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:

(Date:11/20/2015)... 20, 2015 NXTD ) ("NXT-ID" ... the growing mobile commerce market and creator of the ... , was recently interviewed on The RedChip Money ... this weekend on Bloomberg Europe , Bloomberg Asia, ... --> NXTD ) ("NXT-ID" or the "Company"), a ...
(Date:11/18/2015)... Nov. 18, 2015  As new scientific discoveries deepen ... and other healthcare providers face challenges in better using ... patients. In addition, as more children continue to survive ... adulthood and old age. John M. Maris, ... Hospital of Philadelphia (CHOP) . --> ...
(Date:11/17/2015)... November 17, 2015 Paris ... 2015.  --> Paris , qui ... DERMALOG, le leader de l,innovation biométrique, a inventé ... passeports et empreintes sur la même surface de balayage. ... et l,autre pour les empreintes digitales. Désormais, un seul ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... San Francisco, CA (PRWEB) , ... November 25, ... ... leading microbial genomics company uBiome, were featured on AngelList early in their initial ... by launching an AngelList syndicate for individuals looking to make early stage investments ...
(Date:11/24/2015)... 24, 2015 /CNW/ - iCo Therapeutics ("iCo" or "the ... results for the quarter ended September 30, 2015. ... dollars and presented under International Financial Reporting Standards ... ," said Andrew Rae , President & ... are not only value enriching for this clinical ...
(Date:11/24/2015)... 24, 2015 --> ... report "Oligonucleotide Synthesis Market by Product & Services (Primer, ... Diagnostic, DNA, RNAi), End-User (Research, Pharmaceutical & Biotech, Diagnostic ... the market is expected to reach USD 1,918.6 Million ... a CAGR of 10.1% during the forecast period. ...
(Date:11/24/2015)... Technologies Ltd. (OTCQB: TIKRF) today announced that its Annual General Meeting of ... Israel time, at the law offices of Goldfarb ... Floor, Tel Aviv, Israel . ... Tamir to the Board of Directors; , election of ... of an amendment to certain terms of options granted to our Chief ...
Breaking Biology Technology: