What is lead poisoning?
Lead poisoning is a preventable condition that results from environmental exposure to lead. This exposure, indicated by elevated blood lead levels, can result in permanent health damage, especially among children. At very high levels, lead poisoning can be fatal.
According to the Centers for Disease Control and Prevention (CDC), more than half a million children in the United States between the ages of 1 and 5 years have blood lead levels greater than 5 micrograms per deciliter (mcg/dL). This is the reference blood lead level that the CDC currently considers to be unsafe. It should be noted that, according to the CDC, no safe blood lead level in children has been identified.
Lead is a soft, corrosion-resistant metal that is present in small quantities throughout the environment. Prior to 1978, it was a major ingredient in household paints and gasoline, used in water pipes, used to solder canned foods, and put into pesticides that were used in orchards. While these uses have been banned in the United States and lead is much more carefully controlled, it is still used in more than 100 industries and a variety of hobbies.
Small particles of lead enter the body primarily through inhalation or ingestion of lead-laden dust. From the lungs or intestinal tract, the lead travels to the bloodstream and organs throughout the body. The body then gradually moves lead from the blood and organs to the bones and teeth, where it may be stored for decades. About 94% of the lead in adults and 73% of that in children is eventually stored in the bones. To rid itself of lead, the body slowly takes it back out of the bones and excretes it in the urine and stool. Lead can also sometimes re-mobilize, moving back into the blood and organs when a bone is broken or during pregnancy. It can be passed from a mother to her unborn child and to an infant during breastfeeding. Women whose fetuses are exposed to lead may miscarry or have a premature delivery.
Lead poisoning can affect many different parts of the body. A single high dose of lead can cause severe symptoms, coma, and even death. However, it is more common for lead to build up in the body slowly as a result of repeated exposure to small amounts of lead. When this occurs, there may not be any obvious symptoms, but health problems get worse as the level of lead in the blood increases.
Lead is much more harmful to young children than adults because it can affect children's developing nerves and brains. The younger the child, the more harmful exposure to lead can be.
When a pregnant woman is exposed to lead, her child is at increased risk for growth delays and learning difficulties.
Infants and young children who are exposed to lead are at increased risk for:
- Developmental delays
- Learning difficulties
- Irritability/mood changes
- Loss of appetite
- Weight loss
- Sluggishness and fatigue
- Abdominal pain
- Hearing loss
- High blood pressure
- Abdominal pain
- Joint and/ or muscle pains
- Declines in mental function
- Pain, numbness, or tingling in the extremities
- Memory loss
- Mood disorders
- Reduced sperm count/abnormal sperm
- Miscarriage or premature birth in pregnant women
Very high levels of lead may cause vomiting, staggering walk, muscle weakness, seizures, or coma.
The degree to which a person is affected by exposure to lead depends on their age, the amount and time of exposure, and their own health and nutritional state. Those who are iron deficient or malnourished, for instance, are more vulnerable to increased lead absorption.
Housing built prior to 1978 may contain lead-based paint and lead-contaminated household dust. Soil surrounding these houses may also be contaminated with lead and be a source of exposure.
Children younger than 6 years of age are the most likely to be exposed to lead because they often put their hands in their mouth. The lead gets into their bodies by their ingesting lead dust or paint chips, inhaling dust, mouthing or chewing items that contain lead or have been contaminated by lead, and by eating contaminated food or drinking contaminated water.
Adult lead exposure is usually related to occupational or recreational (hobby) exposure. Children and spouses of those who work with lead may become exposed when lead contamination is brought home on the work clothes of the employee.
Work settings where lead exposure is possible
- Lead smelting
- Construction work
- Steel welding
- Bridge reconstruction
- Firing range instruction and cleaners
- Remodeling and refinishing
- Foundry work
- Scrap metal recycling
- Auto repair work
- Cable splicing
Hobbies where lead exposure is possible
- Casting bullets or fishing sinkers
- Remodeling a home built before 1978
- Target shooting at firing ranges
- Lead soldering
- Auto repair work
- Stained glass work
- Glazed pottery work
- Painting with artistic pigments
- Distilling liquor ("moonshine") in lead vessels
Some traditional or folk remedies, health foods, nutritional supplements, cosmetics, costume jewelry, toys, and canned foods imported from other countries may contain lead. Healthcare practitioners should consider screening people, especially children, who are immigrants, refugees, or who are adopted from other countries as they are at an increased risk for excessive lead exposure.