Lead poisoning

Definition

Lead poisoning occurs when a person swallows, absorbs, or inhales lead in any form. The result can be damaging

to the brain, nerves, and many other parts of the body. Acute lead poisoning, which is somewhat rare, occurs when a relatively large amount of lead is taken into the body over a short period of time. Chronic lead poisoning — a common problem in children — occurs when small amounts of lead are taken in over a longer period. The Centers for Disease Control and Prevention (CDC) defines childhood lead poisoning as a whole-blood lead concentration equal to or greater than 10 micrograms/dL.

Description

Lead can damage almost every system in the human body, and it can also cause high blood pressure (hypertension ). 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. 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. According to the National Center for Environmental Health, there were about 200 deaths from lead poisoning in the United States between 1979 and 1998. Most of the deaths were among males (74%), African Americans (67%), adults over the age of 45 (76%), and Southerners (70%).

About one out of every six children in the United States has a high level of lead in the blood, according to the Agency for Toxic Substances and Disease Registry. 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 objects in their mouths, they are more likely than older children to take in lead. Pregnant women who come into contact with lead can pass it along to their fetuses.

Over 80% of American homes built before 1978 have lead-based paint in them, according to the Centers for Disease Control and Prevention (CDC). The older the home, the more likely it is to contain lead paint, and the

higher the concentration of lead in the paint is apt to be. Some homes also have lead in the water pipes or plumbing. People may have lead in the paint, dust, or soil around their homes or in their drinking water without knowing it, since lead cannot be seen, smelled, or tasted. Because lead does not break down naturally, it can continue to cause problems until it is removed.

Causes & symptoms

Before scientists knew how harmful it could be, lead 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:

• Lead-based paint. This is the most common source of exposure to large amounts of lead among preschoolers. Children may eat paint chips from older homes that have fallen into disrepair. They may also chew on painted surfaces, such as windowsills. In addition, paint may be disturbed during remodeling.
• Dust and soil. These can be contaminated with lead from old paint or past emissions of leaded gasoline. In addition, pollution from operating or abandoned industrial sites and smelters can find its way into the soil, resulting in soil contamination.
• Drinking water. Exposure may come from lead water pipes, found in many homes built before 1930. Even newer copper pipes may have lead solder. Also, some new homes have brass faucets and fittings that can leach lead.
• Jobs and hobbies. A number of activities can expose participants to lead. These include making pottery or stained glass, refinishing furniture, doing home repairs, and using indoor firing ranges. When adults take part in such activities, they may inadvertently expose children to lead residue that is on their clothing or on scrap materials.
• Food. Imported food cans often have lead solder. Lead may also be found in leaded crystal glassware and some imported ceramic or old ceramic dishes (e.g., ceramic dishes from Mexico). A 2003 study of cases of lead poisoning in pregnant women found that 70% of the patients were Hispanics, most of whom had absorbed the lead from their pottery. In addition, food may be contaminated by lead in the water or soil.
• Folk medicines. Certain folk medicines (for example, alarcon, alkohl, azarcon, bali goli, coral, ghasard, greta, liga, pay-loo-ah, and rueda) and traditional cosmetics (kohl, for example) contain large amounts of lead. Also, certain Chinese and Tibetan herbal remedies and techniques are contaminated with lead, and other heavy metals, such as mercury.
• Moonshine whiskey. Lead poisoning from drinking illegally distilled liquor is still a cause of death among adults in the southern United States.
• Gunshot wounds . Toxic amounts of lead can be absorbed from bullets or bullet fragments that remain in the body after emergency surgery.

Chronic lead poisoning

New evidence suggests that lead may be harmful to children even at low levels that were once thought to be safe, and the risk of damage rises as blood levels of lead increase. The symptoms of chronic lead poisoning take time to develop, however. Children can appear healthy despite having high levels of lead in their blood. Over time, though, problems such as the following may arise:

• learning disabilities
• hyperactivity
• mental retardation
• slowed growth
• hearing loss
• headaches

It is also known that certain genetic factors increase the harmful effects of lead poisoning in susceptible children; however, these factors are not completely understood as of 2003.

Lead poisoning is also harmful to adults, who may develop high blood pressure, digestive problems, nerve disorders, memory loss , and muscle and joint pain . In addition, it can lead to difficulties during pregnancy , as well as cause reproductive problems in both men and women.

More recently, chronic exposure to lead in the environment has been found to speed up the progression of kidney disorders in patients without diabetes.

Acute lead poisoning

Acute lead poisoning, while less common, shows up more quickly and can be fatal. In such cases, children are almost always affected. Symptoms such as the following may occur:

• severe abdominal pain
• diarrhea
• nausea and vomiting
• weakness of the limbs
• seizures
• coma

Diagnosis

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.

In 2002, the World Health Organization announced that evidence is emerging to show that even lower doses of lead than previously thought could cause neurological damage in children. A spokesperson said that virtually no level of lead was safe and that measures needed to be taken to remove lead from the environment.

Children at risk

Children with an increased risk of lead poisoning include those who:

• live in or regularly visit a house built before 1978 in which chipped or peeling paint is present, particularly poor children in sub-standard housing
• live in or regularly visit a house that was built before 1978 where remodeling is planned or underway
• have a brother or sister, housemate, or playmate who has been diagnosed with lead poisoning
• have the habit of eating dirt, or have been diagnosed with pica
• live with an adult whose job or hobby involves exposure to lead
• live near an active lead smelter, battery-recycling plant, or other industry that can create lead pollution

Adults at risk

Testing is also important for adults whose job or hobby puts them at risk for lead poisoning, including:

• glazed pottery or stained glass making
• furniture refinishing
• home renovation
• target shooting at indoor firing ranges
• battery reclamation
• precious metal refining
• radiator repair
• art restoration

Treatment

In the event of emergency poisoning, patients or parents should call a poison hotline at (800) 222-1222 or 911. 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 assess the home and identify lead sources.

If the problem is lead paint, a professional with special training should remove it. Removal of lead-based 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. 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 a professional 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.

Nutritional therapy

While changes in diet are no substitute for medical treatment, they can complement the detoxification process. The following nutritional changes are recommended:

• Increased consumption of fresh vegetables, fruits, beans, nuts, whole grains, and seeds.
• Increased consumption of soluble fibers, such as pears, apples, oatmeal, oat bran, rye flour, dried beans, guar gum, pectin, and psyllium.
• Increased consumption of sulfur-containing foods, such as eggs, garlic , and onions. Garlic has been used to reduce lead poisoning in animals.
• Taking high-potency multivitamin/mineral supplements (1 tablet a day).
• Taking additional supplements of vitamin C , B-complex vitamins, iron, calcium, zinc , L-lysine, L-cysteine, and L-cysteine supplements. These vitamins, minerals, and amino acids help reduce the amount of lead that the body absorbs. Iron is especially important, since people who are deficient in this nutrient absorb more lead. Thiamine , a B-complex vitamin, has been used to treat lead poisoning in animals.
• A 2002 report stated that eating tofu may lower lead levels in the blood since it is rich in calcium.
• Using a filter to prevent lead contamination in the water. Drinking lots of water (at least eight glasses per day) to help the body excrete the toxin.
• Committing to a three-day fasting at the end of every season. Fasting is the oldest method of detoxification. During fasting, patients should take supplements and drink four glasses of juice a day to assist the cleansing process and to prevent exhaustion.

Herbal therapy

Milk thistle (Silybum mariannum ) protects the liver and assists in the detoxification process by increasing glutathione supply in the liver. Glutathione is the enzyme primarily involved in the detoxification of toxic heavy metals including lead.

Homeopathy

Homeopathic medicines can be administered once the source is removed, to help correct any imbalances brought on by lead toxicity.

Allopathic treatment

In 2002, the American Association of Poison Control Centers launched a nationwide toll-free hotline for prevention and treatment of poisonings. The number is (800) 222-1222. In the case of any suspected poisoning emergency, they can be contacted 24 hours a day.

Chelation therapy

If blood levels of lead are high enough, the doctor may also prescribe chelation therapy . This refers to treatment with chemicals that bind to the lead and help the body pass it in urine at a faster rate. There are four chemical agents that may be used for this purpose, either alone or in combination. Edetate calcium disodium (EDTA calcium) and dimercaprol (BAL) are given through an intra-venous line or in shots, while succimer (Chemet) or DMSA, and penicillamine (Cuprimine, Depen) are taken by mouth. (Although many doctors prescribe penicillamine for lead poisoning, this use of the drug has not been approved by the Food and Drug Administration.)

Expected results

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.

Prevention

Many cases of lead poisoning can be prevented. These steps can help:

• Keep the areas where children play as clean and dustfree as possible.
• Wash pacifiers and bottles when they fall to the floor, and wash stuffed animals and toys often.
• Make sure children wash their hands before meals and at bedtime.
• Mop floors and wipe windowsills and other chewable surfaces, such as cribs, twice a week with 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.
• Plant grass or another ground cover in soil that is likely to be contaminated, such as soil around a home built before 1960 or located near a major highway.
• Have household tap water tested to find out if it contains lead.
• Use only water from the cold-water tap for drinking, cooking, and making baby formula, since hot water is likely to contain higher levels of lead.
• If the cold water has not been used for six hours or more, run it for several seconds, until it becomes as cold as it will get, before using it for drinking or cooking. The more time water has been sitting in the pipes, the more lead it may contain.
• 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.
• Arrange for the house to be inspected for lead. Many state health departments will do this.

Resources

BOOKS

"Heavy Metal Toxicity." In Alternative Medicine: The Definitive Guide. Tiburon, CA: Future Medicine Publishing, 1999.

Murray, Michal T., and Joseph Pizzorno. "Detoxification." In Encyclopedia of Natural Medicine. 2d ed. Rocklin, CA: Prima Publishing, 1998.

"Poisoning: Lead Poisoning." Section 19, Chapter 263 in The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.

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

Gavaghan, Helen. "Lead, Unsafe at Any Level." Bulletin of the World Health Organization (January 2002): 82.

Kaufmann, R. B., C. J. Staes, and T. D. Matte. "Deaths Related to Lead Poisoning in the United States, 1979-1998." Environmental Research 91 (February 2003): 78–84.

Lanphear, B. P., K. N. Dietrich, and O. Berger. "Prevention of Lead Toxicity in US Children." Ambulatory Pediatrics 3 (January-February 2003): 27–36.

Lidsky, T. I., and J. S. Schneider. "Lead Neurotoxicity in Children: Basic Mechanisms and Clinical Correlates." Brain 126 (January 2003) (Pt 1): 5–19.

Lin, J. L., D. T. Lin-Tan, K. H. Hsu, and C. C. Yu. "Environmental Lead Exposure and Progression of Chronic Renal Diseases in Patients Without Diabetes." New England Journal of Medicine 348 (January 23, 2003): 277–286.

"National Campaign to Promote New 24/7 Poison Hotline." Medical Letter on the CDC & FDA (March 10, 2002): 12.

Shannon, M. "Severe Lead Poisoning in Pregnancy." Ambulatory Pediatrics 3 (January-February 2003): 37–39.

Tarkin, I. S., A. Hatzidakis, S. C. Hoxie, et al. "Arthroscopic Treatment of Gunshot Wounds to the Shoulder." Arthroscopy 19 (January 2003): 85–89.

"Tofu May Lower Lead Levels in Blood." Townsend Letter for Doctors and Patients (February - March 2002): 23.

ORGANIZATIONS

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

National Lead Information Center, National Safety Council. 1025 Connecticut Ave. N.W., Suite 1200, Washington, DC 20036. (800) LEAD–FYI (general information), (800) 424–LEAD (detailed information or questions). http://www.nsc.org/ehc/lead.htm.

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

OTHER

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

Rebecca J. Frey, PhD

Lead Poisoning

Definition

Lead poisoning occurs when a person swallows, absorbs, or inhales lead in any form. The result can be damaging to the brain, nerves, and many other parts of the body. Acute lead poisoning, which is somewhat rare, occurs when a relatively large amount of lead is taken into the body over a short period of time. Chronic lead poisoning—a common problem in children—occurs when small amounts of lead are taken in over a longer period. The Centers for Disease Control and Prevention (CDC) defines childhood lead poisoning as a whole-blood lead concentration equal to or greater than 10 micrograms/dL.

Description

Lead can damage almost every system in the human body, and it can also cause high blood pressure (hypertension ). 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. 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. According to the National Center for Environmental Health, there were about 200 deaths from lead poisoning in the United States between 1979 and 1998. Most of the deaths were among males (74%), African Americans (67%), adults over the age of 45 (76%), and Southerners (70%).

About one out of every six children in the United States has a high level of lead in the blood, according to the Agency for Toxic Substances and Disease Registry. 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 come into contact with lead can pass it along to the fetus.

Over 80% of American homes built before 1978 have lead-based paint in them, according to the Centers for Disease Control and Prevention (CDC). The older the home, the more likely it is to contain lead paint, and the higher the concentration of lead in the paint is apt to be. Some homes also have lead in the water pipes or plumbing. People may have lead in the paint, dust, or soil around their homes or in their drinking water without knowing it, since lead can't be seen, smelled, or tasted. Because lead doesn't break down naturally, it can continue to cause problems until it is removed.

Causes and symptoms

Before scientists knew how harmful it could be, lead 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:

• Lead-based paint. This is the most common source of exposure to large amounts of lead among preschoolers. Children may eat paint chips from older homes that have fallen into disrepair. They may also chew on painted surfaces such as windowsills. In addition, paint may be disturbed during remodeling.
• Dust and soil. These can be contaminated with lead from old paint or past emissions of leaded gasoline. In addition, pollution from operating or abandoned industrial sites and smelters can find its way into the soil, resulting in soil contamination.

• Drinking water. Exposure may come from lead water pipes, found in many homes built before 1930. Even newer copper pipes may have lead solder. Also, some new homes have brass faucets and fittings that can leach lead.
• Jobs and hobbies. A number of activities can expose participants to lead. These include making pottery or stained glass, refinishing furniture, doing home repairs, and using indoor firing ranges. When adults take part in such activities, they may inadvertently expose children to lead residue that is on their clothing or on scrap materials.
• Food. Imported food cans often have lead solder. Lead may also be found in leaded crystal glassware and some imported ceramic or old ceramic dishes (e.g., ceramic dishes from Mexico). A 2003 study of cases of lead poisoning in pregnant women found that 70% of the patients were Hispanics, most of whom had absorbed the lead from their pottery. In addition, food may be contaminated by lead in the water or soil.
• Folk medicines. Certain folk medicines (for example, alarcon, alkohl, azarcon, bali goli, coral, ghasard, greta, liga, pay-loo-ah, and rueda) and traditional cosmetics (kohl, for example) contain large amounts of lead.
• Moonshine whiskey. Lead poisoning from drinking illegally distilled liquor is still a cause of death among adults in the southern United States.
• Gunshot wounds. Toxic amounts of lead can be absorbed from bullets or bullet fragments that remain in the body after emergency surgery.

Chronic lead poisoning

New evidence suggests that lead may be harmful to children even at low levels that were once thought to be safe, and the risk of damage rises as blood levels of lead increase. The symptoms of chronic lead poisoning take time to develop, however. Children can appear healthy despite having high levels of lead in their blood. Over time, though, problems such as the following may arise:

• learning disabilities
• hyperactivity
• mental retardation
• slowed growth
• hearing loss
• headaches

It is also known that certain genetic factors increase the harmful effects of lead poisoning in susceptible children; however, these factors are not completely understood as of 2003.

Lead poisoning is also harmful to adults, in whom it can cause high blood pressure, digestive problems, nerve disorders, memory loss, and muscle and joint pain. In addition, it can lead to difficulties during pregnancy, as well as cause reproductive problems in both men and women.

More recently, chronic exposure to lead in the environment has been found to speed up the progression of kidney disorders in patients without diabetes.

Acute lead poisoning

Acute lead poisoning, while less common, shows up more quickly and can be fatal. Symptoms such as the following may occur:

• severe abdominal pain
• diarrhea
• nausea and vomiting
• weakness of the limbs
• seizures
• coma

Diagnosis

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.

Children at risk

Children with an increased risk of lead poisoning include those who:

• Live in or regularly visit a house built before 1978 in which chipped or peeling paint is present.
• Live in or regularly visit a house that was built before 1978 where remodeling is planned or underway.

• Have a brother or sister, housemate, or playmate who has been diagnosed with lead poisoning.
• Have the habit of eating dirt, or have been diagnosed with pica.
• Live with an adult whose job or hobby involves exposure to lead.
• Live near an active lead smelter, battery-recycling plant, or other industry that can create lead pollution.

Adults at risk

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:

• glazed pottery or stained glass making
• furniture refinishing
• home renovation
• target shooting at indoor firing ranges
• battery reclamation
• precious metal refining
• radiator repair
• art restoration

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 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. 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.

Chelation therapy

If blood levels of lead are high enough, the doctor may also prescribe chelation therapy. This refers to treatment with chemicals that bind to the lead and help the body pass it in urine at a faster rate. There are four chemical agents that may be used for this purpose, either alone or in combination. Edetate calcium disodium (EDTA calcium) and dimercaprol (BAL) are given through an intravenous line or in shots, while succimer (Chemet) and penicillamine (Cuprimine, Depen) are taken by mouth. (Although many doctors prescribe penicillamine for lead poisoning, this use of the drug has not been approved by the Food and Drug Administration.)

Alternative treatment

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. However, their usefulness in humans for this purpose has not been proved. Nutritional, botanical, and homeopathic medicines can be administered once the source is removed, to help correct any imbalances brought on by lead toxicity.

Prognosis

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.

KEY TERMS

Chelation therapy— Treatment with chemicals that bind to a poisonous metal and help the body pass it in urine at a faster rate.

Dimercaprol (BAL)— A chemical agent used to remove excess lead from the body.

Edetate calcium disodium (EDTA calcium)— A chemical agent used to remove excess lead from the body.

Penicillamine (Cuprimine, Depen)— A drug used to treat medical problems (such as excess copper in the body and rheumatoid arthritis) and to prevent kidney stones. It is also sometimes prescribed to remove excess lead from the body.

Pica— An abnormal appetite or craving for nonfood items, often such substances as chalk, clay, dirt, laundry starch, or charcoal.

Succimer (Chemet)— A drug used to remove excess lead from the body.

Prevention

Many cases of lead poisoning can be prevented. These steps can help:

• Keep the areas where children play as clean and dust-free as possible.
• Wash pacifiers and bottles when they fall to the floor, and wash stuffed animals and toys often.
• Make sure children wash their hands before meals and at bedtime.
• Mop floors and wipe windowsills and other chewable surfaces, such as cribs, twice a week with 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.

• Plant grass or another ground cover in soil that is likely to be contaminated, such as soil around a home built before 1960 or located near a major highway.
• Have household tap water tested to find out if it contains lead.
• Use only water from the cold-water tap for drinking, cooking, and making baby formula, since hot water is likely to contain higher levels of lead.
• If the cold water hasn't been used for six hours or more, run it for several seconds, until it becomes as cold as it will get, before using it for drinking or cooking. The more time water has been sitting in the pipes, the more lead it may contain.
• 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.

Resources

BOOKS

Beers, Mark H., MD, and Robert Berkow, MD., editors. "Poisoning: Lead Poisoning." In The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck Research Laboratories, 2004.

PERIODICALS

Gavaghan, Helen. "Lead, Unsafe at Any Level." Bulletin of the World Health Organization January 2002: 82.

Kaufmann, R. B., C. J. Staes, and T. D. Matte. "Deaths Related to Lead Poisoning in the United States, 1979–1998." Environmental Research 91 (February 2003): 78-84.

Lanphear, B. P., K. N. Dietrich, and O. Berger. "Prevention of Lead Toxicity in US Children." Ambulatory Pediatrics 3 (January-February 2003): 27-36.

Lidsky, T. I., and J. S. Schneider. "Lead Neurotoxicity in Children: Basic Mechanisms and Clinical Correlates." Brain 126, Part 1 (January 2003): 5-19.

Lin, J. L., D. T. Lin-Tan, K. H. Hsu, and C. C. Yu. "Environmental Lead Exposure and Progression of Chronic Renal Diseases in Patients Without Diabetes." New England Journal of Medicine 348 (January 23, 2003): 277-286.

"National Campaign to Promote New 24/7 Poison Hotline." Medical Letter on the CDC & FDA March 10, 2002: 12.

Shannon, M. "Severe Lead Poisoning in Pregnancy." Ambulatory Pediatrics 3 (January-February 2003): 37-39.

Tarkin, I. S., A. Hatzidakis, S. C. Hoxie, et al. "Arthroscopic Treatment of Gunshot Wounds to the Shoulder." Arthroscopy 19 (January 2003): 85-89.

"Tofu May Lower Lead Levels in Blood." Townsend Letter for Doctors and Patients February-March 2002: 23.

ORGANIZATIONS

Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. (800) 311-3435, (404) 639-3311. 〈http://www.cdc.gov〉.

National Lead Information Center, National Safety Council. 1025 Connecticut Ave. N.W., Suite 1200, Washington, DC 20036. (800) 532-3394. 〈http://www.nsc.org/ehc/lead.htm〉.

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

Lead poisoning

Definition

Lead poisoning occurs when a person swallows, absorbs, or inhales lead in any form. The result can be damaging to the brain, nerves, and many other parts of the body. Acute lead poisoning, which is somewhat rare, occurs when a relatively large amount of lead is taken into the body over a short period of time. Chronic lead poisoning is a common problem in children that occurs when small amounts of lead are ingested over a longer period. The Centers for Disease Control and Prevention (CDC) defines childhood lead poisoning as a whole-blood lead concentration equal to or greater than 10 micrograms/dL.

Description

Lead can damage almost every system in the human body, and it can also cause high blood pressure (hypertension ). 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. 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.

Many children with elevated blood levels 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 and 36 months are apt to put things in their mouths, they are more likely than older children to take in lead. Pregnant women who come into contact with lead can pass it along to the fetus.

Over 80 percent of American homes built before 1978 have lead-based paint in them, according to the Centers for Disease Control and Prevention (CDC). The older the home, the more likely it is to contain lead paint, and the higher the concentration of lead in the paint is apt to be. Some homes also have lead in the water pipes or plumbing. Without knowing it, people may have lead in the paint, dust, or soil around their homes or in their drinking water, since lead cannot be seen, smelled, or tasted. Because lead does not break down naturally, it can continue to cause problems until it is removed.

Demographics

According to the Agency for Toxic Substances and Disease Registry, approximately one out of every six children in the United States has a high level of lead in the blood. According to the National Center for Environmental Health, there were about 200 deaths from lead poisoning in the United States between 1979 and 1998. Most of the deaths were among males (74%), African Americans (67%), adults over the age of 45 (76%), and Southerners (70%).

Causes and symptoms

Before scientists knew how harmful it could be, lead was widely used in paint, gasoline, water pipes, and many other products. In the early 2000s 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:

• Lead-based paint: This is the most common source of exposure to large amounts of lead among preschoolers. Children may eat paint chips from older homes that have fallen into disrepair. They may also chew on painted surfaces such as windowsills. In addition, paint may be disturbed during remodeling.
• Dust and soil: These can be contaminated with lead from old paint or past emissions of leaded gasoline. In addition, pollution from operating or abandoned industrial sites and smelters can find its way into the soil, resulting in soil contamination.
• Drinking water: Exposure may come from lead water pipes, found in many homes built before 1930. Even newer copper pipes may have lead solder. Also, some new homes have brass faucets and fittings that can leach lead.
• Jobs and hobbies: A number of activities can expose participants to lead. These include making pottery or stained glass, refinishing furniture, doing home repairs, and using indoor firing ranges. When adults take part in such activities, they may inadvertently expose children to lead residue that is on their clothing or on scrap materials.
• Food: Imported food cans often have lead solder. Lead may also be found in leaded crystal glassware and some imported ceramic or old ceramic dishes (e.g., ceramic dishes from Mexico). A 2003 study of cases of lead poisoning in pregnant women found that 70 percent of affected people were Hispanics, most of whom had absorbed the lead from their pottery. In addition, food may be contaminated by lead in the water or soil.
• Folk medicines: Certain folk medicines (for example, alarcon, alkohl, azarcon, bali goli, coral, ghasard, greta, liga, pay-loo-ah, and rueda) and traditional cosmetics (kohl, for example) contain high concentrations of lead.
• Moonshine whiskey: Lead poisoning from drinking illegally distilled liquor is still a cause of death among adults in the southern United States.
• Gunshot wounds : Toxic amounts of lead can be absorbed from bullets or bullet fragments that remain in the body after emergency surgery.

Evidence as of 2004 suggested that lead may be harmful to children even at low levels that were once thought to be safe, and the risk of damage rises as blood levels of lead increase. The symptoms of chronic lead poisoning take time to develop, however. Children can appear healthy despite having high levels of lead in their blood. Over time, though, problems such as the following may arise:

• learning disabilities
• hyperactivity
• mental retardation
• slowed growth
• hearing loss
• headaches

It is also known that certain genetic factors increase the harmful effects of lead poisoning in susceptible children; however, these factors are not completely understood.

Lead poisoning is also harmful to adults, in whom it can cause high blood pressure, digestive problems, nerve disorders, memory loss, and muscle and joint pain . In addition, it can lead to difficulties during pregnancy, as well as cause reproductive problems in both men and women.

In the early 2000s, chronic exposure to lead in the environment has been found to speed up the progression of kidney disorders in people without diabetes.

Acute lead poisoning

Acute lead poisoning, while less common, shows up more quickly and can be fatal. Symptoms such as the following may occur:

• severe abdominal pain
• diarrhea
• nausea and vomiting
• weakness of the limbs
• seizures
• coma

When to call the doctor

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.

Diagnosis

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. Based on 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.

Children at risk

Children with an increased risk of lead poisoning include those for whom the following is true:

• 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 underway.
• They have a brother or sister, housemate, or playmate who has been diagnosed with lead poisoning.
• They have the habit of eating dirt or have been diagnosed with pica.
• They live with an adult whose job or hobby involves exposure to lead.
• They live near an active lead smelter, battery-recycling plant, or other industry that can create lead pollution.

Adults at risk

Testing is also important for adults whose job or hobby puts them at risk for lead poisoning. This need applies to people who take part in the following activities:

• glazed pottery or stained glass production
• furniture refinishing
• home renovation
• target shooting at indoor firing ranges
• battery reclamation
• precious metal refining
• radiator repair
• art restoration

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 that parents and guardians need to find and remove 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. 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 people with gunshot injuries.

If blood levels of lead are high enough, the doctor may also prescribe chelation therapy. This refers to treatment with chemicals that bind to the lead and help the body pass it in urine at a faster rate. There are four chemical agents that may be used for this purpose, either alone or in combination. Edetate calcium disodium (EDTA calcium) and dimercaprol (BAL) are given through an intravenous line or in shots, while succimer (Chemet) and penicillamine (Cuprimine, Depen) are taken by mouth. (Although many doctors prescribe penicillamine for lead poisoning, this use of the drug has not been approved by the Food and Drug Administration.)

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. However, their usefulness in humans for this purpose has not as of 2004 been demonstrated. Nutritional, botanical, and homeopathic medicines can be administered once the source is removed to help correct any imbalances brought on by lead toxicity.

Prognosis

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.

Prevention

Many cases of lead poisoning can be prevented. The following steps can help:

KEY TERMS

Chelation therapy —A treatment using chelating agents, compounds that surround and bind to target substances allowing them to be excreted from the body.

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

Edetate calcium disodium —A chemical chelating agent used to remove excess lead from the body.

Penicillamine (Cuprimine, Depen) —A drug used to treat medical problems (such as excess copper in the body and rheumatoid arthritis) and to prevent kidney stones. It is also sometimes prescribed to remove excess lead from the body.

Pica —A desire that sometimes arises in pregnancy to eat nonfood substances, such as dirt or clay.

Succimer —A chelating agent that is used to remove excess lead from the body. Sold under the trade name Chemet.

• Keep the areas where children play as clean and dust-free as possible.
• Wash pacifiers and bottles when they fall to the floor and wash stuffed animals and toys often.
• Make sure children wash their hands before meals and at bedtime.
• Mop floors and wipe windowsills and other chewable surfaces, such as cribs, twice a week with 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.
• Plant grass or another ground cover in soil that is likely to be contaminated, such as soil around a home built before 1960 or located near a major highway.
• Have household tap water tested to find out if it contains lead.
• Use only water from the cold-water tap for drinking, cooking, and making baby formula, since hot water is likely to contain higher levels of lead.
• If the cold water has not been used for six hours or more, run it for several seconds, until it becomes as cold as it will get, before using it for drinking or cooking. The more time water has been sitting in the pipes, the more lead it may contain.
• Do not store food in open cans, especially imported cans.
• Do not store or serve food in pottery meant for decorative use.
• People who work with lead in a job or hobby should change their clothes before they go home.

Nutritional concerns

Avoid preparing or serving food in containers that have lead in their glazing. Do not consume homemade liquor that has been distilled.

Parental concerns

Lead tastes sweet. Parents living in homes built prior to 1978 should be vigilant regarding removing all flaking or peeling paint. Simply re-painting such surfaces will not resolve the problem. Parents must monitor the environments in which their children play and the objects that go into their children's mouths. Cleanliness is a must if old paint is in a child's environment. Removal (stripping paint to bare metal or bare wood) of lead is the best way to prevent lead exposure in children.

Resources

BOOKS

Goto, Collin S. "Heavy Metal Intoxication." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman, et al. Philadelphia: Saunders, 2003, pp. 2355–7.

Gupta, S. K., et al. Emergency Toxicology: Management of Common Poisons. Boca Raton, FL: CRC Press, 2003.

Klaasen, Curtis D., and John Doull. Casarett and Doull's Toxicology: The Basic Science of Poisons, 6th ed. New York: McGraw Hill, 2001.

Markowitz, Morrie. "Lead Poisoning." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman, et al. Philadelphia: Saunders, 2003, pp. 2358–61.

PERIODICALS

Clark, S., et al. "The influence of exterior dust and soil lead on interior dust lead levels in housing that had undergone lead-based paint hazard control." Journal of Occupational and Environmental Hygiene 1, no. 5 (2004): 273–82.

Dietert, R. R., et al. "Developmental immunotoxicology of lead." Toxicology and Applied Pharmacology 198, no. 2 (2004): 86–94.

Dorea, J. G. "Mercury and lead during breast-feeding." British Journal of Nutrition 92, no. 1 (2004): 21–40. Kwong W. T., et al. "Interactions between iron deficiency and lead poisoning: epidemiology and pathogenesis." Science of the Total Environment 330, no. 1–3 (2004): 21–37.

Sandel, M., et al. "The effects of housing interventions on child health." Pediatric Annals 33, no. 7 (2004): 474–81.

Stretesky, P. B., and M. J. Lynch. "The relationship between lead and crime." Journal of Health and Social Behavior 45, no. 2 (2004): 214–29.

ORGANIZATIONS

American Academy of Clinical Toxicology. 777 East Park Drive, PO Box 8820, Harrisburg, PA 17105–8820. Web site: <www.clintox.org/index.html>.

American Academy of Family Physicians. 11400 Tomahawk Creek Parkway, Leawood, KS 66211–2672. Web site: <www.aafp.org/>.

American Academy of Pediatrics. 141 Northwest Point Boulevard, Elk Grove Village, IL 60007–1098. Web site: <www.aap.org/default.htm>.

American Association of Poison Control Centers. 3201 New Mexico Avenue NW, Washington, DC 20016. Web site: <www.aapcc.org/>.

American College of Occupational and Environmental Medicine. 55 West Seegers Road, Arlington Heights, IL 60005. Web site: <www.acoem.org/>.

WEB SITES

"CDC Childhood Lead Poisoning Prevention Program: Spotlight on Lead." Centers for Disease Control and Prevention. Available online at <www.cdc.gov/nceh/lead/lead.htm> and <www.cdc.gov/nceh/lead/factsheets/leadfcts.htm> (accessed November 11, 2004).

"Lead-based Paint Hazard Control Grant Program." U.S. Department of Housing and Urban Development. Available online at <www.hud.gov/offices/lead/> (accessed November 11, 2004).

"Lead in Paint, Dust, and Soil." U.S. Environmental Protection Agency. Available online at <www.epa.gov/lead/> (accessed November 11, 2004).

"Lead Poisoning." National Library of Medicine. Available online at <www.nlm.nih.gov/medlineplus/leadpoisoning.html> (accessed November 11, 2004).

"Occupational Lead Poisoning." American Academy of Family Physicians. Available online at <www.aafp.org/afp/980215ap/stauding.html> (accessed November 11, 2004).

L. Fleming Fallon, Jr., MD, DrPH

Lead Poisoning

Lead is an indestructible heavy metal that can accumulate and linger in the body. Although the problem of lead exposure has been reduced in the United States, minorities and disadvantaged individuals remain chronically exposed. In developing countries, occupational and environmental exposures still exist and are a serious public health problem.

Definition of Lead Poisoning

Lead poisoning, or plumbism, is defined as a toxic condition caused by the ingestion or inhalation of the metallic element lead, which is found in many places, including the air, soil, water, houses, ceramic cookware, and solder used in metal cans and pipes. Lead poisoning occurs when blood lead levels are equal to or greater than 10 μg/dl (micrograms per deciliter).

Symptoms of Lead Poisoning

Lead exposure results from either inhaling or ingesting lead. Low levels of exposure (up to 10 μg/dl) are associated with anemia , headaches, general weakness, fatigue , learning disabilities, impaired development of the nervous system , and delayed growth, while greater levels of exposure (70 μg/dl) include symptoms such as decreased appetite, vomiting, abdominal pain, constipation , and drowsiness. If blood lead levels exceed 70 μg/dl, coma, seizures, bizarre behavior, impaired muscular coordination, and even death can occur.

Populations at Risk

Lead poisoning is one of the greatest environmental threats to children. Lead absorption is five to eight times greater in children than in adults. Approximately 11 percent of ingested lead will reach the adult digestive tract, as compared to 30 to 70 percent in children. In addition, children absorb up to 50 percent of inhaled lead. Children that are at greatest risk are those living near highways and interstates, in urban and inner-city areas, or in low-income housing. While the United States government banned leaded gasoline in 1986, residual lead is still present in the soil around highways and interstates. Children that live in homes or play in playgrounds near those areas can ingest lead through dust on their hands. In developing countries where leaded gasoline is still used, children living near highways are exposed to lead through automobile and truck exhaust.

Children living in inner-city and urban areas are exposed to lead through leaded paint used in older homes (prior to 1978), as well as through the presence of pipes soldered with lead solder. Lead can leach into the water in the pipes, contributing to the blood lead levels of children (and adults) ingesting the water. The major sources of lead exposure today are household dust from paint and exterior soil. In addition, children of low socioeconomic status are at a nutritional disadavantage, for they often do not consume enough food to keep their stomachs full enough to slow absorption, and because they usually do not have enough iron and calcium in their diets.

In developing countries, both adults and children face a risk of lead poisoning due to exposure sources such as leaded gasoline, lead-based cosmetics, lead solder in food containers, ceramic cookware, folk remedies, and lead-based paint. Since adverse effects of lead poisoning are magnified in malnourished populations, it is critical that developing countries recognize the threat of unintentional lead exposure.

Sources of Lead

During the 1970s, Americans discontinued the use of leaded gasoline, and other sources of environmental lead exposure have gradually been reduced. While exposure to lead has diminished, residual amounts still remain in contaminated soil, dust, lakes, and streams.

A major source of environmental exposure for children is lead-based paint. While this type of paint is no longer manufactured in the United States, buildings constructed prior to 1978 may contain residual lead. Lead exposure occurs when lead-contaminated dust is inhaled or ingested. In addition, young children may eat contaminated paint chips or ingest contaminated paint dust while sucking their hands or fingers.

Other sources of lead exposure include ceramic cookware and lead solder. Lead contained in the glaze on ceramic cookware can leach out and enter food during the cooking process. In lead-soldered pipes, lead enters the water as it passes through or collects in the pipe. People living in older homes with lead-soldered pipes should drink bottled water or make certain that the water is allowed to run several minutes before it is ingested. Water that has sat in the pipes longer than six hours should not be consumed.

While lead solder is no longer used to seal cans in the United States, imported food remains a source of exposure. Once again, lead from the solder leaches into the food. Acidic foods and drinks, such as pickles or fruit juice, enhance the leaching process. Other exposure sources include a food coloring (lozeena ) from Iraq that is sometimes used to color rice and meat, and to which lead is sometimes added; prune juice concentrate from France and raisins from Turkey (lead-containing preservatives and pesticides are used on foods such as prunes and raisins), and duck eggs from Taiwan (lead is used in the traditional method of preserving duck eggs). In addition, a number of folk remedies from around the world, as well as imported leaded crystal, can be sources of lead exposure. Folk remedies of concern include: koo sar pills, used as a remedy for menstrual cramps in Asia; azarcon, an orange powder used for intestinal illness in Mexico; ghasard, an Indian folk remedy for babies; kandu, a red powder used to treat stomachache; farouk, a Middle Eastern teething remedy; and hai gen fen, a clamshell powder added to tea.

Nutritional Interventions

Nutritional deficiencies allow lead to accumulate in body tissues and organs. The absorption of lead is greatest when the stomach is empty; therefore, consuming regular meals is important. Unfortunately, the ability to afford three meals a day is sometimes a problem for populations at risk for lead poisoning.

In the body, calcium binds to lead and inhibits its absorption; therefore, dietary calcium interferes with the absorption of lead through the intestinal mucosa . Among high-risk populations, calcium supplements or the addition of milk and yogurt to meals and snacks is recommended.

Research has also demonstrated a link between iron deficiency and lead poisoning. Recognition of this link is important, since iron deficiency is the most common childhood nutritional problem worldwide. Iron supplementation, or consuming foods rich in iron, such as fortified cereals, prunes, beef, and calves liver, can interfere with lead accumulating in the body.

Educational Interventions

In many developed nations, information programs are available to advise homeowners of lead hazards in older homes. Programs offering proper methods of exposure reduction are important, since homeowners attempting to rid their homes of lead paint and pipes with lead solder can inadvertently increase their exposure through sanding and other activities. International groups, such as the World Health Organization, are working to increase international awareness of lead exposure issues and abatement programs. In 1998, the U.S. National Center for Environmental Health identified childhood lead poisoning as one of its five global priorities.

The most effective intervention for lead poisoning is removing all sources of lead from the environment . Since this is not possible for many high-risk populations, health care providers can provide parents and child-care workers with information on how to care for children's nails and on proper hand-washing techniques, as well as information on the dangers of consuming paint chips and/or paint dust.

Consumer-awareness campaigns relating to the potential hazards of imported cookware and dishes can also help adults and children avoid unintentional ingestion of lead. Individuals need to be aware of the potential presence of lead in products and food items from other countries, particularly those that lack environmental controls relating to lead, such as Mexico, Turkey, Pakistan, India, Indonesia, Nepal, Thailand, and many countries in the Middle East and Asia.

Prevalence of Lead Poisoning

As a result of public health initiatives, lead levels in children's blood have dropped steadily since the 1970s, but approximately 434,000 U.S. children between one and five years of age still have elevated lead levels. Lead poisoning remains a particular threat among certain racial and ethnic groups that are disproportionately affected. For example, 6 percent of white children living in older housing have elevated lead levels, while the numbers for African-American and Mexican-American children in similar housing are 22 percent and 13 percent, respectively. In developing countries, which commonly use unleaded gasoline, lead poisoning is the most significant environmental disease among children. According to the World Health Organization, fifteen to eighteen million children in the developing world have suffered permanent brain damage as a result of lead poisoning.

—Paula Kepos

Medical Treatment

Typically, persons diagnosed with blood lead levels greater than 45 μg/dl will receive chelation therapy, which uses chemical agents that bind to lead in the body and cause it to be excreted in the urine or feces. High blood lead levels are considered a medical emergency requiring immediate attention, since the chances of serious complications rise as lead accumulates in the blood.

Virginia Jones Noland

Bibliography

Alters, S., and Schiff, W. (2001). Essential Concepts for Healthy Living, 2nd ed. Boston: Jones and Bartlett.

Binns, H.; Kim, D.; and Campbell, C. (2001). "Targeted Screening for Elevated Blood Lead Levels: Populations at High Risk." Pediatrics 108:1364–1366.

Chisolm, J. J. (2001). "The Road to Primary Prevention of Lead Toxicity in Children." Pediatrics 107:581–583.

Edlin, G.; Golanty, E.; and Brown, K. M. (1999). Health and Wellness, 6th ed. Boston: Jones and Bartlett.

Ellis, M., and Kane, K. (2000). "Lightening the Lead Load in Children." American Family Physician 62:545–565.

Lynch, R.; Boatright, D.; and Moss, S. (2000). "Lead-Contaminated Imported Tamarind Candy and Children's Blood Lead Levels." Public Health Reports 115:537–543.

Nadakavukaren, A. (1990). Man and Environment: A Health Perspective, 3rd ed. Prospect Heights, IL: Waveland Press.

Sargent, J. D. (1994). "The Role of Nutrition in the Prevention of Lead Poisoning in Children." Pediatric Annals 23:636–642.

Satcher, D. (2000). "The Surgeon General on the Continuing Tragedy of Childhood Lead Poisoning." Public Health Reports 115:579–580.

Simon, J., and Hudes, E. (1999). "Relationship of Ascorbic Acid to Blood Lead Levels." Journal of the American Medical Association 281:2289–2293.

Telljohann, S.; Symons, C.; and Miller, D. (2001). Health Education: Elementary and Middle School Applications, 3rd ed. Boston: McGraw Hill.

Tong, S.; Schirnding, Y; and Prapamontol, T. (2000). "Environmental Lead Exposure: A Public Health Problem of Global Dimensions." Bulletin of the World Health Organization 78:1068–1077.

Warren, C. (2000). Brush with Death: A Social History of Lead Poisoning. Baltimore, MD: Johns Hopkins University Press.

Whitney, E., and Nunnelley, E. (1987). Understanding Nutrition, 4th ed. New York: West Publishing.

Wright, R.; Shannon, M.; Wright, R.; and Hu, H. (1999). "Association between Iron Deficiency and Low-Level Lead Poisoning in an Urban Primary-Care Clinic." American Journal of Public Health 89(7):1049–1053.

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).