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.
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
|SOURCES OF LEAD POISONING|
|Paint||Lead-based paint can be a hazard in older homes. Children eat peeling paint, chew on painted surfaces, or come in contact with it during remodeling projects.|
|Dust and soil||Contamination of soil is usually caused by paint, leaded gasoline, pollution from industrial sites, and smelters.|
|Foods||Lead can be found in imported canned foods, leaded crystal, and some ceramic dishware.|
|Activities||Activities such as pottery, stained glassmaking, and furniture refinishing can heighten exposure to lead.|
|Drinking water||Homes built before 1930 may contain lead water pipes. Newer homes may also contain copper pipes with lead solder.|
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:
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.
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
- nausea and vomiting
- weakness of the limbs
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
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.
- 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.
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.
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.
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.)
If acute lead poisoning reaches the stage of seizures and coma, there is a high risk of death. Even if the person survives, there is a good chance of permanent brain damage. The long-term effects of lower levels of lead can also be permanent and severe. However, if chronic lead poisoning is caught early, these negative effects can be limited by reducing future exposure to lead and getting proper medical treatment.
Many cases of lead poisoning can be prevented. These steps can help:
- 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.
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Rebecca J. Frey, PhD