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).