Navigation Links
Salamanders suffer delayed effects of common herbicide

Pollution from a common herbicide might be causing die-offs in stream salamanders, according to biologists who say findings from their long-term study raise concerns over the role of atrazine in global amphibian declines.

The results also suggest that while impacts of the herbicide, atrazine, may not show up in short-term studies, even extremely low concentrations of the chemical may be deadly to amphibians in the long run.

"We are concerned that most studies used to make pesticide registration decisions and to derive safe concentrations last for about four days," said Jason R. Rohr, research associate at the Penn State Institutes of Energy and the Environment. "They often do not consider recovery processes, persistent effects of chemical exposure, or interactions among individuals within and between species that can affect our estimates of safe chemical concentrations."

Atrazine is one of the most widely used pesticides in the United States, and possibly the world. It is relatively long-lived and is even found at the poles. According to the U.S Environmental Protection Agency, it is one of the most common contaminants in ground and surface water.

Rohr and his colleagues Timothy M. Sesterhenn, doctoral candidate, Brent D. Palmer, associate professor, and Tyler Sager, doctoral candidate, all at the University of Kentucky, Lexington, exposed streamside salamander larvae to either 4, 40, or 400 parts per billion of atrazine until metamorphosis, the stage where the water-dwelling salamanders lose their gills and develop lungs that enable them to breathe in air. Scientists then tracked their survival to near reproductive age.

Results from the study, which lasted about 500 days, indicated that the two highest concentrations increased salamander mortality during exposure. However, this mortality benefited the survivors who experienced lower competition-related mortality after metamorphosis.

Nevertheless, this re covery from atrazine exposure paled in comparison to the persistent effects of atrazine that continued to cause mortality after exposure ceased, said researchers. Compared to salamanders not exposed to atrazine, survivors of the atrazine exposure had significantly lower survival 421 days after being exposed. In other words, effects of early exposure to the chemical were showing up over the long term, such that the net effect of atrazine exposure was even worse later in life than it was while the animals were being exposed.

"The biggest surprise was that it took nearly a year to detect the effects of atrazine at 4 parts per billion, which is just 1 part per billion above the maximum allowable level in drinking water set by the U.S Environmental Protection Agency," said Rohr, who presented his findings at a recent workshop organized by the U.S Geological Survey in St. Louis, Missouri.

"What this tells me is that we need to consider the long-term effects of chemicals, and that exposure to atrazine during formative stages might have permanent effects on these salamanders that increases their risk of mortality," he added.

While the mechanism by which atrazine causes elevated mortality remains unclear, Rohr says other scientists have evidence suggesting that this pesticide is an endocrine disruptor.

Such chemicals disrupt the production of hormones that are vital to normal bodily functions. Concentrations of atrazine as low as 0.1 parts per billion have been shown to cause male frogs to develop both male and female organs by altering their production of sex hormones.

Findings from Rohr's study, which was funded by the U.S Environmental Protection Agency, National Science Foundation, and the Kentucky Academy of Sciences, could have implications for global amphibian declines.

"Salamanders, and amphibians in general, are crucial to ecosystems, as both predators and prey. They can be seen as bioindicators of enviro nmental stress and harbingers of risk to other animals as well as humans," explained Rohr, also affiliated with Penn State's Center for Infectious Disease Dynamics.


'"/>

Source:Penn State


Related biology news :

1. Elephant seal pups suffer from ocean warming
2. New biologic treatment for tennis elbow may replace surgery for chronic sufferers
3. Wolves are suffering less from inbreeding than expected
4. Children of allergy sufferers prone to same problem
5. Swell gel could bring relief to back pain sufferers
6. How fish species suffer as a result of warmer waters
7. Report that delayed motherhood decreases life expectancy of mouse offspring
8. Low oxygen likely made Great Dying worse, greatly delayed recovery
9. Air travel and flu: Post-9/11 restrictions delayed start of season
10. Scientists ID molecular switch in liver that triggers harmful effects of saturated and trans fats
11. Alcohols effects on gene expression in the central nervous system
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/28/2016)... BANGALORE, India , April 28, 2016 /PRNewswire/ ... product subsidiary of Infosys (NYSE: INFY ), and ... global partnership that will provide end customers with ... banking and payment services.      (Logo: http://photos.prnewswire.com/prnh/20130122/589162 ... area for financial services, but it also plays a fundamental ...
(Date:4/28/2016)... Sweden , April 28, 2016 First ... M (139.9), up 966% compared with the first quarter of 2015 ... profit totaled SEK 589.1 M (loss: 18.8) and the operating margin ... 7.12 (loss: 0.32) Cash flow from operations was SEK ... The 2016 revenue guidance is unchanged, SEK 7,000-8,500 M. ...
(Date:4/26/2016)... and LONDON , April 26, ... of EdgeVerve Systems, a product subsidiary of Infosys ... announced a partnership to integrate the Onegini mobile ...      (Logo: http://photos.prnewswire.com/prnh/20151104/283829LOGO ) ... customers enhanced security to access and transact across ...
Breaking Biology News(10 mins):
(Date:4/29/2016)... , ... April 29, 2016 , ... ... necessary fundamentals to transform technology into a viable company, CereScan’s CEO, John Kelley, ... Mr. Kelley, a recognized leader and mentor in the Denver area business community, ...
(Date:4/29/2016)... ... April 29, 2016 , ... Summit for Stem Cell has received ... of a patient-specific stem cell therapy for the treatment of Parkinson’s disease. The Summit ... Loring at The Scripps Research Institute in San Diego, CA. , The ...
(Date:4/29/2016)... ... ... Implant Systems announced today that the two-level components for the Revolution™ Spinal System were ... components expand the capabilities of the system and allow Revolution™ to be utilized for ... company has seen significant sales growth in 1Q 2016, and the system is currently ...
(Date:4/29/2016)... Elekta is pleased to announce ... industry-leading treatment planning software, is available for clinical release. ... version 5.11 provides significant performance speed enhancements over ... to four times faster than in previous versions of ... standard Monte Carlo algorithm, users ...
Breaking Biology Technology: