The data on neurobehavioral toxicity of exposure to lead suggest that children are more sensitive, as indicated by responses at lower blood lead levels, than are adult humans, and that animals are affected at roughly the same blood lead levels as are humans. This condition can result in death or in permanent cognitive impairment, particularly in children. These blood lead levels are comparable to those at which other symptoms of lead poisoning, such as gastrointestinal symptoms, occur. Common and serious limitations of studies examining neurobehavioral effects of lead in adults include inadequate estimation of cumulative exposure and inadequate control for age and intellectual ability before exposure. However, in rodents, proximal tubular cell injury induced by lead can progress to adenocarcinomas of the kidney .The observation of lead-induced kidney tumors in rats may not be relevant to humans.
All information is taken from the Toxicology Profile for Lead.