Prenatal methylmercury exposure and children: neurologic, developmental, and behavioral research.
Mercury is present in the earth's crust and is methylated by bacteria in aquatic environments to methylmercury (MeHg). It is then concentrated by the food chain so predatory fish and sea mammals have the highest levels. Thus, consuming seafood leads to exposure. MeHg readily crosses the placenta and the blood-brain barrier and is neurotoxic. The developing fetal nervous system is especially sensitive to its effects. Prenatal poisoning with high dose MeHg causes mental retardation and cerebral palsy. Lower level exposures from maternal consumption of a fish diet have not been consistently associated with adverse neurodevelopmental outcomes. However, most studies have considerable uncertainty associated with their results. Two large controlled longitudinal studies of populations consuming seafood are underway that are likely to determine if any adverse effects can be identified. No adverse associations have been found in the Seychelles, where exposure is mainly from fish consumption. In the Faroe Islands where exposure is primarily from consumption of whale meat and not fish, adverse associations have been reported. The Seychelles population consumes large amounts of marine fish containing MeHg concentrations similar to commercial fish in the United States. Current evidence does not support the hypothesis that consumption of such fish during pregnancy places the fetus at increased neurodevelopmental risk.
Myers
G J
GJ
Department of Neurology, University of Rochester School of Medicine and Dentistry, New York 14642, USA. gmyers@mailneurology.rochester.edu
Davidson
P W
PW
D002648:Child; D003071:Cognition; D002658:Developmental Disabilities / Q000139:chemically induced / Q000453:epidemiology; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis / Q000706:statistics & numerical data*; D005247:Feeding Behavior / Q000208:ethnology; D005260:Female; D005396:Fish Products / Q000032:analysis; D005506:Food Contamination / Q000032:analysis / Q000706:statistics & numerical data*; D014943:Global Health; D006801:Humans; D018811:Maternal Exposure / Q000009:adverse effects*; D008628:Mercury / Q000032:analysis / Q000633:toxicity; D008630:Mercury Poisoning / Q000453:epidemiology* / Q000503:physiopathology; D009460:Neurologic Examination / Q000706:statistics & numerical data; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D009792:Oceans and Seas; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011597:Psychomotor Performance; D018570:Risk Assessment
D008628:Mercury