1. Does atrazine appear to alter male frog development at any concentration?
Yes , in the first data is 0.01, 0.05, 0.11, 0.13 atrazine dose (micrograms per tadpole). and for the second data is 0.1, 0.4, 0.8, 1, 25 atrazine concentration (micrograms per liter).
2. If atrazine does affect male grog development, what is the lowest concentration and dose that appears to have the effect?
0.01 atrazine dose (micrograms per tadpole)
3. The chemical DDT was banned for use in the US in the 1960s. For years afterwards, however, American manufactures of DDT continued to export it to 3th world countries that had not yet banned its use. How does this observation relate to the use of atrazine in the US today?
they manufacturing the chemical for the other countries
1. A Syngeta 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.
I concur with his idea, because the Tyrone used maybe it already be concentrated with atrazine. The reason why higher dosages sometimes don't have any % of gonadal abnormalities because the concentration maybe affected Tyrone's result.
2. The 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 result? Explain your reasoning.
The water that he is using is de-chlorinated that might be contain other chemical and it will affects the results.
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.
They are both the same because the nominal dose may not affected the frogs.
1. What do the Hayes results indicate about the effect of atrazine on the testosterone concentration in the blood of exposed male frogs?
atrazine raised the concentration on the testosterone in the blood of exposed male frogs
2. What do the MSU results indicate about the effect of atrazine on the testosterone concentration in the blood of exposed male frogs?
0.5 and down
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 observation?
Yes, because the water that he used contained atrazine on the other side the water Tyrone using didn't have any of concentration of atrazine
4. In 2003, the EPA recommended that Syngenta's license to continue the use of atrazine in the US be approved. If 1 assumes that the data presented here are valid, what factor or combination of factors might have led to this recommendation?
It don't have any of direct evidence that have led to this recommendation.
5. Search for 2 web sites that support the continued use of atrazine and 2 web sites opposed to its continued use. Prepare an assessment of the validity of these web sites and be prepared to share your observations in class. Useful guidelines for the evaluation of the credibility of web postings may be found at the following URL: http://www.virtualchase.com/quality/checklist_print.html.
For: 1. http://www.atrazinefacts.com/growers-support-continued-atrazine-use/
-they need the popular herbicide atrazine to enhance other weed killing chemistry. Atrazine, on the market now for a half-century, has come under fire from researchers and activists who say it gets into surface water and affects fish and frogs
2.http://cornandsoybeandigest.com/crop-chemicals/farmers-speak-out-support-atrazine
-levels in raw and finished water are steadily declining. Atrazine was applied to 60% of conservation tillage and no-till corn acres.
Against: 1. http://www.savethefrogs.com/threats/pesticides/atrazine/index.html
-To allow the continued use and production of Atrazine, the EPA sets a dangerous precedent by condoning environmental destruction and implying that it is environmentally sound and ethical to dump poison on American soil and on Americans.
2. http://www.i-sis.org.uk/atrazine.php
-Atrazine is registered for use on range grasses for establishing permanent grass cover on rangelands.
Yes , in the first data is 0.01, 0.05, 0.11, 0.13 atrazine dose (micrograms per tadpole). and for the second data is 0.1, 0.4, 0.8, 1, 25 atrazine concentration (micrograms per liter).
2. If atrazine does affect male grog development, what is the lowest concentration and dose that appears to have the effect?
0.01 atrazine dose (micrograms per tadpole)
3. The chemical DDT was banned for use in the US in the 1960s. For years afterwards, however, American manufactures of DDT continued to export it to 3th world countries that had not yet banned its use. How does this observation relate to the use of atrazine in the US today?
they manufacturing the chemical for the other countries
1. A Syngeta 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.
I concur with his idea, because the Tyrone used maybe it already be concentrated with atrazine. The reason why higher dosages sometimes don't have any % of gonadal abnormalities because the concentration maybe affected Tyrone's result.
2. The 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 result? Explain your reasoning.
The water that he is using is de-chlorinated that might be contain other chemical and it will affects the results.
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.
They are both the same because the nominal dose may not affected the frogs.
1. What do the Hayes results indicate about the effect of atrazine on the testosterone concentration in the blood of exposed male frogs?
atrazine raised the concentration on the testosterone in the blood of exposed male frogs
2. What do the MSU results indicate about the effect of atrazine on the testosterone concentration in the blood of exposed male frogs?
0.5 and down
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 observation?
Yes, because the water that he used contained atrazine on the other side the water Tyrone using didn't have any of concentration of atrazine
4. In 2003, the EPA recommended that Syngenta's license to continue the use of atrazine in the US be approved. If 1 assumes that the data presented here are valid, what factor or combination of factors might have led to this recommendation?
It don't have any of direct evidence that have led to this recommendation.
5. Search for 2 web sites that support the continued use of atrazine and 2 web sites opposed to its continued use. Prepare an assessment of the validity of these web sites and be prepared to share your observations in class. Useful guidelines for the evaluation of the credibility of web postings may be found at the following URL: http://www.virtualchase.com/quality/checklist_print.html.
For: 1. http://www.atrazinefacts.com/growers-support-continued-atrazine-use/
-they need the popular herbicide atrazine to enhance other weed killing chemistry. Atrazine, on the market now for a half-century, has come under fire from researchers and activists who say it gets into surface water and affects fish and frogs
2.http://cornandsoybeandigest.com/crop-chemicals/farmers-speak-out-support-atrazine
-levels in raw and finished water are steadily declining. Atrazine was applied to 60% of conservation tillage and no-till corn acres.
Against: 1. http://www.savethefrogs.com/threats/pesticides/atrazine/index.html
-To allow the continued use and production of Atrazine, the EPA sets a dangerous precedent by condoning environmental destruction and implying that it is environmentally sound and ethical to dump poison on American soil and on Americans.
2. http://www.i-sis.org.uk/atrazine.php
-Atrazine is registered for use on range grasses for establishing permanent grass cover on rangelands.