Toxicant and Disease Database
The CHE Toxicant and Disease Database is a searchable database that summarizes links between chemical contaminants and approximately 180 human diseases or conditions. Diseases and or toxicants can be viewed by utilizing the search options below. See a full description of the database and its limitations.
For questions or comments about the database, please contact Nancy Hepp through our Contact form.
Cognitive impairment (includes impaired learning, impaired memory, and decreased attention span) / mental retardation / developmental delay
Causes Grouped by strength of evidence
Cognitive impairment in children may occur as a result of exposures in utero or in early childhood during brain development. Metabolic studies have shown that infants absorb more manganese than adults. Manganese is added to infant formula. The effects of lead on I.Q. are non-linear and proportionally greater at lower concentrations. Canfield et al. found associated declines in I.Q. greatest at lifetime average blood lead concentrations less than 10 mg/dL. An estimated loss of 7.4 IQ points was calculated for lifetime average blood lead concentrations from 1 up to 10 mg/dL and a loss of 2.5 IQ points for concentrations 10-20 mg/dL