Effects of methylmercury exposure on fetuses

<p>　The causative agent of Minamata disease was methylmercury in contaminated waste-water produced during acetaldehyde manufacturing process at Chisso Co. Ltd. Adult patients with Minamata disease displayed main neurological symptoms reflecting specific regions of the brain damaged by methylmercury. In addition, a high incidence of cerebral palsy was observed between 1955 and 1959, when the pollution was most severe; this was attributed to fetal-type Minamata disease. The babies were normal during pregnancy and delivery. However, the mothers noticed severe developmental retardation of the mental and motor functions in infants after early childhood. The photograph of a mother taking a bath with a fetal-type patient, taken by Eugene Smith, in the film "Minamata," aired last year, is symbolic in showing the characteristics of fetal-type Minamata disease. A mother said she might be healthy because the baby had absorbed toxins from her body.</p><p>　When I started working at the National Institute for Minamata Disease, the World Health Organization published the Environmental Health Criteria 101 Methylmercury (1990), in a report which summarized the health risks of methylmercury. They recommended studying the effects of methylmercury on fetuses. I then decided to understand the effects of methylmercury on fetuses to protect them from methylmercury toxicity.</p><p>　The topics of my presentation are as follows:</p><p>1.Background of Minamata disease</p><p>2.Methylmercury transfer from mothers to infants via the placenta and breast milk</p><p>3.Methylmercury pollution in the Minamata area revealed by the concentrations of methylmercury in preserved umbilical cords</p><p>4.Decreased sex ratio of boys in Minamata </p><p>5.Distribution of neuronal degeneration in the brain at various stages of development</p><p>6.Prevention of methylmercury toxicity with selenium </p><p>7.Risks and benefits of fish consumption in pregnant women </p><p>8.Increased selenium concentration in Minamata disease</p><p></p>