Lead poisoning occurs when a person swallows, absorbs, or inhales the element lead in any form. The result can be damage to the brain, nerves, and many other parts of the body. Chronic lead poisoning—a common problem in children—occurs when small amounts of lead are taken in over a longer period. Acute lead poisoning, which is somewhat rare, occurs when a relatively large amount of lead is taken into the body over a short period.
Lead can damage almost every system in the body. It is particularly harmful to the developing brain of fetuses and young children. The higher the level of lead in a child's blood and the longer this elevated level lasts, the greater the chance of ill effects. For 20 years, the Centers for Disease Control and Prevention (CDC) defined childhood lead poisoning as a whole-blood lead concentration equal to or greater than 10 micrograms/dL. In May 2012, the CDC redefined lead poisoning as a whole-blood lead concentration equal to or greater than 5 micrograms/dL. Using this lower definition, the CDC projects that an additional 1 million American children could be diagnosed with lead poisoning.
Over the long term, lead poisoning in a child can lead to learning disabilities, behavioral problems, and even mental retardation. At very high levels, lead poisoning can cause seizures, coma, and even death.
Before scientists knew how harmful lead could be, it was widely used in paint, gasoline, water pipes, and many other products. Today house paint is almost lead-free, gasoline is unleaded, and household plumbing is no longer made with lead materials. Still, remnants of the old hazards remain. Following are some sources of lead exposure:
Children with an increased risk of lead poisoning include those who
Lead testing is also important for adults whose job or hobby puts them at risk for lead poisoning. This includes people who take part in the following activities:
Lead poisoning is the most common environmental illness in the United States. About 250,000 children in the United States had a high level of lead in the blood according to the old definition of lead poisoning. As many as 1 million more chidren may be classified as having high lead levels under the subsequent, more stringient, definition. Many of these children are exposed to lead through peeling paint in older homes. Others are exposed through dust or soil that has been contaminated by old paint or past emissions of leaded gasoline. Since children between the ages of 12–36 months are apt to put things in their mouths, they are more likely than older children to take in lead. Pregnant women who are exposed to lead can pass it along to the fetus.
Lead poisoning cases are not evenly distributed throughout the population. Although there appear to be no biological factors predisposing any particular racial or ethnic group to lead poisoning, certain racial and ethnic groups have a higher percentage of lead poisonings because of their environmental circumstances. Hispanics, African Americans, and new immigrants are more likely to live in inner cities, in older, dilapidated housing, or near toxic industrial sites, all of which increase their risk of exposure to lead. In children, males and females are equally likely to develop lead poisoning. In adults, men with lead poisoning outnumber women primarily because more men work in industries where they are exposed to lead.
Internationally, lead poisoning has been reported in almost every country in the world. The rate of lead poisoning is much higher in developing countries than in developed ones. Reasons for this include more recent use of leaded gasoline, more occupational exposure, and less strict environmental and occupational safety regulations in developing countries.
Chronic lead exposure is also harmful to adults, in whom it can cause hypertension (high blood pressure), digestive problems, nervous system disorders, memory loss, and muscle and joint pain. In addition, chronic exposure to lead in the environment has been found to speed up the progression of kidney disorders in patients without diabetes. It also can lead to difficulties during pregnancy, as well as cause reproductive problems in men and women.
Acute lead poisoning, while much less common, shows up more quickly and can be fatal. Symptoms such as the following may occur:
A high level of lead in the blood can be detected with a simple blood test. In fact, testing is the only way to know for sure if children without symptoms have been exposed to lead, since they can appear healthy even as long-term damage occurs. The CDC recommends testing all children at 12 months of age and, if possible, again at 24 months. Testing should start at six months for children at risk for lead poisoning. Based on these test results and a child's risk factors, the doctor will then decide whether further testing is needed and how often. In some states, more frequent testing is required by law.
The first step in treating lead poisoning is to avoid further exposure to lead. For adults, this usually means making changes at work or in hobbies. For children, it means finding and removing sources of lead in the home. In most states, the public health department can help assess the home and identify lead sources.
If the problem is lead paint, a professional with special training should remove it. Removal of lead paint is not a do-it-yourself project. Scraping or sanding lead paint creates large amounts of dust that can poison people in the home. Lead in this dust can stay around long after the work is completed. In addition, heating lead paint can release lead into the air. For these reasons, lead paint should only be removed by someone who knows how to do the job safely and has the equipment to clean up thoroughly. Occupants, especially children and pregnant women, should leave the home until the cleanup is finished.
Medical professionals should take all necessary steps to remove bullets or bullet fragments from patients with gunshot injuries.
Changes in diet are no substitute for medical treatment. However, getting enough calcium, zinc, and protein may help reduce the amount of lead the body absorbs. Iron is also important, since people who are deficient in this nutrient absorb more lead. Garlic and thiamine, a B-complex vitamin, have been used to treat lead poisoning in animals.
Lead poisoning is a public health concern addressed by multiple agencies in the United States. For example, the FDA is responsible for detecting high lead levels in foods, including foods imported into the United States. The Environmental Protection Agency is responsible for clean up of toxic waste (superfund) sites that are contaminated with lead and many other chemicals that negatively affect health. The Occupational Health and Safety Administration (OSHA) is responsible for monitoring exposure to lead and other toxic substances in the workplace.
The Consumer Products Safety Commission has played a major role in protecting consumers, particularly children, from lead exposure in common consumer products, especially those made in China. For example, the summer of 2007 saw a record number of recalls of millions of toys made in China, primarily because of high levels of lead. Affected were several of the leading United States toy companies. In August 2007, Fisher-Price recalled one million toy products, including popular Sesame Street characters, Dora the Explorer, and Go, Diego, Go. That same month, Mattel recalled millions of toys involving such high-profile brands as Barbie, Sarge die-cast cars, Doggie Day Care, and Polly Pocket Play Sets, according to the U.S. Consumer Product Safety Commission. Worldwide, Mattel recalled 18.2 million Chinese-made toys as of September 2007, including nearly 10 million in the United States. In November 2007, at the start of the holiday buying season, Kmart removed jewelry from its stores that had been advertised as lead-free after extremely high concentrations of lead were found in some pieces. In some cases, more than half of the jewelry's content was lead.
Recalls for excessive lead content are ongoing. Consumers can find a complete and continuously updated list of lead-related recalls at the Consumer Products Safety Commission's website at http://www.cpsc.gov/cgi-bin/haz.aspx .
If acute lead poisoning reaches the stage of seizures and coma, there is a high risk of death. Even if the person survives, there is a good chance of permanent brain damage. The long-term effects of lower levels of lead can also be permanent and severe. However, if chronic lead poisoning is caught early, these negative effects can be limited by reducing future exposure to lead and getting proper medical treatment.
Many cases of lead poisoning can be prevented. These steps can help.
See also Lead .
Gosselin, Jack D., and Ike M. Fancher, eds. Environmental Health Risks: Lead Poisoning and Arsenic Exposure. New York: Nova Science Publishers, 2009.
Centers for Disease Control and Prevention. “Lead.” June 25, 2012 [accessed June 26, 2012]. www.cdc.gov/nceh/lead
Kathuria, Pranay. “Lead Toxicity.” Medscape.com January 19, 2012 [accessed June 25, 2012]. http://emedicine.medscape.com/article/1174752-overview
“Lead and Human Health.” U. S. Department of Health and Human Services March 20, 2012 [accessed June 25, 2012]. http://sis.nlm.nih.gov/enviro/lead.html
“Lead Poisoning.” MedlinePlus May 12, 2012 [accessed June 25, 2012]. http://www.nlm.nih.gov/medlineplus/leadpoisoning.html
National Lead Information Center, 422 S. Clinton Ave., Rochester, NY, 14620, (800) 424-5323, Fax: (585) 232-3111, http://www.epa.gov/lead/pubs/nlic.htm .
National Safety Council, 1121 Spring Lake Drive, Itasca, IL, 60143-3201, (630) 285-1121, (800) 621-7615, Fax: (630) 285-1315, firstname.lastname@example.org, http://www.nsc.org .
United States Centers for Disease Control and Prevention (CDC), 1600 Clifton Road, Atlanta, GA, 30333, (404) 639-3534, 800-CDC-INFO (800-232-4636). TTY: (888) 232-6348, email@example.com, http://www.cdc.gov .
United States Consumer Products Safety Commission, 4330 East West Highway, Bethesda, MD, 20814, (301) 5047923; TTY(301) 595-7054, (800) 638-2772, Fax: Fax (301) 504-0124 and (301) 504-0025, http://www.cpsc.gov .
Linda Wasmer Smith
Revised by Tish Davidson, AM