Cambridge University Technological Integration in Language Teaching Discussion

Did you know that an estimated 17% of the global protein is provided by fish? In many developing countries that number is closer to 70%; the demand for fish steadily increases with human population. Not only are more people depending on fisheries for the most important source of protein, but, according to the Food & Agriculture Organization of the United Nations, the amount of fish individuals eat has also gone up from 10 kg in the 1960s to more than 19 kg in 2012 and has continued to rise. Also, according to the FAO: “The renewed focus on the so-called “blue world” comes as the share of fisheries production used by humans for food has increased from about 70 percent in the 1980s to a record high of more than 85 percent (136 million tonnes) in 2012.” If you would like to read more about this issue from FAO here are two articles: FAO article #1 (Opens in new tab)* (Links to an external site.) and FAO article #2 (Opens in new tab)* (Links to an external site.)

An increasing human population is putting stress on fisheries through overfishing; however, that is not the only way we have a negative impact to fisheries. As we burn fossil fuels to create our electricity and move ourselves and goods from place to place, we add mercury to the the atmosphere. This mercury is then washed from the atmosphere with rain and ends up in our waters. This leads to bioaccumulation by individual species in our oceans, and biomagnification as the mercury moves up the food chain.

INSTRUCTIONS:

This assignment is meant to help students understand and consider this issue.

The first step is to read the case study. Within the case study you will find embedded questions, students should pause and consider these before reading on. Once you have read completely through the case study, go back and answer the questions, a word file with the questions is provided for students.

Tuna for Lunch?
First read the “mercury_in_fish_case study” file found in Canvas for this unit. While reading you will come
across questions, pause to consider them, most of them you will answer for this assignment.
After you read the entire case study, answer the questions below.
Questions (Part II)
1. What is in some fish and shellfish that has caused the EPA and FDA to issue the restriction? (5 points)
2. Why is there a restriction for pregnant women and young children, but not the rest of the population? (10 points)
3. Do pregnant women have to avoid all fish? Explain your answer. (5 points)
4. Should Amanda have avoided the pan-seared tuna for lunch? (5 points)
Questions (Part III)
1. What human actions lead to increased mercury levels in the environment? (10 points)
2. How does the mercury end up in fish? (5 points)
3. Where in the United States are mercury wet deposition levels highest? What do you think explains this pattern? (5
points)
4. The EPA criterion for human health is 0.3 ug/g. Which fish species have average mercury concentrations that exceed
the EPA limits? (5 points)
5. The concern level for piscivorous (fish-eating) mammals is 0.1 Hg ug/g. Which fish species have average mercury
concentrations that exceed this limit? Why is the mercury level for piscivorous mammals lower than the level for human
health? (10 points)
6. Should you be concerned about mercury toxicity if you catch and eat a largemouth bass in a local lake? Why or why
not? (10 points)
7. In which samples were mercury concentrations the highest (fish, streams, or sediment)? Why do you think this is? BE
SURE to pay close attention to the units when finding this answer! (10 points)
Final Activity (based on all parts of the case study and external research)
1. Imagine you are Tara. Write a short summary to your friend Amanda explaining what you have learned about
mercury. Be sure to convey the aspects of your learning that will be most useful to Amanda. Basically this is a summary
of what you learned. (5 points)
2. Find two other examples of compounds that biomagnify. Explain how each compound and/or toxin enters the
biosphere and what impacts it has on living organisms in general and humans in particular. Remember your previous
assignments which you considered reliable sources, be sure you consult reliable sources for this answer and include the
sources in your answer. (10 points)
3. Distinguish between bioaccumulation and biomagnification. (5 points)