What is Lead Poisoning?

Lead poisoning is entirely preventable. However, according to the Centers for Disease Control and Prevention (CDC), nearly two million children living in the United States have enough lead in their blood to cause irreversible damage to their health.

CDC defines lead poisoning in children as blood lead levels of ten micrograms of lead per deciliter of blood (ug/dL) or higher. This is known as the "blood lead intervention level." There is no known safe level of lead in the blood.

How Lead Enters the Body

Lead enters the body either through ingestion or inhalation. Young children tend to ingest more lead than adults do in a given environment, mainly due to normal hand-to-mouth behavior. A child ingests lead by putting objects in the mouth (e.g. toys or hands) that have lead-contaminated dust or dirt on them. Children may also place their mouths on surfaces containing lead-based paint (such as window sills) or ingest lead-based paint chips or soil (especially children who exhibit pica, a pattern of eating dirt or other non-food substances). Children may ingest lead from their drinking water or inhale lead dust from deteriorating paint, clothing brought home by parents exposed to occupational lead sources, or fumes from hobbies or industries that use lead.

Health Effects of Lead Poisoning

Lead poisoning affects nearly every system in the body, and often occurs with no noticeable symptoms. The complete development of the blood-brain barrier in fetuses and very young children (up to three years of age) increases the risk of lead entering the nervous system. Low but chronic exposure can affect the developing nervous systems in subtle but persistent ways. In children, blood lead levels as low as 10 to 15 ug/dL can stunt growth rates, affect attention span, cause learning disabilities, lower IQ scores, impair hearing perception, and cause behavioral problems. In addition, fetuses exposed to elevated levels of lead can suffer from low birth weight, impaired hearing, and altered gestational age, which can lead to further complications.

In addition to damaging the nervous system, elevated blood lead levels can also affect the kidneys and reproductive system, and cause high blood pressure. Very high levels (greater than 80 ug/dL) can cause convulsions, coma, or death. Levels greater than 150 ug/dL are fatal if not treated quickly. Fortunately, exposures resulting in such high levels of lead are rare.