What Is It?
Lead, a metal used in manufacturing primarily because of its resistance to corrosion, is poisonous when inhaled or ingested by humans. It enters the bloodstream and is stored in the organs, tissues, bones and teeth. With increasing or prolonged exposure, this toxin can cause:
- Permanent damage to the central nervous system, especially the brain
- Developmental delays in children
- Behavioral changes in children
- Decreased production of red blood cells (anemia)
- Hearing problems
- Damage to the reproductive systems of men and women
- Kidney disease
- Convulsions (seizures)
The leading source of exposure is lead-based paint, which remains in about 40 percent of U.S. houses, nearly all of them built before lead paint was outlawed for residential use in 1978. The main hazard is paint dust, which enters the air when old paint is scraped, sanded or begins to flake. Undisturbed lead paint in good condition usually is not a problem.
Other ways people can ingest or inhale lead include drinking water from pipes that are made of lead or use lead solder, using ceramic dishes made with lead, playing in lead-contaminated soil, using lead in hobbies or crafts such as stained-glass work, or consuming certain home remedies containing lead.
Children face the most serious risk because their developing systems absorb more lead. Young children, especially toddlers, also play on the floor and tend to put objects in their mouths that may be covered with lead dust. If lead paint is flaking, small children sometimes eat the sweet-tasting paint chips or chew on painted surfaces.
Adults who have high lead levels in their blood usually have been exposed in the workplace. Industries with high potential exposure include construction that involves welding, cutting, blasting or other disturbances of lead-painted surfaces; smelter operations; radiator repair shops; and firing ranges. Young children can be exposed to lead from parents who work in these areas and carry lead dust home with them on their clothes and shoes.
A woman with a history of lead poisoning can pass lead on to her fetus if she becomes pregnant, even if she no longer is exposed to lead. This occurs because more than 90 percent of lead may be stored in the bones and then released into the bloodstream years later.
Since lead was banned in gasoline and residential paint, average blood-lead levels have dropped dramatically in the United States. Nevertheless, the most recent estimate from the U.S. Centers for Disease Control and Prevention, using data collected from 1999 to 2000, is that 434,000 young children still had lead levels of at least 10 micrograms per deciliter, the maximum recommended level for children. Recent studies suggest that even lower levels may be harmful.
Efforts to reduce lead exposure in the workplace aim to decrease the number of adults with elevated blood lead levels. The CDC estimated in 1994 (from data collected 1988 to 1991) that 700,000 adults had blood-lead levels of 25 micrograms per deciliter or higher. Preliminary results from more recent data (collected 1998 to 2001) suggest that this number has decreased by as much as 20 percent.
Children with blood-lead levels of 10 micrograms per deciliter to 25 micrograms per deciliter usually do not show any obvious symptoms. The damage may be subtle and tends to become evident at school age, when the child may display learning disabilities, behavioral problems or mental retardation.
The effect of blood lead on young children has been estimated as an average loss of two to three IQ points for each 10 micrograms of blood lead per deciliter. At higher exposures, children may experience:
- Decreased production of red blood cells (anemia)
- Tiredness and fatigue
- Severe abdominal pain and cramps
- Hearing problems
- Slowed growth
- Persistent vomiting
- Convulsions (seizures)
Adults with blood-lead levels of 40 micrograms per deciliter to 50 micrograms per deciliter may display some of the same symptoms, or any of the following:
- Inability to sleep (insomnia)
- Memory and concentration problems
- Kidney damage
- High blood pressure (hypertension)
- In pregnant women: stillbirths, miscarriages, premature births or problems in fetal neurological development
A doctor who suspects lead poisoning will conduct a physical examination and may inquire about symptoms, medical history, potential environmental exposure to lead, diet and (in children) any learning or behavior problems. Lead poisoning is diagnosed with a simple blood test. Blood is drawn by inserting a syringe into a vein or by pricking a finger.
Because there are often no initial symptoms, screening is the best way to identify children at risk of lead poisoning at an early stage, typically starting at age 6 months. Blood-lead screening is required at ages 1 and 2 for all children enrolled in the Medicaid program. The U.S. Centers for Disease Control and the American Academy of Pediatrics recommend that children under age 6 be tested for lead if they:
- Live in or regularly visit a house or child-care center built before 1950, or one built before 1978 that has been remodeled in the last six months
- Have a brother, sister, housemate or playmate who is being treated for lead poisoning
- Live with a parent whose job or hobby involves exposure to lead
- Live near an active smelter, battery recycling plant or other industry likely to release lead into the air
- Have been seen eating paint chips or dirt
- Have low levels of iron in the blood (anemia)
Lead levels are tested in the blood, but lead becomes concentrated in many areas of the body, especially the bones. It may take several weeks, months or years for lead to leave the body, even after there is no further exposure.
Lead poisoning can be prevented by avoiding or minimizing exposure to lead, especially by removing lead paint or containing it with frequent cleaning. Measures include the following:
- Careful and frequent cleaning alone has been shown to reduce exposure to lead substantially. Use a mop or sponge with warm water and a general, all-purpose cleaner or a cleaner made especially for lead to regularly clean floors and other surfaces. Frequently wash a child’s hands, toys and pacifiers with soap and water.
- If you have lead paint in your home, removing it may not be the best option. Improper removal of lead paint can make contamination worse by sending lead-containing dust into the air. In any case, do not try to remove or paint over it yourself. Hire a professional trained in lead-abatement techniques. Call (800) 424-LEAD (5323) for a list of contacts in your area.
- If you have lead pipes or lead solder in your plumbing, or if you have an older house and are not sure about the pipes, call your local health department or water supplier for information on getting your water tested. Meanwhile, use only cold water for drinking, cooking and for making baby formula, and run the water for 15 seconds to 30 seconds before drinking it, especially if you have not used the water from that faucet for a few hours.
- If your job involves potential lead exposure, insist that your employer comply with all federal and state laws to protect workers and to monitor their health. Follow all recommended measures (masks, protective clothing, etc.) to protect yourself. Before coming home, shower and change your clothes. Launder your work clothes separately from those of the rest of the family or from clothes you do not wear for work.
- Avoid storing food in lead crystal or lead-glazed dishes. Do not use folk remedies that contain lead, such as greta and arzacon, which are used for an upset stomach or indigestion, or pay-loo-ah, which is used for rash or fever. Do not use cosmetics that contain lead such as kohl (eyeliner).
For all cases of lead exposure, the most important treatment is to remove the source of lead. In most cases, no additional treatment is necessary. High levels of lead in the bloodstream may need to be treated by taking a drug that binds to the lead and helps the body to remove it, a process called chelation therapy. People whose blood-lead levels are less than 45 micrograms per deciliter normally are not given these drugs unless removing the source of lead failed to help.
People with blood-lead levels of 45 micrograms per deciliter to 70 micrograms per deciliter usually are treated with drugs. Immediate hospitalization and chelation therapy are needed if blood-lead levels exceed 70 micrograms per deciliter, or if there is evidence of encephalopathy, a form of brain damage whose symptoms include headaches, convulsions, delirium and persistent vomiting. Encephalopathy is a life-threatening emergency.
After treatment or removal of the environmental lead source, the doctor normally will do another blood-lead test or series of tests to monitor progress until the blood-lead level is no longer elevated. Besides recommending a nutritious diet, the doctor also may recommend iron or calcium supplements.
When To Call A Professional
If you are the parent or guardian of a child under age 6, make sure he or she visits a health professional regularly to discuss possible risks of lead poisoning and to be tested, as indicated. See the child’s doctor immediately if you notice symptoms of lead poisoning or suspect that the child has been exposed to lead.
The prognosis for children with lead poisoning depends on the amount of lead in the body, the duration of exposure, and the response to treatment. Children with brief, low-level exposures usually recover completely. Many children with low to moderate lead exposures for prolonged periods have decreased intellectual function. Even with appropriate treatment, children with high levels of blood lead can have severe, irreversible brain damage.
Diseases and Conditions Center
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.