lead poisoning or plumbism , intoxication of the system by organic compounds containing lead . These enter the body by respiration (of dust, fumes, or sprays) or by ingestion of food or other substances that contain lead. Lead poisoning, formerly a leading occupational hazard in industrialized countries, can be an acute episode but is usually a chronic, cumulative disease brought about by continuous exposure.

See also occupational disease .

Sources

Many of the traditional sources of lead in the United States have been minimized by a variety of federal laws, enacted from 1978 on, banning lead paint and glazes and leaded gasolines , and prohibiting the use of lead pipes in construction and the use of lead solder in food and soda cans. Workplace exposure has been regulated by laws requiring the use of respirators, dust suppressors, and proper ventilation, and lead waste disposal guidelines have been developed. Continuing sources of environmental lead include water that has passed through old lead pipes, paint in older buildings, lead improperly disposed of in public landfills, and industrial sources such as mining, smelting, and recycling processes necessary to produce lead for batteries and other products.

Young children are usually exposed by ingesting paint chips containing lead. This source is most prevalent in poor areas where old, peeling lead-containing paint and plaster in rundown housing is common. Inadequately nourished or emotionally deprived children who resort to chewing inedible things (a condition known as pica) are most susceptible.

Effects and Treatment

Acute lead poisoning can result in abdominal discomfort, nervous system damage, and encephalitis. Chronic exposure is characterized by a blue line on the gums and can lead to damage to the brain, kidneys, nervous system, and red blood cells. Even low levels can contribute to hypertension in older people or to "silent lead poisoning" in exposed children, which affects the developing brain and leads to visual-motor problems and lowered intelligence. Lower doses may be treated by altering the diet to counteract lead's effects and and cleaning the person's environment to reduce intake. Higher doses are treated with chelating agents , drugs that remove lead from the body. Symptoms recur upon subsequent exposure.

LEAD POISONING

DEFINITION

Lead poisoning occurs when a person swallows lead or breathes in its fumes. The result can be damage to the brain, nerves, and many other parts of the body. Acute lead poisoning occurs when a person takes in a large amount of lead over a short period of time. Acute lead poisoning is rare. Chronic lead poisoning occurs when small amounts of lead are taken in over a longer period. Chronic lead poisoning is a common problem among children.

DESCRIPTION

Lead can damage almost every system in the body. It can also cause hypertension (high blood pressure; see hypertension entry). Lead poisoning is especially harmful to fetuses and young children because it damages body systems that are still developing.

The seriousness of lead damage depends on two factors: the amount of lead that gets into the body and the length of time it remains there. Over the long term, lead poisoning in children can lead to learning disabilities (see learning disorders entry), behavior problems, and mental retardation (see mental retardation entry). At very high levels, lead poisoning can cause seizures, coma, and even death.

The U.S. Agency for Toxic Substances and Disease Registry estimates that one out of every six children in the United States has a high level of lead in his or her blood. One of the most common sources of lead is paint used on walls in homes. At one time, most paint contained lead. As paint gets older, it tends to peel off the walls. Because young children are inclined to put things into their mouths, they often eat these chips of paint. This problem will be less serious in the future—house paints are no longer permitted to contain lead, but old lead paint is still present in many homes.

Lead Poisoning: Words to Know

Chelation therapy:

Treatment with chemicals that bind to a poisonous metal and help the body quickly eliminate it.

Dimercaprol (BAL):

A chemical agent used in chelation therapy.

Edetate calcium disodium (EDTA calcium):

A chemical agent used in chelation therapy.

Succimer (Chemet):

A chemical agent used to remove excess lead from the body.

Another common source of lead is gasoline fumes in the air. Lead compounds were once added to gasoline to make it burn more efficiently. The lead escaped into the air when the gasoline was burned. People inhaled the lead, and it got into their bloodstreams. Today, lead compounds can no longer be used in gasoline.

Lead also gets into people's bodies through water pipes. Water pipes were once made of lead. As water passed through the pipes, it picked up small amounts of lead. When people drank that water, the lead got into their bodies. Plumbers now use copper or plastic tubing rather than lead pipes to prevent this problem.

CAUSES

Lead was once widely used in paints, gasoline, water pipes, and other products. Scientists did not realize how dangerous lead was to the human body. Since finding out how harmful lead can be, governments have banned the use of lead in most products. Some sources still pose a problem, however. These include:

• Lead-based paints. Paints in older homes are still the most common source of exposure to lead among preschool children.
• Dust and soil. Lead from gasoline fumes and from factory smokestacks eventually settles out of the air and becomes part of the soil. When people handle the soil or eat foods grown in it, they may absorb lead into their bodies.
• Drinking water. The pipes used in homes built before 1930 were usually made of lead. Drinking water in older homes may therefore contain lead.
• Jobs and hobbies. Many occupations and leisure-time activities bring people into contact with lead. Such activities include making pottery or stained glass, refinishing furniture, doing home repairs, and using indoor firing ranges for gun practice.
• Foods and containers. Foods canned in the United States contain no lead, but foods imported from other countries may be shipped in cans that are sealed with lead compounds. Also, certain kinds of glassware and ceramic dishes are made with lead compounds.
• Folk medicines. Certain types of home remedies that people have used for many years contain lead. These remedies include alarcon, azarcon, bali goli, coral, greta, liga, and pay-loo-ah.

SYMPTOMS

Scientists continue to learn more about lead poisoning. One of their newest discoveries is that very low levels of lead, once thought to be harmless, can be damaging over long periods of time. Even though a child seems healthy, he or she may have enough lead in the blood to cause chronic lead poisoning. Some symptoms of chronic lead poisoning include:

• Learning disabilities (see learning disorders entry)
• Hyperactivity (very high levels of activity)
• Mental retardation (see mental retardation entry)
• Slowed growth
• Hearing loss (see hearing loss entry)
• Headaches (see headache entry)

Lead poisoning can also affect adults. Some symptoms of the disorder among adults include high blood pressure, digestive problems, nerve disorders, memory loss, and muscle and joint pain. In addition, it can lead to difficulties during pregnancy and cause reproductive problems in both women and men.

Acute Lead Poisoning

Acute lead poisoning is less common than chronic lead poisoning. People who work around lead in their jobs, for example, are at risk for taking in large amounts of lead in a short period of time. In such cases, some of the symptoms that may develop include:

• Severe abdominal (stomach) pain
• Diarrhea
• Nausea and vomiting
• Weakness of the limbs
• Seizures
• Coma

DIAGNOSIS

A medical worker may be able to diagnose lead poisoning based on the described symptoms. The only positive test for the disorder, however, is a blood test. The U.S. Centers for Disease Control and Prevention (CDC) recommends that all children be tested for lead at twelve months of age. A blood test is important because children with lead in their blood may not show any symptoms. CDC also recommends a second blood test at the age of two years. For children known to be at risk, the CDC recommends a blood test at six months. Some states require blood tests for lead at these or other ages.

Children at Risk

Children are regarded as being at risk for lead poisoning if:

• They live in or regularly visit a house built before 1978 in which chipped or peeling paint is present.
• They live in or regularly visit a house that was built before 1978 where remodeling is planned or under way.
• They have a brother or sister, housemate, or playmate who has been diagnosed with lead poisoning.
• They live with an adult whose job or hobby involves exposure to lead.
• They live near an active lead smelter (factory), battery-recycling plant, or other industry that releases lead into the environment.

Adults at Risk

Adults whose work or hobbies expose them to lead should also have regular blood tests. These activities include:

• Working with glazed pottery or stained glass
• Furniture refinishing
• Home renovation
• Target shooting at indoor firing ranges
• Battery reclamation
• Precious metal refining
• Radiator repair
• Art restorations

TREATMENT

The first step in treating lead poisoning is to avoid further contact with 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 inspect the home and find sources of lead.

If the problem is lead paint, a professional with special training should remove it. Home owners should not try to do this job themselves. Scraping or sanding lead paint creates large amounts of dust that can poison people in the home. The dust can stay around long after the work is completed. People living in the home should leave until the cleanup has been finished by the professional.

Chelation Therapy

If blood levels of lead are high, the doctor may also prescribe chelation (pronounced kee-LAY-shun) therapy. The word "chelation" comes from the Greek word for "claw." Chemicals used in chelation therapy take hold of lead in the bloodstream, like a crab grabs an object with its claw. The lead can then be washed out of the blood.

The U.S. Food and Drug Administration (FDA) has approved three chemicals for use in chelation therapy. Edetate calcium disodium (EDTA calcium) and dimercaprol (BAL; pronounced die-muhr-KAP-rol) are usually injected with a shot. Or they can be added directly to the bloodstream with an intravenous (into the vein) line. Succimer (trade name Chemet) can be taken in pill form.

Alternative Treatment

No forms of alternative treatment have proved effective in treating lead poisoning. Increasing the amount of calcium, zinc, iron, and protein in the

diet may be of some help. They tend to reduce the amount of lead taken into the bloodstream. Some practitioners believe that nutritional, herbal, and homeopathic medicines can help the body recover from lead poisoning after the source of lead has been found and eliminated.

PROGNOSIS

If chronic lead poisoning is caught early, serious damage can be limited by reducing future exposure to lead and getting proper medical treatment. If acute lead poisoning reaches the stage of seizures and coma, there is a high risk of death. The long-term effects of lower levels of lead can also be permanent and severe.

PREVENTION

Lead poisoning can often be prevented by steps such as the following:

• Keep areas where children play as clean and dust-free as possible.
• Wash baby pacifiers and bottles when they fall on the floor. Wash toys and stuffed animals often.
• Make sure children wash their hands before meals and at bedtime.

• At least twice a week, mop floors and wipe windowsills and other surfaces on which children might chew. Use a solution of powdered dishwasher detergent in warm water.
• Plant bushes next to an older home with painted exterior walls to keep children at a distance.
• Have household tap water tested to find out if it contains lead.
• Use water only from the cold-water tap for drinking, cooking, and making baby formula. Water from the hot-water tap tends to contain higher levels of lead.
• If the cold water hasn't been used for six hours or more, run it for several seconds before using it. The longer water sits in pipes, the more lead it tends to dissolve.
• If you work with lead in your job or hobby, change your clothes before you go home.
• Do not store food in open cans, especially imported cans.
• Do not store or serve food in pottery meant for decorative use.

FOR MORE INFORMATION

Books

Centers for Disease Control and Prevention. Screening Young Children for Lead Poisoning: Guidance for State and Local Public Health Officials. Atlanta, GA: CDC, 1997.

Kessel, Irene, and John W. Graef. Getting the Lead Out: The Complete Resource on How to Prevent and Cope With Lead Poisoning. New York: Plenum Press, 1997.

Stapleton, Richard M. Lead Is a Silent Hazard. New York: Walker & Company, 1995.

Upton, Arthur, C., and Eden Graber, eds. Staying Healthy in a Risky Environment: The New York University Medical Center Family Guide. New York: Simon & Schuster, 1993.

Periodicals

Krucoff, Carol. "Lead Alert." Child (August 1996): pp. 64–65+.

Organizations

National Center for Environmental Health. Centers for Disease Control and Prevention. Mail Stop F-29, 4770 Buford Highway NE, Atlanta, GA 30341-3724. (888) 232-6789. http://www.cdc.gov/nceh/ncehhome.htm.

Office of Water Resources Center. Environmental Protection Agency. Mail Code (4100), Room 2615 East Tower Basement, 401 M St. SW, Washington, DC 20460. (800) 426-4791. http://www.epa.gov/ow/.

Web sites

"Lead Poisoning Prevention Outreach Program." National Safety Council's Environmental Health Center. [Online]. http://www.nsc.org/ehc/lead.htm (accessed on October 22, 1999).

Lead Poisoning

Timmy’s Story

What Is Lead Poisoning?

What Causes Lead Poisoning?

Who Is at High Risk?

What Are the Symptoms?

How Is Lead Poisoning Diagnosed?

How Is Lead Poisoning Treated?

Getting the Lead Out

Resources

Lead poisoning occurs when a person swallows or breathes lead, which can damage many parts of the body, especially in young children.

KEYWORDS

for searching the Internet and other reference sources

Heavy metal

Plumbism

Timmy’s Story

The year Josh turned 12, his parents bought a bigger house so that they would have a bedroom for his little brother, Timmy, who had just started to crawl. Everyone in the family was excited about the move to the house, which was in an older neighborhood with giant trees in the yards.

Josh spent many Saturday afternoons helping his dad fix up the 50-year-old house. Josh’s dad knew that chips of paint from homes this age often contain lead, which could be poisonous to Timmy if he put them in his mouth. One of his first projects, then, was to scrape off the old paint and replace it with new, lead-free paint.

A few months later, Timmy s doctor tested his blood during a routine checkup and found a high level of lead. His parents had not known that Timmy could get lead poisoning from lead dust as well as paint chips. Luckily, the problem was caught and treated early.

What Is Lead Poisoning?

Lead is a metal that has been mined for thousands of years. In the past, it was used to make many everyday items found in or near homes, such as paint, gasoline, water pipes, and food cans. When a person swallows or breathes lead, however, it can be highly poisonous. It is especially dangerous to children ages 6 years and younger. This is partly because the bodies of such young children are changing rapidly and partly because children in this age group tend to put things in their mouths.

Lead is poisonous because it interferes with some of the body’s basic activities. To some extent, the body cannot tell the difference between lead and calcium, a mineral that helps build strong bones. Like calcium, lead stays in the bloodstream for a few weeks. Then it is deposited into the bones, where it can stay for a lifetime. Even small amounts of lead can permanently harm children over time, leading to learning disabilities, behavior problems, decreased intelligence, and other damage. Large amounts of lead can cause seizures, unconsciousness, or even death.

What Causes Lead Poisoning?

There are many familiar items that are in our everyday environment that can cause lead poisoning.

Manufacturers used to put lead in paint to make it last longer and cling better to surfaces. Since 1978, the sale of lead-based paint for use in homes has been banned in the United States. It also has become illegal to paint children’s toys and household furniture with lead-based paint. However, lead-based paint is still found in more than four out of five homes built before the time of the ban. Old paint that is peeling, chipped, or chalky is a hazard. Because lead has a sweet taste, children may eat chips of lead paint. Even lead-based paint in good condition can pose a risk if it is on surfaces that children chew or that get a lot of wear and tear. Lead-based paint can also be found on old children’s toys and household furniture.

The most common way to get lead poisoning is through contact with lead in the form of dust. Lead can get into dust when old paint is scraped or sanded, or when painted surfaces bump or rub together. This dust can then settle on objects that people touch or children put into their mouths.

Oil companies used to add lead to gasoline to improve performance. This let lead particles escape into the air through car exhaust systems. In 1978, the amount of lead allowed in gasoline in the United States was cut, and cars today use lead-free gasoline. However, the soil around roads may still contain leftover lead from the old gasoline. Lead also can get into soil when the outside paint on old buildings flakes or peels.

Lead was once widely used in household plumbing. This lead can get into water that flows through the pipes. In 1986 and 1988, the use of lead in public water systems and plumbing was limited in the United States. However, the lead in old faucets, pipes, and solder used to connect pipes is still a problem. The amount of lead in water depends on the water’s temperature (warm or hot water can contain more lead), the minerals and acid it contains, how long the water sits in the pipes, and the condition of the pipes.

Lead solder was once used to seal food cans. This lead could mix with the food inside the can. In 1995, the United States banned this use of lead solder, but it still may be found in some imported cans.

Some other sources of lead are:

• Lead-glazed pottery or leaded crystal can leach lead into foods and drinks.
• Lead smelters and other industries can release lead into the air.
• Jobs that involve working with lead can get lead dust on the clothes, skin, and hair.
• Hobbies such as making pottery and refinishing furniture use lead.
• Folk medicines and homemade cosmetics sometimes contain lead.

Who Is at High Risk?

Anyone of any age can be poisoned by lead. However, the risk is greatest to young children. In the United States, about 900,000 children ages 1 to 5 years have a dangerously high level of lead in their blood. These are some situations linked to increased risk in young children:

• Living in or regularly visiting a home built before 1950.
• Living in or regularly visiting a home built before 1978 that has chipped or peeling paint or that has been remodeled recently.
• Living with an adult whose job or hobby involves contact with lead.
• Having a brother, sister, or playmate who has had lead poisoning.

What Are the Symptoms?

Lead poisoning is not easy to detect. Sometimes no symptoms occur, and at other times the symptoms look like those of other illnesses. Some of the possible early signs of lead poisoning in children are constant tiredness or overactivity, irritability, loss of appetite, weight loss, decreased attention span, trouble sleeping, and constipation.

High levels of lead can cause seizures, unconsciousness, or even death in children. However, most cases of lead poisoning involve much lower levels of lead. Over time, though, even low levels of lead may cause permanent damage. At low levels, lead can cause problems like learning disabilities, behavior problems, decreased intelligence, speech problems, decreased attention span, brain or nerve damage, poor coordination, kidney damage, decreased growth, and hearing loss.

Contact with lead is especially dangerous for children. However, it can be harmful for teenagers and adults as well. If a pregnant woman comes into contact with lead, it can raise her risk of illness during pregnancy. It can also cause problems, including brain damage or death, in her unborn baby. At high levels, lead in adults can cause problems such as infertility, high blood pressure, digestion problems, nerve disorders, memory problems, decreased attention span, and muscle and joint pain.

Lead’s Role in History

Lead lasts a long time and has a low melting temperature. In ancient Rome, wealthy families had indoor plumbing with lead pipes. (The chemical symbol for lead is Pb, from the Latin word plumbum for a lead weight. This also is the root for the word “plumber.”) The Romans also lined their outside pipes and water tanks with lead, and they made lead plates and eating utensils. Roman wine makers even sweetened sour wine by adding a syrup containing powdered lead. Modern historians have suggested that lead poisoning may explain the strange behavior of several Roman emperors, including Caligula (A.D. 12—41), who wasted a fortune on public entertainment, banished and murdered relatives, made his favorite horse a public official, and declared himself a god. The decline and fall of the Roman Empire may have been due, at least in part, to lead.

How Is Lead Poisoning Diagnosed?

Often lead poisoning has few symptoms. The only way to know whether a person has lead poisoning is to get a blood test that measures the amount of lead in the blood. Children who are not at high risk are usually tested at ages 1 and 2 years. Children who are at high risk are usually tested every 6 months between the ages of 6 months and 2 years, then once a year until age 6. A blood test can also be done at any time on anyone who has symptoms or may have had exposure to lead.

How Is Lead Poisoning Treated?

The first step in treatment is to avoid more contact with lead. This means finding and removing any sources of lead in the home. The next step is to make any needed changes in diet. Children should eat at least three meals a day, because they absorb less lead when they have food in their systems. Children also should eat plenty of foods high in iron and calcium, such as milk, cheese, fish, peanut butter, and raisins. When they do not get enough iron and calcium, their bodies mistake lead for these minerals and more lead is absorbed and deposited in their tissues.

If blood levels of lead are high enough, the doctor may prescribe a drug that chelates (KEE-lates), or binds to, lead in the body. Once lead is bound up in this way, the body can remove it through urine or bowel movements. Depending on the drug used, it may be given in a vein, by shot, or by mouth.

Getting the Lead Out

These tips can help prevent lead poisoning:

• Wash the hands often, especially after spending time outside and before eating.
• Wash the floors, windowsills, and other surfaces in the home weekly.
• Use a sponge or mop with a solution of water and all-purpose cleaner to clean up dust.
• Rinse the sponge or mop thoroughly after cleaning dirty or dusty areas.
• Keep younger children from chewing on painted surfaces, such as windowsills or cribs.
• Do not let younger children put toys and other objects with painted surfaces in their mouths.
• Have younger children play in grassy areas instead of soil, which may have lead in it.
• Wash a younger child’s bottles, pacifiers, toys, and stuffed animals often.
• Use cold tap water for drinking or cooking, because lead is more likely to leach into hot water taken from the tap.
• Eat a well-balanced diet that is low in fat and high in iron and calcium.

See also

Environmental Diseases

Resources

Book

Kessel, Irene, and John T. O’Connor. Getting the Lead Out: The Complete Resource on How to Prevent and Cope with Lead Poisoning. New York: Plenum Publishing, 1997.

Booklet

Environmental Protection Agency, Office of Pollution Prevention and Toxics. “Lead in Your Home: A Parents Reference Guide.” To order, contact the National Lead Information Center. http://www.epa.gov/lead

Organizations

Centers for Disease Control and Prevention, Lead Poisoning Prevention Branch, Mailstop F42, 4770 Buford Highway, Atlanta, GA 30341, (888) 232-6789. A federal agency that aims to prevent childhood lead poisoning. http://www.cdc.gov/nceh/pubcatns/97fsheet/leadfcts/leadfcts.htm

National Lead Information Center, 8601 Georgia Avenue, Suite 503, Silver Spring, MD 20910, (800) 424-LEAD. A federal clearinghouse for lead information. http://www.epa.gov/lead/nlic.htm

lead (led) n. a soft bluish-grey metallic element that forms several poisonous compounds. Acute lead poisoning causes abdominal pains, vomiting, diarrhoea, and sometimes encephalitis. In chronic poisoning a characteristic blue mark on the gums (l. line) is seen and the peripheral nerves are affected; there is also anaemia. Treatment is with edetate. The use of lead in paints is now strictly controlled. Symbol: Pb.