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NEURODEVELOPMENTAL EFFECTS OF ENVIRONMENTAL EXPOSURES
Citation:
Selevan, S G., P Mendola, AND D. Rice. NEURODEVELOPMENTAL EFFECTS OF ENVIRONMENTAL EXPOSURES. Presented at International Society for Environmental Epidemiology Annual Meeting, Garmisch, Germany, September 2-5, 2001.
Description:
Neurodevelopmental Effects of Environmental Exposures
Sherry G. Selevan, Pauline Mendola, Deborah C. Rice (US EPA, Washington,
DC)
The nervous system starts development early in gestation and continues to develop through adolescence. Thus, critical windows of vulnerability occur both pre- and postnatally. The nervous system is relatively unique in that different parts are responsible for different functional domains, and these develop at different times (e.g., motor control, sensory, intelligence and attention). In addition, the many different cell types in the brain have different windows of vulnerability and different sensitivities to environmental agents. Many chemicals have been found to have neurotoxic effects either in human or laboratory animal studies. This discussion will focus on two environmental agents (lead and methyl mercury), each with an extensive data base, to illustrate different spectra of neurobehavioral effects from early life exposures. With high level exposure, methyl mercury has been associated with cerebral palsy and visual and auditory deficits in children of exposed mothers. With lower level exposures, the effects in children have been more subtle cognitive deficits. Data demonstrate that methyl mercury can lead to exacerbation of neuropsychological decline with aging. Lead at high doses has resulted in encephalopathy and convulsions with perinatal and childhood exposure. Lower exposures have been associated with impairment in intellectual function and attention. While the declines in IQ have been small, they carry with them important economic and societal costs. Recent data have associated lead with violent behavior. This area is one great importance with the recognition of long-term, irreversible effects of developmental exposures.
This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.