Atrazine is the second-most widely used herbicide in the U.S. More than 75 million pounds of it are applied to corn and other crops, and it is the most commonly detected pesticide contaminant of groundwater, surface water and rain in the U.S.
The new review, compiled by 22 scientists studying atrazine in North and South America, Europe and Japan, appears in the Journal of Steroid Biochemistry and Molecular Biology.
The researchers looked at studies linking atrazine exposure to abnormal androgen (male hormone) levels in fish, amphibians, reptiles and mammals and studies that found a common association between exposure to the herbicide and the “feminization” of male gonads in many animals.
The most robust findings are in amphibians, said University of Illinois comparative biosciences professor Val Beasley, a co-author of the review. At least 10 studies found that exposure to atrazine feminizes male frogs, sometimes to the point of sex reversal, he said.Beasley’s lab was one of the first to find that male frogs exposed to atrazine in the wild were more likely to have both male and female gonadal tissue than frogs living in an atrazine-free environment. And in a 2010 study, Tyrone Hayes, a professor of integrative biology at the University of California at Berkeley and lead author of the review, reported in the Proceedings of the National Academy of Sciences that atrazine exposure in frogs was associated with “genetic males becoming females and functioning as females,” Beasley said.
“And this is not at extremely high concentrations,” he said. “These are at concentrations that are found in the environment.”
The new review describes the disruptions of hormone function and sexual development reported in studies of mammals, frogs, fish, reptiles and human cells exposed to the herbicide. The studies found that atrazine exposure can change the expression of genes involved in hormone signaling, interfere with metamorphosis, inhibit key enzymes that control estrogen and androgen production, skew the sex ratio of wild and laboratory animals (toward female) and otherwise disrupt the normal reproductive development and functioning of males and females.
“One of the things that became clear in writing this paper is that atrazine works through a number of different mechanisms,” Hayes said. “It’s been shown that it increases production of (the stress hormone) cortisol. It’s been shown that it inhibits key enzymes in steroid hormone production while increasing others. It’s been shown that it somehow prevents androgen from binding to its receptor.”The review also consolidates the evidence that atrazine undermines immune function in a variety of animals, in part by increasing cortisol.
There also are studies that show no effects – or different effects – in animals exposed to atrazine, Beasley said. “But the studies are not all the same. There are different species, different times of exposure, different stages of development and different strains within a species.” All in all, he said, the evidence that atrazine harms animals, particularly amphibians and other creatures that encounter it in the water, is compelling.
“I hope this will stimulate policymakers to look at the totality of the data and ask very broad questions,” Hayes said. “Do we want this stuff in our environment? Do we want – knowing what we know – our children to drink this stuff? I would think the answer would be no.”Editor’s notes: To reach Val Beasley, call 217-897-6209; email email@example.com.
U. of I. News Bureau
Diana Yates | University of Illinois
Rising water temperatures could endanger the mating of many fish species
03.07.2020 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
Moss protein corrects genetic defects of other plants
03.07.2020 | Rheinische Friedrich-Wilhelms-Universität Bonn
Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.
Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....
Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.
Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...
A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...
Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"
The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...
With an X-ray experiment at the European Synchrotron ESRF in Grenoble (France), Empa researchers were able to demonstrate how well their real-time acoustic monitoring of laser weld seams works. With almost 90 percent reliability, they detected the formation of unwanted pores that impair the quality of weld seams. Thanks to a special evaluation method based on artificial intelligence (AI), the detection process is completed in just 70 milliseconds.
Laser welding is a process suitable for joining metals and thermoplastics. It has become particularly well established in highly automated production, for...
02.07.2020 | Event News
19.05.2020 | Event News
07.04.2020 | Event News
03.07.2020 | Life Sciences
03.07.2020 | Studies and Analyses
03.07.2020 | Power and Electrical Engineering