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  • Learn About Colony Collapse Disorder and How to Protect Bees
  • Learn To Manage Weeds Without Chemical Pesticides

Frogs and other Amphibians

also see glyphosate and atrazine

The abiliy of several registered pesticides to decrease immunity and make animals (and plants) susceptible to disease has been known for some time, at least since they found over 20 years ago that amphibians exposed to DDT in Ontario (including in Point Pelee National Park) were much more susceptible to disease. This is reiterated in Ecotoxicology of Amphibians and Reptiles, Second Edition, (2010) edited by Donald W. Sparling, Greg Linder, Christine A. Bishop, Sherry Krest, p 281. I guess it took bees to bring it to the general public and most researchers' attention. 

Aminomethylphosphonic acid alters amphibian embryonic development at environmental concentrations  (Environmental Research, Volume 190, November 2020, MarionCheron,FrançoisBrischoux)   Environmentally relevant concentrations of AMPA (the main metabolite of glyphosate) have been found to affect embryonic survival, development duration and hatchling morphology in spined toads. Non-linear concentration response patterns were likely to occur at low concentrations, meaning that the effect did not increase with the dose – greater effects were found at low concentrations of AMPA than higher levels. The study concluded that regulatory decision-making needs to go beyond the use of high-dose studies to identify official no-effect concentrations.'     'Our experimental concentrations of AMPA were 100–6000 times lower than official Predicted-No-Effect-Concentrations. We found that these low-level concentrations of AMPA decreased embryonic survival, increased development duration and influenced hatchling morphology.'

filed under Wildlife/amphibians 

Pesticides in the real world: The consequences of GMO-based intensive agriculture on native amphibians  (M. Gabriela Agostinia et al, Biological Conservation, Vol. 241, Jan. 2020, 108355)   ' ...we evaluated the effects (survival and mobility) of common pesticides applied by farmers (cypermethrinchlorpyrifosendosulfanglyphosate, and 2,4-Dichlorophenoxyacetic acid) on tadpoles. We assessed these effects in four common amphibian species from South America across 91 ponds located in the Pampas of central Argentina.'

  • Tadpole survival dramatically decreased after pesticides reached the ponds.
  • 93% of surviving tadpoles exposed to insecticides, exhibited impairment of mobility.
  • Glyphosate exposures caused sublethal effects, reducing tadpole mobility in 79%.
  • We detected pesticide impacts on amphibians in real exposure scenarios.

Neonicotinoids Found to Change Frog Behavior  Beyond Pesticides, November 15, 2018)  In a study published late last month, scientists from the National Wildlife Research Center in Ottawa, Canada found that chronic exposure to real-world levels of the neonicotinoid imidacloprid limits the ability of juvenile wood frogs to escape a predator attack.

Literature review of impacts of glyphosate herbicide on amphibians: What risks can the silvicultural use of this herbicide pose for amphibians in B.C.?  by  Purnima P. Govindarajulu, Ph.D. includes an EXECUTIVE SUMMARY. "the expected environmental concentration (EEC) of glyphosate herbicides of 1.43 mg a.e./L is at or above the estimated LC50 (lethal dose kiling 50% of the study animals) value for some amphibians." Many serious sublethal effects are known to occur well below this concentration. Indirect impacts also occur...The formulant POEA appears more toxic to amphibians. Alternative formulations that do not use POEA are now available in some parts of the world (but not in Canada) and these formulations have been shown to have much lower toxicity to amphibians. There is insufficient information on the levels of glyphosate contamination in small ephemeral wetlands, which are favoured habitats of amphibians, and which may be exposed to direct overspraying with herbicide under current use guidelines."  also filed under fact sheets/ glyphosate 

Glyphosate Stresses Tadpoles to Produce More Venom  (Beyond Pesticides, August 9, 2017)  Scientists tested the effects of formulated glyphosate products on toad tadpoles through experiments in a laboratory setting, as well as a mesocosm, a controlled outdoor environment that replicates natural conditions. This is not the first instance of glyphosate altering the normal development of amphibians. Earlier this year, the same team of researchers found that glyphosate products reduced the survival and growth of common toads, and otherwise slowed down their development. A 2012 study from the University of Pittsburg found that glyphosate induced morphological changes in the development of leopard and wood frogs similar to those seen under significant predatory threat. The results of accumulated scientific research on stress-induced changes following glyphosate exposure points to underlying flaws in U.S. regulation of pesticides. Ecosystem-wide impacts caused by the secondary effects of pesticide use are rarely, if ever, considered under the risk assessment framework used to register pesticides.

Report Links Pesticide Exposure to Globally Declining Amphibian Population 3/8/2013 12:02:41 PM By Victoria Pitcher. Link to full scientific report. Effects were not restricted to a specific class of pesticides and seem to be influenced not only by the active substance but also the formulation additives  The commercially available Headline formulation caused 100% mortality just after 1 h at the label rate.

Pesticides Contaminate Frogs in California National Parks (Beyond Pesticides, July 30, 2013) 98 types of pesticides were tested for, traces of which were found in frog tissues from all sites. Two fungicides, pyraclostrobin and tebuconazole, and one herbicide, simazine, were the most frequently detected compound. This was the first time these compounds have ever been reported in wild frog tissues. As of August 2013, in Canada, there are 23 pyraclostrobin,  21 tebuconazole and 6 simazine products registered. While simazine is less likely to be used on a large scale in Saskatchewan, it has one domestic formulation (LATER'S CALCIDE LIQUID VEGETATION KILLER) for weeds on hard surfaces and along fences. 

Common pesticides 'can kill frogs within an hour'.(24 January 2013. The Guardian - environment} New research suggests the chemicals are playing a significant and previously unknown role in the global decline of amphibians. Most striking results fungicides pyraclostrobin (BASF) and Captan killing all the test animals within an hour when applied at the recommended rate, and several products including the insecticide dimethoate (Cygon),used at 10% concentration killing 40% of animals within a week.The Headline formulation containing more of the formulant naphta was much more lethal. As of February 2012, 20 pyraclostrobin including 4 called Headline and dimethoate products are registered in Canada. No formulant is currently listed on any Headline label. (original article published  in Scientific Reports)