Lead and the Nervous System
Although the incidence of lead poisoning has been reduced greatly over the last two decades, many people, especially children, are still at risk. The American Academy of Pediatrics estimates that
"...almost 1 million children in the United States have elevated levels of lead in their blood."
Lead poisoning causes serious health problems, but it can be prevented. Therefore, it is essential that everyone knows about the dangers of lead and ways to prevent lead poisoning.

What Is Lead?

Lead is a common metal found naturally in the earth. The ancient Egyptians used lead in cosmetics and the ancient Romans used it to transport drinking water. Today lead is used in many products including batteries, solder, paint, fishing weights, pottery glaze, and ammunition. Lead has also been added to gasoline to reduce engine knocking. However, in the United States and much of Europe, only "lead-free" gasoline is now available.

Where Is Lead Found?

  • Paint: in the United States, paint with lead was used in many houses built before 1978. Lead helps paint last longer and stick better to surfaces. After 1978, paint with added lead was banned for use on the inside and outside of houses. Paint dust and chips from older homes may contain lead and could be inhaled or eaten accidentally. Small children are especially at risk because they may not wash their hands before they put them in their mouths.

  • Drinking water: lead is found in many plumbing pipes and fittings and in solder used in older water systems. People may drink water contaminated by lead that has leached into the water supply. The Safe Drinking Water Act passed by the US Congress in 1986 put restrictions on the use of lead-containing materials for delivering drinking water.

  • Canned food: lead solder was used to seal canned foods in the United States until 1995. Lead solder may still be used in other countries and may contaminate canned goods imported into the United States.

  • Soil: lead dust may settle on the ground and be eaten. This dust may be from lead paint on buildings or from the exhaust of cars that used leaded gasoline.

  • Pottery with lead glaze: some dishes and cups are made with glazes that contain lead. Lead can leach out of the plate or cup and contaminate food.

  • Miniblinds: some imported vinyl miniblinds have been found to contain lead. When these miniblinds break down, they may release lead dust into the air.

How Does Lead Affect the Nervous System

Lead is toxic to many organs of the body. It is especially dangerous because it can damage the brain and peripheral nerves. These nerves connect the brain and spinal cord to the rest of the body. Lead can affect anyone, but children are especially at risk because they are still growing rapidly.

Peripheral Nerve Damage

Lead poisoning can cause peripheral nerve damage: this can cause muscle weakness and problems with the sense of touch. When researchers examine these damaged nerves, they find that the myelin insulation is often gone and the axons are destroyed. These changes prevent nerves from transmitting messages properly.

Brain Damage

Lead can cross from a mother's blood supply to her developing baby in the uterus, where it concentrates in the baby's brain, liver and bones. Babies who are exposed to lead tend to be born premature and weigh less than normal. Lead may disrupt the functioning of mitochondria in the developing brain. Because the mitochondria are important for energy production within a neuron, a change in their function may damage the cell. Lead may also affect brain function by interfering with neurotransmitter release and synapse formation.

Lead affects many different areas of the brain including the cerebral cortex, cerebellum and hippocampus. The structure of blood vessels in the brain may also be altered which can can lead to bleeding and brain swelling. In children, lead exposure has been associated with reduced IQ, learning disabilities, decreased growth, hyperactive and antisocial behavior, and impaired hearing. Lead-poisoning in adults may cause muscle and joint pain, digestion problems, memory and concentration problems, high blood pressure, headaches, and dizziness.

What Can You Do To Protect Yourself and Your Family?

  • Keep your house clean: dust, dirt and soil may contain lead. A clean house will reduce the chance that someone will swallow or breathe lead accidentally.

  • Wash your hands, especially before eating: wash your hands to remove lead so you don't swallow it.

  • Think about where you plant: don't plant a vegetable garden that has old soil near a busy road.

  • Eat healthy foods: less lead is absorbed by a person who eats a diet rich in iron and calcium. Iron-rich foods include eggs, red meat, and beans; calcium-rich foods include milk, cheese and yogurt.

  • Don't use hot water from your faucet to cook: if the plumbing in your house contains lead, more lead will leach into hot water than into cold water.

  • Use miniblinds made without lead.

  • Get a blood test: if you are concerned about being exposed to lead, get your blood tested. The Centers for Disease Control believes that blood lead levels at or above 10 ug/dL are dangerous to children.

  • Determine if your house has lead paint: you should hire a professional lead inspector or risk assessor to test the paint. These professionals will use sensitive equipment to see if the paint is contaminated with lead. You may be able to mail samples of paint chips or soil to a laboratory for analysis. If your home has lead paint, don't panic. Lead paint can be removed, but it must be done by a qualified professional. DO NOT try to remove it yourself. The National Lead Service Providers' Listing System maintains a list of qualified lead inspectors, risk assessors, abatement contractors and lead analysis laboratories.

Did you know?


Beethoven
  • The "lead" in pencils is not really lead. Rather, the part of the pencil that writes is made of graphite.

  • The chemical symbol for lead is Pb. Pb comes from the Latin word for lead, plumbum.

  • Composer Ludwig van Beethoven may have been poisoned by lead. Researchers at Argonne Research Laboratory found that a lock of Beethoven's hair had lead levels 100 times greater than normal. Scientists speculate that lead may have caused some of the mental problems (irritability, depression) Beethoven experienced during his life.

References and Further Reading on Lead:

  1. CDC Childhood Lead Poisoning Prevention Program
  2. Consumer Product Safety Commission - Lead-in-Paint Activities Reduce Consumer Exposure to Lead
  3. HUD Office of Lead Hazard Control
  4. Alliance for Healthy Homes

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