Lead is a neurotoxicant that interferes with critical development processes in the central nervous system, potentially irreversibly damaging the developing brain. Any detectable blood lead levels are associated with adverse effects on IQ and other neurodevelopmental outcomes Lead alters basic nervous system functions, like calcium-modulated signaling, at very low concentrations in vitro. Lead levels often peak at the age of 2 years, the same age at which a major reduction in dendrite connections occurs, among other events crucial to development. It’s possible that lead exposure at that time interferes with a critical development process in the CNS, but what that specific process is has not been clearly identified.
Lead has important non-neurodevelopmental effects. The kidneys are common targets, and children exposed to lead are at significantly greater risk of becoming hypertensive as adults. Lead interferes with the body’s ability to use vital nutrients vitamin D and iron. Exposure has been linked to delayed growth. High exposure levels (BLLs greater than 40 µg/dL) may result in anemia, nephropathy, and encephalopathy, with potentially fatal seizures and cerebral edema at levels over 100 µg/dL. Health effects from early life exposure may not be clinically evident until later in life. Examples of latent adverse outcomes include ADHD, delayed learning and growth, lower IQ, developmental and behavioral problems, hypertension, hearing loss, and reproductive problems.