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April/May 2016 Teacher's Guide for
Frozen Fish Stick Blues
Table of Contents



About the Guide

Teacher’s Guide editors William Bleam, Regis Goode, Barbara Sitzman and Ronald Tempest created the Teacher’s Guide article material. E-mail: bbleam@verizon.net


Susan Cooper prepared the anticipation and reading guides.
Patrice Pages, ChemMatters editor, coordinated production and prepared the Microsoft Word and PDF versions of the Teacher’s Guide. E-mail: chemmatters@acs.org
Articles from past issues of ChemMatters can be accessed from a DVD that is available from the American Chemical Society for $42. The DVD contains the entire 30-year publication of ChemMatters issues, from February 1983 to April 2013.
The ChemMatters DVD also includes Article, Title and Keyword Indexes that covers all issues from February 1983 to April 2013.
The ChemMatters DVD can be purchased by calling 1-800-227-5558.
Purchase information can be found online at www.acs.org/chemmatters.

Student Questions


(taken from the article)

Frozen Fish Stick Blues


    1. What is the limit for mercury in fish recommended by the U.S. Food and Drug Administration (FDA)?

    2. The U.S. Environmental Protection Agency (EPA) recommends consuming a limited amount of mercury. What is that recommendation?

    3. What is a microgram?

    4. List three types of seafood that the article says are safe to eat.

    5. Explain how mercury gets into fish.

    6. What are the two reasons not to eat tuna, cited in the article?

    7. According to Figure 1, what are the three sources of mercury in the environment?

    8. Mercury(II) sulfide is formed by microbes and is small enough to pass through microbial cells. What happens to the mercury once it is inside the cell?

    9. How does the methylmercury change inside a fish?

    10. Explain how the methylmercury is carried to the brain.

    11. What type of fish are in the fish sticks in this article?

Answers to Student Questions


(taken from the article)

Frozen Fish Stick Blues


      1. What is the limit for mercury in fish recommended by the U.S. Food and Drug Administration (FDA)?

The FDA says that grocery stores should not sell fish that has more than 1 part per million of mercury.

      1. The U.S. Environmental Protection Agency (EPA) recommends consuming a limited amount of mercury. What is that recommendation?

The EPA recommends not to eat more than 0.1 microgram of mercury per day per kilogram of your body mass.

      1. What is a microgram?

A microgram is one millionth of a gram.

      1. List three types of seafood that the article says are safe to eat.

The article states that it is safer to eat shrimp, sardines and tilapia.

      1. Explain how mercury gets into fish.

Plankton ingest mercury. Plankton are eaten by small fish, which are eaten by larger fish, passing the mercury onto each other, right on up the food chain.

      1. What are the two reasons not to eat tuna, cited in the article?

Tuna contains high levels of mercury and the tuna population is decreasing because they are overfished.

      1. According to Figure 1, what are the three sources of mercury in the environment?

These three sources all release mercury into the air, according to Figure 1:

  1. Volcanic eruptions,

  2. burning of coal and

  3. mining of iron

      1. Mercury(II) sulfide is formed by microbes and is small enough to pass through microbial cells. What happens to the mercury once it is inside the cell?

Once inside the cell the mercury atoms bind to methyl groups (–CH3) to form methylmercury. The methylmercury diffuses into the water and is taken up by the plankton.

      1. How does the methylmercury change inside a fish?

Inside a fish the methylmercury has a high affinity for sulfur containing anions, especially the thiol group (-SH) on the amino acid cysteine, and forms the compound methylmercury cysteine.

      1. Explain how the methylmercury is carried to the brain.

Methylmercury cysteine looks like the amino acid methionine. Proteins that usually bind with methionine will bind with methylmercury cysteine carrying the methylmercury to the brain.

      1. What type of fish are in the fish sticks in this article?

Pollock, which is low in mercury, is the fish in the fish sticks.

Anticipation Guide


Anticipation guides help engage students by activating prior knowledge and stimulating student interest before reading. If class time permits, discuss students’ responses to each statement before reading each article. As they read, students should look for evidence supporting or refuting their initial responses.
Directions: Before reading, in the first column, write “A” or “D,” indicating your agreement or disagreement with each statement. As you read, compare your opinions with information from the article. In the space under each statement, cite information from the article that supports or refutes your original ideas.


Text

Statement




  1. Farmed fish have no mercury in them.




  1. One ten-millionth of a gram is the same as 0.1 microgram.




  1. As far as mercury is concerned, tuna are safer to eat than shrimp.




  1. Mercury gets into fish through the food chain.




  1. Elemental mercury (Hg) is more dangerous than the mercury ion (Hg2+).




  1. Mercury can get into the air through natural and human-caused events.




  1. Methylmercury is very dangerous because it binds with the sulfur in an amino acid in our bodies.




  1. Methionine is an amino acid.




  1. Methylmercury damages the brain and other organs.




  1. Pollock, the fish found in many fish sticks, has high levels of mercury.
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