Scientists have long looked at the presence of endocrine disruptors and their role in the environment. A new study from the University of Nevada, Reno, raises questions about how anabolic steroids may regenerate in aquatic systems. The study - to be published in the journal Science - looked at trenbolone and found that the photochemical breakdown of the compound may not be the end of its life cycle.
"Right now, I'm not alarmed," says Ed Kolodziej, co-author of the paper and environmental engineering professor at the university. He adds that he is "just concerned and interested in defining the real ecological risks associated with the widespread use of potent steroidal pharmaceuticals."
Kolodziej found that the substances, after a rapid breakdown in sunlight, are capable of a unique transformation in aquatic environments under various temperatures and light-cycle scenarios where the process is reversed. He notes that this newly found mechanism may account for unexplained observations of endocrine disruption in aquatic organisms.
The project was a collaboration between University of Nevada, Reno, University of Iowa and Truman State.
This work does imply uncertainty with the current environmental risk assessments or ecotoxicology studies used by regulatory agencies, Kolodziej says.
The team used lab and field studies to explore the process. They found that the steroid's chemical compounds, which broke 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 and the remains would regenerate at night, in some cases up to 70% of the metabolites of the initial mass returned.
Trenbelone is widely used in the beef industry to promote weight gain and to increase cattle feed efficiency. It has been considered safe for ecosystems due to its initially rapid degeneration, with studies pointing to an environmental half-life of less than a day. Studies have shown in the past that low concentrations of endocrine disrupting environmental steroids affect fish and other aquatic species.
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