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Mercury Exposure and Child Development Outcomes

CITATION:  Davidson, P. W., Myers, G. J., & Weiss, B. (2004).  Mercury Exposure and Child Development Outcomes. Pediatrics, 113(4), 1023-1030.

Mercury is ubiquitous in the global environment, ensuring universal exposure. Some forms of mercury are especially neurotoxic, including clinical signs at high doses. However, typical human exposures occur at low to moderate doses. Only limited data about neurotoxicity at low doses are available, and scientists differ in their interpretation. Dose-response data on neurodevelopment are particularly limited. Despite or perhaps because of the lack of sufficient or consistent scientific data, public concern about a link between mercury exposure and developmental disabilities has been rising. After reviewing the data, the US Environmental Protection Agency proposed a reference dose (an estimate of a daily dose that is likely to be without a risk of adverse effects over a lifetime) for methyl mercury that is substantially lower than previous guidelines from the World Health Organization, the US Agency for Toxic Substances and Disease Registry, and the US Food and Drug Administration. Some questions have been raised about the Environmental Protection Agency's guidelines, but the issue remains unresolved. Meanwhile, consumer groups have raised questions about the potential link between mercury exposure and autism spectrum disorders as well as other adverse neurodevelopmental outcomes. This hypothesis has prompted some parents to seek regulatory, legal, or medical remedies in the absence of firm evidence. This article reviews what is known about mercury neurotoxicity and neurodevelopmental risk. Our intent is to focus the debate about mercury on 1) additional research that should be sought and 2) defining the principal issues that public policy makers face. Pediatrics 2004;113:1023-1029; mercury, developmental neurotoxicity, child neurocognitive development.


1. EPA. Mercury Report to Congress. Washington, DC: US Environmental Protection Agency, Office of Air Quality Standards; 1997

2. Mason R, Fitzgerald W, Morgan F. The biogeochemical cycling of elemental mercury: anthropogenic influences. Geo Cosmo Act. 1994;58: 3191-3194

3. Fitzgerald W, Clarkson T. Mercury and monomethylmercury: present and future concerns. Environ Health Perspect. 1991;96:159-166

4. Goldman LR, Shannon MW, the Committee on Environmental Health Policy. Technical report: mercury in the environment: implications for pediatricians. Pediatrics. 2001;108:197-205

5. Dyall-Smith DJ, Scurry JP. Mercury pigmentation and high mercury levels from the use of a cosmetic cream. Med J Aust. 1990;153:409-415

6. Mercury poisoning associated with beauty cream-Texas, New Mexico, and California, 1995-1996. MMWR Morb Mortal Wkly Rep. 1996;45: 400-403

7. Riley DM, Newby CA, Leal-Almeraz TO, Thomas VM. Assessing elemental mercury vapor exposure from cultural and religious practices. Environ Health Perspect. 2001;l09:779-784

8. Clarkson TW, Hursli JB, Sager PR, Syversen TLM. Mercury. In: Clarkson TW, Friberg L, Nordberg GF, Sager PR, eds. Biological Monitoring of Toxic Metals. New York, NY: Plenum Press; 1988:199-246

9. Drasch G, Schupp I, Hofl H, Reinke R, Roider G. Mercury burden of human fetal and infant tissues. Eur J Pediatr. 1994;153:607-610

10. Vahter M, Akesson A, Lind B, Bjors U, Schutz A, Berglund M. Longitudinal study of methylmercury and inorganic mercury in blood and urine of pregnant and lactating women, as well as in umbilical cord blood. Environ Res. 2000;84:186-194

11. Winn DM, Brunelle JA, Selwitz RH, et al. Coronal and root caries in the dentition of adults in the United States, 1988-1991. J Dent Res. 1996;75: 642-651

12. Barregard L, Sallsten G, Jarvholm B. People with high mercury intake from their own dental amalgam fillings. Occup Environ Med. 1995;52: 124-128

13. Sallsten G, Thoren J, Barregard L, Schutz A, Skarping G. Long-term use of nicotine chewing gum and mercury exposure from dental amalgam fillings. J Dent Res. 1996;75:594-598

14. Molin M, Bergman B, Marklund SL, Schutz A, Skerfving S. Mercury, selenium, and glutathione peroxidase before and after amalgam removal in man. Acta Odontol Scand. 1990;48:189-202

15. Rice D. Evidence for delayed neurotoxicity produced by methylmercury. Neurotoxicology. 1996;17:583-596

16. World Health Organization. Methylmercury. Environmental Health Criteria. 101. Geneva, Switzerland: World Health Organization; 1990

17. Bakir F, Damluji DS, Amin-Zaki L, et al. Methylmercury poisoning in Iraq. Science. 1973;181:230-241

18. Cox C, Clarkson TW, Marsh DO, Amin-Zaki L, Tikriti S, Myers GJ. Dose-response analysis of infants prenatally exposed to methylmercury. An application of a single compartment model to single-strand hair analysis. Environ Res. 1989;31:640-649

19. Davidson P, Myers G, Cox C, et al. Effects of prenatal and postnatal methylmercury exposure from fish consumption at 66 months of age: the Seychelles Child Development Study. JAMA. 1998;280:665-676

20. Grandjean P, Weihe P, White RF, et al. Cognitive deficit in 7-year-old children with prenatal exposure to methylmercury. Neurotoxicol Teratol. 1997;19:417-428

21. Myers G, Davidson P, Cox C, et al. Prenatal methylmercury exposure from ocean fish consumption in the Seychelles child development study. Lancet. 2003;361:1686-1692

22. Clarkson TW. The toxicology of mercury. Crit Rev Clin Lab Sci. 1997;34: 369-403

23. Choi BH. The effects of methylmercury on the developing brain. Prog Nenrobiol. 1989;32:467-470

24. Lapham LW, Cernichiari E, Cox C, et al. An analysis of autopsy brain tissue from infants prenatally exposed to methylmercury. Neurotoxicology. 1995;16:689-704

25. Takizawa Y, Kitamura S. Estimation of the incidence of mercury exposure in the Minamata and Niigata areas using mathematical model from Iraqi poisoning. In: Takizawa Y, Osame M, eds. Understanding Minamata Disease: Methylmercury Poisoning in Minamata and Niigata Japan. Tokyo, Japan: Japan Public Health Association; 2001:27-32

26. Harada Y. Congenital (or fetal) Minamata disease. In: Study group of Minamata Disease, eds. Minamata Disease. Kumamoto, Japan: Kumamoto University; 1968:93-118

27. Marsh D. Organic mercury: clinical and neurotoxicological aspects. In: deWollf FA, ed. Handbook of Clinical Neurology. Amsterdam, The Netherlands: Elsevier Science; 1994:419-429

28. Cernichiari E, Toribara TY, Liang L, et al. The biological monitoring of mercury in the Seychelles study. Neurotoxicology. 1995;16:613-628

29. Marsh D, Turner M, Smith J, Allen P, Richdale N. Fetal methylmercury study in a Peruvian fish-eating population. Neurotoxicology. 1995;16: 717-726

30. McKeown-Eyssen G, Reudy J, Neims A. Methylmercury exposures in Northern Quebec, II: neurologic findings in children. Am J Epidemiol. 1983;118:470-479

31. Kjellstrom T, Kennedy P, Wallis S, et al. Physical and Mental Development of Children With Prenatal Exposure to Mercury From Fish. Stage II: Interviews and Psychological Tests at Age 6. Solna, Sweden: National Swedish Environmental Protection Board; 1989 (Report 3642)

32. Kjellstrom T, Kennedy P, Wallis S, Mantell C. Physical and Mental Development of Children With Prenatal Exposure to Mercury From Fish. Stage I: Preliminary Tests at Age 4. Solna, Sweden: National Swedish Environmental Protection Board; 1986 (Report 3080)

33. Ramirez GB, Cruz CV, Pagulayan O, Ostrea E, Dalisay C. The Tagum Study I: analysis and clinical correlates of mercury in maternal and cord blood, breast milk, meconium, and infant's hair. Pediatrics. 2000;106: 774-781

34. Grandjean P, White RF, Nielsen A, Cleary D, de Oliveira Santos EC. Methylmercury neurotoxicity in Amazonian children downstream from gold mining. Environ Health Perspect. 1999;107:587-591

35. Cordier S, Garel M, Mandereau L, et al. Neurodevelopmental investigations among methylmercury-exposed children in French Guiana. Environ Res. 2002;89:1-11

36. Myers GJ, Davidson PW, Cox C, Shamlaye C, Cernichiari E, Clarkson TW. Twenty-seven years studying the human neurotoxicity of methylmercury exposure. Environ Res. 2000;83:275-285

37. Sorensen N, Murata K, Budtz-Jorgensen E, Weihe P, Grandjean P. Prenatal methylmercury exposure as a cardiovascular risk factor at seven years of age. Epidemiology. 1999;10:370-375

38. Grandjean P, Weihe P, Burse VW, et al. Neurobehavioral deficits associated with PCB in 7-year-old children prenatally exposed to seafood neurotoxicants. Neurotoxicol Teratol. 2001;23:305-317

39. Steuerwald U, Weihe P, Jorgensen P, et al. Maternal seafood diet, methylmercury exposure, and neonatal neurologic function. J Pediatr. 2000;136:599-605

40. Pless R, Richer JF. Mercury, infant neurodevelopment, and vaccination. J Pediatr. 2000;136:571-572

41. Grandjean P, Weihe P, White R. Milestone development in infants exposed to methylmercury from human milk. Neurotoxicology. 1995;16: 2-34

42. ATSDR. Toxicological Profile for Mercury: Update. Atlanta, GA: Agency for Toxic Substances and Disease Registry; 1999

43. NIEHS. Workshop on Scientific Issues Relevant to Assessment of Health Effects From Exposure to Methylmercury. Bethesda, MD: National Institutes of Health; 1998

44. National Research Council. Toxicological Effects of Methylmercury. Washington, DC: National Academy Press; 2000

45. Bernard SL, Enayati A, Binstock T, Roger H, Redwood L, McGinnis W. Autism: A Unique Type of Mercury Poisoning. Cranford, NJ: ARC Research; 2000

46. Tager-Flusberg H, Joseph R, Folstein S. Current directions in research on autism. Ment Retard Dev Dis Res Rev. 2001;7:21-29

47. Magos L. Review on the toxicity of ethylmercury, including its presence as a preservative in biological and pharmaceutical products. J Appl Toxicol. 2001;21:l-5

48. Clarkson TW. The three faces of mercury. Environ Health Perspect. 2002; 110(suppl 1):11-23

49. Institute of Medicine. Immunization Safety Review, Thimerosal-Containing Vaccines and Neurodevelopmental Disorders. Washington, DC: National Academy Press; 2001

50. Wood RW, Weiss AB, Weiss B. Hand tremor induced by industrial exposure to inorganic mercury. Arch Environ Health. 1973;26:249-252

51. Albers JW, Kallenbach LR, Fine LJ, et al. Neurological abnormalities associated with remote occupational elemental mercury exposure. Ann Neurol. 1988;24:651-659

52. Roels H, Lauwerys R, Buchet JP, Bernhard A, Barthels A. Function and psychomotor performance in workers exposed to elemental mercury. Int Arch Occup Environ Health. 1982,50:77-93

53. Echeverria D, Heyer NJ, Martin MD, Naleway CA, Woods JS, Bittner AC. Behavioral effects of low-level exposure to Hg0 among dentists. Neurotoxicol Teratol. 1995;17:161-168

54. Curtis HA, Ferguson SD, Kell RL, Samuel AH. Mercury as a health hazard. Arch Dis Child. 1987;62:293-295

55. World Health Organization. Environmental Health Criteria 118. Inorganic Mercury. Geneva, Switzerland: World Health Organization; 1991

56. Khayat A, Dencker L. Fetal uptake and distribution of metallic mercury vapor in the mouse: influence of ethanol and aminotriazole. Int J Biol Res Pregnancy. 1982;3:38-46

57. Danielsson BRG, Fredricksson A, Dahlgren L, et al. Behavioural effects of prenatal metallic mercury exposure in rats. Neurotoxicol Teratol. 1993; 15:391-396

58. Fredriksson A, Dahlgren L, Danielsson B, Eriksson P, Dencker L, Archer T. Behavioural effects of neonatal metallic mercury exposure in rats. Toxicology. 1992;74:151-160

59. Nylander M, Friberg L, Lind B. Mercury concentrations in the human brain and kidneys in relation to exposure from dental amalgam fillings. Swed Dent J. 1987;11:179-187

60. Foote RS. Mercury vapor concentrations inside buildings. Science. 1972; 177:513-514

61. Mercury exposure among residents of a building formerly used for industrial purposes-New Jersey, 1995. MMWR Morb Mortal Wkly Rep. 1996;45:422-424

62. Schwartz JG, Snider TE, Monteil MM. Toxicity of a family from vacuumed mercury. Am J Emerg Med. 1992;10:258-261

63. Gotelli CA, Astolfi E, Cox C, Cernichiari E, Clarkson TW. Early biochemical effects of an organomercury fungicide in infants: "dose makes the poison." Science. 1985;227:638-640

64. Waffarn F, Hodgman JE. Mercury vapor contamination of infant incubators: a potential hazard. Pediatrics, 1979;64:640-644

65. Agocs MM, Etzel R, Parrish RG, et al. Mercury exposure from interior latex paint. N Engl J Med. 1990;323:1096-1101

66. Yeates KO, Mortensen ME. Acute and chronic neuropsychological consequences of mercury vapor poisoning in two early adolescents. J Clin Exp Neuropsychol. 1994;16:209-222

67. Warfvinge K, Hua J, Logdberg B. Mercury distribution in cortical areas and fiber systems of the neonatal and maternal adult cerebrum after exposure of pregnant squirrel monkeys to mercury vapor. Environ Res. 1994;67:196-208

68. Newland MC, Warfvinge K, Berlin M. Behavioral consequences of in utero exposure to mercury vapor: alterations in lever-press durations and learning in squirrel monkeys. Toxicol Appl Pharmacol. 1996;139: 374-386

69. Jacobson J. Contending with contradictory data in a risk assessment context: the case of methylmercury. Neurotoxicotogy. 2001;22:667-675