Mercury prenatal

Iraq Mercury Mercury used as fungicide to treat seed grain is used in bread more than 5000 severe poisoning, 450 hospital deaths, effects on many infants exposed prenatally not documented... 

A 2004 report by the Institute of Medicine s Immunization Safety Review Committee concluded that available evidence favored rejection of a causal relation between thimerosal-containing vaccines and autism. In like manner, a recent retrospective cohort study conducted by the CDC did not support a causal association between early prenatal or postnatal exposure to mercury from thimerosal-containing vaccines and neuropsychological functioning later in childhood. 

Iron is widely used in over-the-counter vitamin preparations and is a leading cause of childhood poisoning deaths. As few as 10-12 prenatal multivitamins with iron may cause serious illness in a small child. Poisoning with other metals (lead, mercury, arsenic) is also important, especially in industry. See Chapters 33, 56, and 57 for detailed discussions of poisoning by iron and other metals. 

Human pharmacokinetic studies indicate that methylmercury has a half-life in blood and the whole body of about 50 days (CDC 2005). Hair grows at about 1 cm/month with a delay of around 20 days between current blood concentration and appearance of mercury in hair (Myers et al. 2003). Thus, postnatal maternal hair can be analyzed sequentially to evaluate timing of methylmercury exposure during pregnancy. However, the potential that this affords to document critical periods of prenatal methylmercury exposure has yet to be realized. 

Kjellstrom, T., P. Kennedy, S. Wallis, and C. Mantell. 1986. Physical and Mental Development of Children with Prenatal Exposure to Mercury from Fish. Stage 1 Preliminary Test at Age 4. Report 3080. Solna, Sweden National Swedish Environmental Protection Board. 

Myers, G.J., P.W. Davidson, C. Cox, C.F. Shamlaye, D. Palumbo, E. Cernichiari, J. Sloane-Reeves, G.E. Wilding, J. Kost, L.S. Huang, and T.W. Clarkson. 2003. Prenatal methyl mercury exposure from ocean fish consumption in the Seychelle child development study. Lancet 361(9370) 1686-1692. 

C. Cox, T.W. Clarkson, D.O. Marsh, L. Amin-Zaki, S. Tikriti, and G.G. Myers, Dose-response analysis of infants prenatally exposed to methyl mercury An application of a single compartment model to single strand hair analysis. Environ. Res. 49 318, 1989. 

The second prospective study of in utero exposure to methylmercury was initiated in the Republic of Seychelles and enrolled about 800 mother-infant pairs (Myers et al., 1995). In contrast to the Faroe Islands study, the investigation in the Seychelles did not find evidence of methylmercury-related adverse effects on the neuro-behavioural development of children through nine years of age (Myers et al., 2003). In some instances, prenatal mercury exposure was actually associated with precocious behaviour, and important developmental milestones were reached more quickly in the most highly exposed subjects. 

Kjellstrom T, Kennedy P, Wallis S, Mantell C (1986) Physical and mental development of children with prenatal exposure to mercury from fish. Stage 1. Preliminary tests at age 4. Solna, National Swedish Environmental Board (Report No. 3080). 

United States Environmental Protection Agency (U.S. EPA). Mercury update impact on fish advisories. 2001. Office of Water. Grandjean P, Weihe P, White RF, Debes F, Araki S, Yokoyama K, Murata K, Sorensen N, Dahl R, Jorgensen PJ. Cognitive deficit in 7-year old children with prenatal exposure to methylmercury. Neurotoxicol.Teratol. 1997 19 417-28. 

Satoh El. Occupational and environmental toxicology of mercury and its compounds. Industrial Elealth 2000 38 153-64. Grandjean P,Weihe P, White RE, Debes F Cognitive performance of children prenatally exposed to"safe levels of methylmercury. 

Myers et al. (1997) evaluated the population of the SCDS for developmental milestones similar to those determined in Iraq. As part of this ongoing study, cohort children were evaluated at 6.5, 19, 29, and 66 months of age. At 19 months care-givers were asked at what age the child walked (n=720 out of 738) and talked (n=680). Prenatal mercury exposure was determined by atomic absorption analysis of maternal hair segments corresponding to hair growth during the pregnancy. 

Myers, Gl University of Rochester Rochester, NY Child development following prenatal methyl mercury exposure via fish diet. NIEHS... 

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