Atrazine kills amphibians

This video from the USA says about itself:

Leopard Frog Eggs and Courtship

I pointed my camera at this mass of Northern leopard frog eggs and walked away to look for snakes for a half hour. When I got back there was some cool footage!

From RSC Chemistry World in Britain:

Popular agrochemical linked to frog disease

Atrazine, one of the world’s most widely-used herbicides, makes frogs more susceptible to disease by compromising their immune system, US scientists suggest. The study provides further evidence linking the herbicide to a global decline in amphibian populations over the last three decades.

‘Amphibians are perhaps the most threatened vertebrates on the globe,’ says Jason Rohr, who led the work at the University of South Florida. Since the 1980s, he explains, amphibian populations have been declining at a startling rate.

Local chemical pollution has been blamed along with global climate change. But links between pollution and amphibian diseases are not clear, says Rohr.

Rohr and colleagues studied parasitic infection of the leopard frog (Rana pipiens) – a declining species – in wetlands across Minnesota. Of 240 possible factors, the researchers found that atrazine and phosphate, a common component of fertiliser, were the best predictors of the abundance of parasitic flatworm infection in the frogs – which can lead to malformed limbs, kidney damage, and death.

Back in the laboratory, the team found that frogs of various species exposed to atrazine were more likely to have a suppressed immune system, judging by measurements of immune cells. Atrazine also appeared to increase concentrations of the snails that harbour flatworm parasites.

Banning chances

Atrazine has already been suspected of causing a variety of ill-effects in frogs, such as growth defects and reduced sex hormone production. The chemical was banned on fears of groundwater contamination by the European Union in 2004. But it is still commonly used in the US; in 2006, the country’s Environmental Protection Agency concluded there was not enough evidence to suggest the chemical was harmful to humans.

‘I doubt that further documentation of atrazine’s harmful effects on frogs will prompt a ban in the US anytime soon,’ says Pieter Johnson, an expert on amphibians at the University of Colorado at Boulder, US.

‘In some respects amphibian development mirrors human development very closely and could therefore be used as a bioindicator. But in other regards, amphibians and humans are very different both ecologically and physiologically,’ Johnson adds. ‘Work such as this, in combination with more findings that atrazine could pose a threat to humans may push towards a ban in the US.’

A falling population of amphibians is itself a cause for concern, let alone any effect on humans, notes Rohr. Though bullfrogs and cane toads have been castigated for being invasive predators, most native amphibians are important for controlling insect pests that attack crops, and, as prey for birds and mammals, provide a link between freshwater and terrestrial ecosystems.

Lewis Brindley

See also here. And here.

Disease in Northern Leopard Frog Linked to Herbicide Atrazine: here.

American bullfrogs in the Netherlands: here.

7 thoughts on “Atrazine kills amphibians

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  2. Atrazine has received a lot of press lately and more consumers are finally becoming aware of the dangers of it in their drinking water.

    The state of Indiana released a statement just this week, encouraging consumers to use “point of use” drinking water filtration systems to protect themselves. Unfortunately, not all filters remove atrazine.

    I’m happy to say that the Multi-Pure drinking water systems DO remove atrazine, along with about 63 other harmful contaminants! Our filters cost less than bottled water and are certified by NSF to reduce the widest range of contaminants in the industry!

    If you’d like to know more, I’d be happy to talk to you about our products. We can wait for the government to do its part or we can solve the problem ourselves!


  3. Texas drought eases, helps endangered toad

    By JOHN McFARLAND Associated Press Writer © 2009 The Associated Press

    Oct. 13, 2009, 3:26PM

    DALLAS — Texas’ most endangered toad may not be croaking anytime soon.

    Only about 300 Houston toads remain in the wild, and scientists say the unforgiving drought has dried up ponds and marshland where they’ve released thousands of toads to try to repopulate their south-central Texas habitat. Now, after weeks of heavy rains, scientists are cautiously optimistic.

    “I am indeed more hopeful now,” said Texas State University professor Michael Forstner, who studies endangered species and leads the efforts to repopulate the toad’s habitat. “We have ponds that didn’t have any water that now have water. We have toads that were on the edge of not making it through the winter season that look like they’ll make it.”

    The toads once numbered an estimated 50,000 in south-central Texas, but are now found only in the sandy soils of forest land in six counties between Houston and Austin.

    Toads are light brown or gray and typically 2 inches to 3 1/2 inches long, but best known for the shrill whistles that males use for 10 to 15 seconds at a time to attract females. They were discovered in Houston in the 1950s but vanished from the area by the 1970s as their habitat dried up or was plowed over for real estate and natural forest fires were suppressed.

    For the past few years, researchers have been collecting and shipping toad eggs to the Houston Zoo, where they’re hatched and raised. About 5,000 toads have been released to the same ponds where they were taken from as eggs, but most have died in their drought-parched habitat.

    Texas’ drought — the most severe in the nation — has been baking the toads’ habitat, along with causing billions of dollars in agriculture damage, for two years. Nearly 7 percent of the state was classified in the two most extreme categories of drought last week, down from about 25 percent in July, according to the latest federal drought map.

    About 10 inches of rain has fallen since September is the region where most of the toads are found. Last year, about an inch of rain fell between September and October. About 4 inches fell during those months in 2007.

    Forstner believes toads that survived the drought and scorching summertime heat burrowed into the sand or near tree roots where they can scrounge enough water and food.

    Paul Crump, the amphibian conservation manager at the Houston Zoo who has raised and released the toads, said the rains are crucial.

    “Outside of mating, they don’t go looking for water, so they require environmental moisture to survive,” he said.

    The real test now is whether the toads will reproduce. They breed in ponds from January to April, and in the right conditions a single Houston toad can release 3,000 eggs in a season. Most of the 4,000 toads released this year won’t be old enough to mate, so researchers are hoping for big results in 2011.

    But the toad has far more threats than just the drought.

    Real estate and agricultural development have depleted the species’ habitat, and naturally occurring forest fires that keep foliage diverse and attract bugs for food have been suppressed, Forstner said.

    Fire ants kill baby toads and cattle ruin the habitat of the bugs that the toads eat. Researchers also are studying how pesticides and other runoff affect the toad.

    The toads were originally found in nine counties in south-central Texas, but they have vanished from Harris, Liberty and Fort Bend in recent years. They are found mostly in Bastrop, but also in Leon, Robertson and Milam counties. They’ve historically also been in Lee and Lavaca counties, but recent surveys did not detect any. Forstner is hoping a few are still there, just laying low.

    “The animal is simply going away, one county at a time,” Forstner said.

    In Bastrop County, one research site had 150 male toads as recently as 2005. This year, there are 18.

    There used to be so many toads in some Bastrop County ponds that you couldn’t catch them all, but “now we wait all night for two,” Forstner said.

    Researchers are so concerned about extinction that they’ve been making extensive recordings of the toads “chorusing,” so the sound won’t be lost if the species dies off, as it was with the now extinct passenger pigeon.

    Crump said program will continue as long as it takes to get the animal off the endangered list, no matter how many toads need to be released.

    “It could be a million,” he said.


  4. EPA concluded that the risks could be mitigated by adding restrictions to the labels and monitoring drinking water exposures. It concluded that atrazine was unlikely to be a human carcinogen,


  5. Re #4: the comment claims to be by “Tyrone Hayes”, while in fact it is from . Impersonating someone else, especially someone with different views from your own, is NOT the way to comment at this blog, or at any other blog for that matter. There is a name for that kind of behaviour: trolling.

    As for the EPA, it is a branch of the US federal government. Given the many links of the US government to big business (including atrazine merchant) interests, I would not trust them uncritically.


  6. Some of the male frogs that were exposed to atrazine didn’t change sex like the cloned dinosaurs in the Hollywood blockbuster, but they were chemically castrated. These fellas were unable to attract the ladies, and when paired off with females, were extremely infertile and had low sperm counts. Many were also missing basic male features, like breeding glands.


  7. Pingback: Herbicides threaten kangaroos, new research | Dear Kitty. Some blog

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