwrhtml/mm4905a3.htm
California Department of Health Services. State Health Department Issues Health Warning on Lead-Contaminated Chapulines (Grasshoppers). November 13, 2003.
Lead Inspector lead test kit. http://www.leadinspector.com/?gclid=CN3f-5bhx5MCFRYesgodbC5ojg
Minnesota Department of Health. Testing the Home for Lead to Prevent Exposure to Lead. http://www.health.state.mn.us/divs/eh/lead/homes/testlead.html
Centers for Disease Control and Prevention. Lead. Last updated October 28, 2010. http://www.cdc.gov/nceh/lead/