New regulatory approaches may be needed to assess environmental risks of agricultural growth promoters, and similar human pharmaceuticals, following research that shows a newly found reversion mechanism allows unexpected persistence of the steroidal substances in aquatic environments.
Ed Kolodziej is an associate professor and researcher in the University of Nevada, Reno's College of Science and project leader of a collaborative multi-disciplinary research team that includes the University of Iowa and Truman State. He and his team found a new mechanism where chemicals transform, under certain conditions, to avoid detection, which may account for unexplained observations of endocrine disruption in aquatic organisms.
Credit: Photo courtesy of University of Nevada, Reno.
Results of the research will be published in an article in the renowned journal Science – the weekly journal of AAAS, the science society – next month and are available immediately online in Science Express.
"We investigated trenbolone, an anabolic steroid, and found that the photochemical breakdown isn't the end of its life cycle," Ed Kolodziej, co-author of the paper and environmental engineering professor at the University of Nevada, Reno, said. "Our team found that these substances, after a rapid breakdown in sunlight, are capable of a unique transformation in aquatic environments under various temperature and light-cycle scenarios where the process is reversed."
Kolodziej, project leader of a collaborative multi-disciplinary research team that includes the University of Iowa and Truman State, said this newly found mechanism may account for unexplained observations of endocrine disruption in aquatic organisms.
"Right now, I'm not alarmed, just concerned and interested in defining the real ecological risks associated with the widespread use of potent steroidal pharmaceuticals," Kolodziej, who has been studying the effects of these substances on aquatic ecosystems for 12 years, said. "This implies uncertainty with the current environmental risk assessments or ecotoxicology studies used by regulatory agencies, researchers and pharmaceutical companies."
The team used laboratory and field studies to explore the process. They found that the steroid's chemical compounds, while breaking down as expected in sunlight, never fully disappeared; even in conditions that mimicked surface water, a small percentage of the chemical structure remained after extended sunlight. The remains regenerated themselves at night, in some cases to up to 70 percent of the metabolites initial mass."
"We knew something unique was going on," David Cwiertny, Kolodziej's research partner from the University of Iowa, said. "In daylight, it essentially hides in another form, to evade analysis and detection, and then at nighttime it readily transforms back to a state that we can detect."
The researchers validated the lab results with two experiments in the field – one with water taken from the Iowa River in Iowa City, Iowa and the other from samples taken from a collection pond at a cattle rangeland and research operation in California's Central Valley run by the University of California, Davis.
Trenbolone is a federally approved drug widely used by the beef industry to promote weight gain and to increase feeding efficiency in cattle. The drug, although popular in the bodybuilding and weightlifting communities, and as an athletic performance enhancer, has long been banned for human use, and also is banned for agricultural uses in the E.U.
Trenbolone has been considered safe for ecosystems due to its initially rapid degradation, with studies pointing to an environmental half-life of less than a day. Studies have indicated that low concentrations of these endocrine disrupting environmental steroids affect fish, by reducing egg production of females and skewing the sex of some species.
The article can be found at the Science Express website: http://www.sciencemag.org/content/early/recent.
Kolodziej is an associate professor in the University of Nevada, Reno's College of Engineering. His website can found at http://www.unr.edu/cee/homepages/kolodziej/index.html.
Founded in 1874 as Nevada's land-grant university, the University of Nevada, Reno ranks in the top tier of best national universities. With nearly 19,000 students, the University is driven to contribute a culture of student success, world-improving research and outreach that enhances communities and business. Part of the Nevada System of Higher Education, the University has the system's largest research program and is home to the state's medical school. With outreach and education programs in all Nevada counties and home to one of the largest study-abroad consortiums, the University extends across the state and around the world. For more information, visit http://www.unr.edu.
Mike Wolterbeek | EurekAlert!
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Materials Sciences
18.07.2018 | Life Sciences
18.07.2018 | Health and Medicine