Tuna for Lunch- Case Study 1: What is in some fish and shellfish that has caused the EPA and FDA to issue the restriction for pregnant women and for young children?
Mercury
2: Why is there a restriction for pregnant women and young children, but not the rest of the population?
Mercury could affect the baby in the woman or can cause nerve damage to young children.
3: Do pregnant women have to avoid all fish? Explain your answer.
No, since the FDA states its okay for pregnant women to consume up to 12 ounces of fish per week.
4: Should Amanda have avoided the pan-seared tuna for lunch?
Yes, because the tuna could contain a high mercury level that might have been high.
5: Why is eating fish good for you? Do you want to avoid fish all together? Why or why not?
Fish provide many vitamins for your body such as omega 3 which are beneficial for the eyes. You wouldn't want to avoid fish all together since it is still apart of someones diet, and at times fish is a better choice than meat.
1: What human actions lead to increased Mercury levels in the environment?
Coal-burning power plants lead to increase mercury levels
2: How does the Mercury end in fish? DRAW a flow chart following the Mercury path.
First mercury is burned in a coal burning power plant. Second the mercury is released into the air. Third the mercury falls in the form of water and dissolves into the water. Last the fish take in the water contaminated by the mercury.
3: Where in the United States are Mercury wet deposition levels highest? What do you think explains this pattern?
Missouri, Arkansas, Tennessee, Florida since they may have the most coal-burning power plants or rain fall.
4: The EPA criterion for human health is 0.3 ug/g. Which fish species have average concentrations that exceed the EPA limits?
Largemouth and Spotted Bass contain more than 0.3 ug/g exceeding the EPA limit
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?
All fish besides channel catfish exceed the limit. Mercury level is lower than in human health because the animal might not have been able to resist mercury as much as humans.
6: Should you be concerned about mercury toxicity if you catch and eat a largemouth bass in a local lake? Why or why not?
You should be concerned if the lake is near a coal burning power plant or receives lots of rain since mercury can be transported both ways but if this not the case then no you do not have to worry.
7: In which samples were mercury concentrations the highest (fish, streams, or sediment)? Why do you think this is?
The highest concentration would be in sediments since the mercury can absorb into the ground as of if it was a stream or fish it would'nt be able to be absorbed as much since they are both moving
1: Draw a food web for Lake Washington using the species and food preferences given in Table 3. Start with phytoplankton (algae) as the base of your web and then build up the food chain.
Look after problem #2
2: Label the species in your food chain as either high (>100 ug/kg), medium (20-100 ug/kg), or low (below 20 ug/kg) mercury concentrations. Which types of animals have the highest levels of mercury? Which types of animals have the lowest? Why do you think this is?
The big fish have the highest levels of mercury. The phytoplankton have the lowest. The fish have higher levels because of biomagnification
1: Imagine you are Tara. Write a letter 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.
Dear Amanda,
After reading this I have learned that different types of fish contain different amounts of mercury. The bigger the fish contain higher amounts of mercury due to biomagnification. The mercury usually comes from coal-burning power plants since these power plants release mercury. The mercury then goes into the air/water. After that the mercury can be absorbed by fish, water or even in sediment. Larger species of fish have a higher amount of mercury since they consume all the other fish which eventually biomagnifies into a large amount. The fish with the lowest amount of mercury would be the fish at the bottom such as the cat fish.
2: Find two other samples 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.
DDT which enters biosphere from the humans spraying it in their crops and causes headache, nausea, vomiting, etc
PCBs which causes cancer in animals and could cause cancer in people
3. Distinguish between bioaccumulation and biomagnification and design a mnemonic device for the distinction
Bioaccumulation is buildup of toxic chemicals
Biomagnification is the concentration of a toxic magnifies when a larger organism eats an organism with toxic chemicals.
Distinction: Bioaccumulation->Accumulation->Accumulate->Build up
Biomagnification->Magnification->Magnify->Boost
Mercury
2: Why is there a restriction for pregnant women and young children, but not the rest of the population?
Mercury could affect the baby in the woman or can cause nerve damage to young children.
3: Do pregnant women have to avoid all fish? Explain your answer.
No, since the FDA states its okay for pregnant women to consume up to 12 ounces of fish per week.
4: Should Amanda have avoided the pan-seared tuna for lunch?
Yes, because the tuna could contain a high mercury level that might have been high.
5: Why is eating fish good for you? Do you want to avoid fish all together? Why or why not?
Fish provide many vitamins for your body such as omega 3 which are beneficial for the eyes. You wouldn't want to avoid fish all together since it is still apart of someones diet, and at times fish is a better choice than meat.
1: What human actions lead to increased Mercury levels in the environment?
Coal-burning power plants lead to increase mercury levels
2: How does the Mercury end in fish? DRAW a flow chart following the Mercury path.
First mercury is burned in a coal burning power plant. Second the mercury is released into the air. Third the mercury falls in the form of water and dissolves into the water. Last the fish take in the water contaminated by the mercury.
3: Where in the United States are Mercury wet deposition levels highest? What do you think explains this pattern?
Missouri, Arkansas, Tennessee, Florida since they may have the most coal-burning power plants or rain fall.
4: The EPA criterion for human health is 0.3 ug/g. Which fish species have average concentrations that exceed the EPA limits?
Largemouth and Spotted Bass contain more than 0.3 ug/g exceeding the EPA limit
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?
All fish besides channel catfish exceed the limit. Mercury level is lower than in human health because the animal might not have been able to resist mercury as much as humans.
6: Should you be concerned about mercury toxicity if you catch and eat a largemouth bass in a local lake? Why or why not?
You should be concerned if the lake is near a coal burning power plant or receives lots of rain since mercury can be transported both ways but if this not the case then no you do not have to worry.
7: In which samples were mercury concentrations the highest (fish, streams, or sediment)? Why do you think this is?
The highest concentration would be in sediments since the mercury can absorb into the ground as of if it was a stream or fish it would'nt be able to be absorbed as much since they are both moving
1: Draw a food web for Lake Washington using the species and food preferences given in Table 3. Start with phytoplankton (algae) as the base of your web and then build up the food chain.
Look after problem #2
2: Label the species in your food chain as either high (>100 ug/kg), medium (20-100 ug/kg), or low (below 20 ug/kg) mercury concentrations. Which types of animals have the highest levels of mercury? Which types of animals have the lowest? Why do you think this is?
The big fish have the highest levels of mercury. The phytoplankton have the lowest. The fish have higher levels because of biomagnification
1: Imagine you are Tara. Write a letter 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.
Dear Amanda,
After reading this I have learned that different types of fish contain different amounts of mercury. The bigger the fish contain higher amounts of mercury due to biomagnification. The mercury usually comes from coal-burning power plants since these power plants release mercury. The mercury then goes into the air/water. After that the mercury can be absorbed by fish, water or even in sediment. Larger species of fish have a higher amount of mercury since they consume all the other fish which eventually biomagnifies into a large amount. The fish with the lowest amount of mercury would be the fish at the bottom such as the cat fish.
2: Find two other samples 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.
DDT which enters biosphere from the humans spraying it in their crops and causes headache, nausea, vomiting, etc
PCBs which causes cancer in animals and could cause cancer in people
3. Distinguish between bioaccumulation and biomagnification and design a mnemonic device for the distinction
Bioaccumulation is buildup of toxic chemicals
Biomagnification is the concentration of a toxic magnifies when a larger organism eats an organism with toxic chemicals.
Distinction: Bioaccumulation->Accumulation->Accumulate->Build up
Biomagnification->Magnification->Magnify->Boost