Kermit or Kermette? Case Study
Questions
1. Does atrazine appear to alter male frog development at any concentration?
Yes at:
have the effect?
The lowest Concentration would be 0.01 at micrograms per tadpole.
3. The chemical DDT was banned for use in the U.S. in the 1960s. For years afterwards, however, American
manufacturers of DDT continued to export it to third world countries that had not yet banned its use. How
does this observation relate to the use of atrazine in the U.S. today?
Atrazine is being transported to the U.S same as how the U.S is transporting to the third world countries.
1. Does atrazine appear to alter male frog development at any concentration?
Yes at:
- Micrograms Per Tadpole: 0.01, 0.05, 0.11, 0.13, 0.83
- Micrograms per Liter: 0.1, 0.4, 0.8, 1, 25
have the effect?
The lowest Concentration would be 0.01 at micrograms per tadpole.
3. The chemical DDT was banned for use in the U.S. in the 1960s. For years afterwards, however, American
manufacturers of DDT continued to export it to third world countries that had not yet banned its use. How
does this observation relate to the use of atrazine in the U.S. today?
Atrazine is being transported to the U.S same as how the U.S is transporting to the third world countries.
1. A Syngenta press release quotes James Carr, head of the Texas Tech team, as saying, “We have been unable
to reproduce the low-concentration effects of atrazine on amphibians reported elsewhere in the scientific
literature.” This statement refers to Hayes’ results (Hayes, 2002, 2003). Comment on the accuracy of this
statement, and explain your reasoning.
He is accurate because Hayes used water which could have probably had atrazine already in it while Carr is using the water inside the lab.
2. Thee Hayes study (Hayes, 2003) was conducted using water samples collected from ponds and streams
in agricultural and non-agricultural regions of the Midwest. The study conducted by Carr’s group added
varying amounts of atrazine to de-chlorinated laboratory water. Which set of experimental conditions, if
either, would be more likely to lead to valid experimental results? Explain your reasoning.
I think Carr's would lead to a more valid experiment result. Due to that cleanliness of his water, the results would be a lot more clear than Hayes which was probably polluted with atrazine already.
3. Comment on the significance of the Carr data, shown above, that reports the percent of male frogs having
gonadal abnormalities at a nominal atrazine concentration of zero micrograms per liter and a nominal dose
of zero micrograms per liter.
Males with abnormalities were usually because of the higher dose of atrazine.
to reproduce the low-concentration effects of atrazine on amphibians reported elsewhere in the scientific
literature.” This statement refers to Hayes’ results (Hayes, 2002, 2003). Comment on the accuracy of this
statement, and explain your reasoning.
He is accurate because Hayes used water which could have probably had atrazine already in it while Carr is using the water inside the lab.
2. Thee Hayes study (Hayes, 2003) was conducted using water samples collected from ponds and streams
in agricultural and non-agricultural regions of the Midwest. The study conducted by Carr’s group added
varying amounts of atrazine to de-chlorinated laboratory water. Which set of experimental conditions, if
either, would be more likely to lead to valid experimental results? Explain your reasoning.
I think Carr's would lead to a more valid experiment result. Due to that cleanliness of his water, the results would be a lot more clear than Hayes which was probably polluted with atrazine already.
3. Comment on the significance of the Carr data, shown above, that reports the percent of male frogs having
gonadal abnormalities at a nominal atrazine concentration of zero micrograms per liter and a nominal dose
of zero micrograms per liter.
Males with abnormalities were usually because of the higher dose of atrazine.
1. What do the Hayes results indicate about the effect of atrazine on the testosterone concentration in the
blood of exposed male frogs?
The one with the highest concentration level was S3 and the lowest was S4.
2. What do the MSU results indicate about the effect of atrazine on the testosterone concentration in the blood
of exposed male frogs?
Controlled males were the ones that indicated a higher concentration of testosterone.
3. Consider the EPA’s observation about the presence of atrazine in the controls used in the MSU study. Could
this observation explain how Hayes and Hecker could both have accurately reported their experimental
observations?
Yes because Hayes's water contained no atrazine in it.
4. In 2003, the EPA recommended that Syngenta’s license to continue the use of atrazine in the United States
be approved. If one assumes that the data presented here are valid, what factor or combination of factors
might have led to this recommendation?
The data would have to be correct.
blood of exposed male frogs?
The one with the highest concentration level was S3 and the lowest was S4.
2. What do the MSU results indicate about the effect of atrazine on the testosterone concentration in the blood
of exposed male frogs?
Controlled males were the ones that indicated a higher concentration of testosterone.
3. Consider the EPA’s observation about the presence of atrazine in the controls used in the MSU study. Could
this observation explain how Hayes and Hecker could both have accurately reported their experimental
observations?
Yes because Hayes's water contained no atrazine in it.
4. In 2003, the EPA recommended that Syngenta’s license to continue the use of atrazine in the United States
be approved. If one assumes that the data presented here are valid, what factor or combination of factors
might have led to this recommendation?
The data would have to be correct.