NEWS WISE (Charlottesville, Virginia) 11 January 06 Press Release: Atrazine, Nitrate, Acidity Contribute to World-Wide Amphibian Declines
Three new studies provide insight into the well-documented global decline in amphibian populations. Researchers found that the use of agrochemicals, which pollute the habitats and disturb the natural breeding cycles of amphibians, was one major cause of the population decline.
[Effects of nitrate and atrazine on larval development and sexual differentiation in the Northern leopard frog Rana pipiens, Effects of atrazine and iridovirus infection on survival and life-history traits of the long-toed salamander (Ambystoma macrodactylum), Acid exposure is an immune disruptor in adult Rana pipiens; Environmental Toxicology and Chemistry) 2006; Vol. 25(1):65-71, 168-173, 199-202
Atrazine, Nitrate, Acidity Contribute to World-Wide Amphibian Declines
Three new studies provide insight into the well-documented global decline in amphibian populations. Researchers found that the use of agrochemicals, which pollute the habitats and disturb the natural breeding cycles of amphibians, was one major cause of the population decline. These studies are published in the latest issue of Environmental Toxicology and Chemistry.
1. Effects of nitrate and atrazine on larval development and sexual differentiation in the Northern leopard frog Rana pipiens; Vol. 25(1):65-71
In the first study, researchers concluded that the combined effect of atrazine and nitrate at environmentally relevant concentrations influences frog populations and affects maturation rates. Previous studies that tested atrazine, the most commonly used herbicide in the United States, reported that this chemical disturbs gonad differentiation during larval development. Both atrazine and nitrate have been found to be endocrine-disrupting chemicals. The highest concentrations of these chemicals occur during high rainfall events, which coincide with the amphibian breeding season in temperate climates.
2. Effects of atrazine and iridovirus infection on survival and life-history traits of the long-toed salamander (Ambystoma macrodactylum); Vol. 25(1): 168-173
Atrazine is further studied in another paper that looks at its interaction with the infectious disease iridovirus in the long-toed salamander. Study results showed that relatively low concentrations of atrazine could ameliorate the effects of an emerging infectious disease. To a higher degree, stronger concentrations of atrazine affected metamorphosis in the larval stage.
“Multifactorial studies are essential both in understanding and disentangling the complexities of amphibian declines and in understanding the potential implications for human populations,” the researchers said.
3. Acid exposure is an immune disruptor in adult Rana pipiens; Vol. 25(1): 199-202
The last study examined the effect of acidic water on the immune system of frogs, finding that acid exposure acts as a disruptor. Since the Industrial Revolution and even after the Clean Air Act was enacted, acid rain has continued to disrupt the natural levels of acidity in animal habitats. The researchers said that acidity may play a role in population declines of acid-sensitive amphibians, such as the frog in the northeastern United States.
To read study No. 1, visit: http://www.allenpress.com/pdf/entc(1)_a25_01 65-71.pdf
Study No. 2: http://www.allenpress.com/pdf/entc(2)_a25_01 168-173.pdf
Study No. 3: http://www.allenpress.com/pdf/entc(3)_a25_01 199-202.pdf
Atrazine, Nitrate, Acidity Contribute to World-Wide Amphibian Declines