This stuff doesn't seem to work on my dollar weed, even though I've been using it for years, it just keeps coming back........
Posted on 04/16/2008 1:22:17 PM PDT by Red Badger
Tadpoles develop deformed hearts and impaired kidneys and digestive systems when exposed to the widely used herbicide atrazine in their early stages of life, according to research by Tufts University biologists.
The results present a more comprehensive picture of how this common weed killer – once thought to be harmless to animals -- disrupts growth of vital organs in amphibians during multiple growth periods.
In recent years, worldwide amphibian population declines have fueled concerns over the potentially harmful effects of pesticides on "sentinel" organisms. Previous research had revealed negative effects of atrazine on amphibians extremely early and late in development. The Tufts study, published in the February 2008 edition of "Environmental Health Perspectives," examined tadpoles during an often overlooked period of development, organ morphogenesis.
Study Results Broadens Knowledge of Herbicide's Effects During a Vulnerable Stage
Organ morphogenesis is a brief, extremely sensitive phase in the tadpoles' growth cycle when they are starting to develop organs, noted Kelly A. McLaughlin, Associate Professor of Biology and lead researcher in the study. She explained that experiments were designed to broaden the understanding of how chemicals affect biological growth in amphibians over multiple stages of development. A $5,000 Tufts University Faculty Research Marshall Grant helped fund the study.
"Amphibians are very vulnerable to contamination since atrazine is used in the same environs where they live and breed," McLaughlin said.
Atrazine is used to control broadleaf and grassy weeds on golf courses and residential lawns, according to the Federal Environmental Protection Agency. Farmers use it to treat corn and soybeans. Atrazine blocks photosynthesis once it is absorbed by plants. Chronic exposure to the herbicide during metamorphosis altered amphibian gonadal development, according to previous research.
To study the consequences of atrazine exposure during organ morphogenesis, McLaughlin and her colleagues, Professor of Biology J. Michael Reed, doctoral candidate Jenny R. Lenkowski and Lisa Deininger, a Summer Scholars program undergraduate student, collected eggs from adult female frogs and then fertilized them in vitro. Scientists exposed the developing tadpoles to 10, 25 and 35 mg/L of atrazine. The 35 mg/L dosage simulated the average amount of herbicide used when it is applied in the field, said McLaughlin.
Multiple Impacts
Twelve to 24 hours after exposure to atrazine, tadpoles were examined for abnormal heart growth, visceral hemorrhaging, intestinal coiling, edema and apoptosis (normal cell death that is "programmed" by the body).
Compared with control populations, the tadpoles that were exposed to atrazine had a dramatically higher incidence of abnormalities. The degree of deformities generally corresponded to the size of the dose. After 48 hours of exposure, the point at which organ development is disrupted most profoundly, 57 percent of the tadpoles exposed to 35 mg/L of atrazine had hearts that were smaller than normal, compared with 2% to 3% for the two control groups.
Ectopic Cell Death
The Tufts scientists also examined atrazine exposed tadpoles for increased incidence of apoptosis by measuring levels of active caspase-3 in the pronephric kidney and midbrain. Caspase-3 is a protein needed for apoptosis to occur. They conducted measurements after 6, 12, 24 and 48 hours of exposure in tadpoles exposed to 25 and 35 mg/l of atrazine. Researchers observed that the atrazine-exposed tadpoles showed significant increases in caspase-3 levels in the kidney and midbrain at 12 hours and beyond when compared with controls. The findings indicated a high incidence of ectopic, or abnormal, apoptosis.
"The increased levels of apoptosis in the midbrain and pronephric kidney we observe suggest that atrazine may cause tissue malformation by inducing ectopic programmed cell death, either directly or indirectly through a mechanism that has not been identified," wrote the researchers.
McLaughlin and her team hope that their findings will lay a foundation for further research to determine the underlying mechanism by which atrazine exposure can affect so many different organ systems during the same stage of early development.
"Our work here documents that atrazine affects amphibian's early development, so the second question is how is this happening?" she said. "We know it blocks photosynthesis in plants but why does it have such negative impact on amphibians?"
This stuff doesn't seem to work on my dollar weed, even though I've been using it for years, it just keeps coming back........
This was Gods gift to corn farmers in the 60’s/70’s.
Seriously.
Well, now that the libs have succeeded in pricing up corn for ethanol, they'll have to find a reason to ban atrazine to make it harder to grow.
I’m out of farming for 20 years now, but I think that atrazine has been replaced by herbicides that are more ‘efficient’ in terms of effectiveness and carryover, which was always a problem.
Dead spots would appear in soybean fields the following year, irregularly from the carryover.
I WAS WONDERING WHY THERE ARE NO FROGS AROUND MY HOME LIKE THERE USED TO BE!.........
Don't worry, when they show up they'll all have eight legs!
What are we doing to ourselves? There is no way that this ONLY harms amphibians. Dandelions actually have very healthful properties, but we’d prefer our rolling lawns to be filled with harmful chemicals than wild natural weeds.
I agree.
Oh, brother.
What was the concentration level that the frogs were exposed to?
Go here to read the actual study report:
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2235211
35mg/litre bath for 48 hours.
See: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2235211
Each frog was tied to a 5 lb lead weight and submurged in atropin for exactly 30 min.
This was repeated 3 times a day for 52 weeks.
100 % of the test group showed death like syptoms at the 1st immursion test.
But in order to obtain more grant money the test were taken to their planned completion date.
This proves conclusivley that atrophine may hurt frogs and definitly raises Co2 levels.
Dear Jeff,
Never mind that was atrazine not atrophine. DUH
I bad.
Try baking soda and a spritz of water. Dollar-weed-b-gone!
>>35mg/litre bath for 48 hours.<<
I wonder what other substances would be harmful in those concentrations?
“Dandelions actually have very healthful properties”
BS. They’re weeds.
I use atrazine at recommended levels and have many thousands of frogs on the property. I’ve had so many that the lawn looks like it is moving some evenings. I also have thousands of toads, skinks, geckos, and various kinds of lizards and snakes.
They are good to eat when young...make a great salad.
After they get some age, they are good for nothin...
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