Assignment 2: fish in your local store or restaurant: mercury intake

Fish contains beneficial nutrients such as docosahexaenoic acid (DHA) that promote healthy brain development in the fetus. However, unfortunately most fish contain mercury. This poses a dilemma for pregnant women because mercury is a toxic metal pollutant that causes neurological and other health problems. The toxicity of inorganic mercury pollution is magnified in the environment because bacteria biotransform it into highly toxic methylmercury. Children who are exposed prenatally to methylmercury are especially vulnerable to the chemical’s neurotoxic effects.

For this assignment:

• Read the prenatal fish consumption advisory issued jointly by the EPA and the Food and Drug Administration (FDA) in 2004 (available at http://water.epa.gov/scitech/swguidance/fishshellfish/outreach/advice_index.cfm). Take a special note of the advice about the types of fish. Since mercury bioaccumulates (i.e., not easily excreted from the body), larger predatory fish, which eat many fish containing small amounts of mercury, contain higher levels of mercury (e.g., shark, swordfish, king mackerel, and tilefish).
• Go to the seafood section of your local grocery store, a local fish market, or a local seafood restaurant. Determine if shark, swordfish, king mackerel, or tilefish are for sale. Examine the displays, packaging, or menu warnings about fish consumption and pregnancy and breastfeeding.
• Read the following article:

  Oken, E., Radesky, J. S., Wright, R. O., Bellinger, D. C., Amarasiriwardena,
             C. J., Kleinman, K. P., … Gillman, M. W. (2008). Maternal fish intake
             during pregnancy, blood mercury levels, and child cognition at age 3
             years in a US cohort. American Journal of Epidemiology, 167(10),
             1171–1181.

  This study was able to separate the potential nutritional benefits of fish consumption during pregnancy from the potential harmful effects of low-level mercury exposure from fish. Review the abstract and the mothers’ blood mercury levels according to the amount of fish consumed per week (top of Table 1, page 1175). The introduction to the paper summarizes the nutritional benefits from fish, e.g., as a source of DHA that many women otherwise lack in their diets. In addition, review Figure 1, which shows childhood cognitive test results for mothers who consumed more fish and for mothers with higher blood mercury levels.

• Conduct research on the Internet to learn more about Minamata disease and its origins. The population was exposed to high levels of methylmercury by consuming fish that contained very high levels of the pollutant as a result of industrial discharge into Minamata Bay. The first signs that something was wrong were that fish swam crazily, sea birds were unable to fly, and cats began dancing strangely. Congenital Minamata disease was the first transplacental toxic disorder that was scientifically established; before that time, it was believed that the placenta protected the fetus from hazardous chemicals.
• Prepare a 2-page report in a Microsoft Word document addressing the following:
  • Summarize briefly the 2004 EPA and FDA fish consumption advisory, including the advice for pregnant and nursing women and women who could become pregnant.
  • Summarize briefly the key findings of the study by Oken et al. Briefly describe the ways in which the mercury-associated adverse cognitive effects measured in the three-year-old children in the study differ from the syndrome of congenital Minamata disease.
  • Report what you found when you looked for fish consumption advisories and for shark, swordfish, king mackerel, and tilefish at your local grocery store, a local fish market, or a local seafood restaurant. Devote approximately one-third to one-half of a page to this section of your report.
  • Justify your answers to the following questions using information from the above mentioned sources and relevant information from any other reputable sources:
    • What advice about fish consumption would you give to pregnant and nursing women?
    • What would be your advice for women who could become pregnant?
    • In what way, if any, should the public health system become involved in disseminating the fish consumption advisory to women? Devote approximately two-thirds of a page to this section of your report.